**Formation and High-Temperature Stability of Co-SputteredTi-AlandMultilayeredTi/Al**

**Substrates**

 **Si**

#### **Marietta Seifert \*, Eric Lattner, Siegfried B. Menzel, Steffen Oswald and Thomas Gemming**

**Oxidized**

Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany<EMAIL_ADDRESS>(E.L<EMAIL_ADDRESS>(S.B.M<EMAIL_ADDRESS>(S.O<EMAIL_ADDRESS>(T.G.)

**\*** Correspondence<EMAIL_ADDRESS>Tel.: +49-351-4659-639

Received: 24 March 2020; Accepted: 23 April 2020; Published: 27 April 2020

**Abstract:** Ti-Al thin films with a thickness of 200 nm were prepared either by co-sputtering from elemental Ti and Al targets or as Ti/Al multilayers with 10 and 20 nm individual layer thickness on thermally oxidized Si substrates. Some of the films were covered with a 20-nm-thick SiO2 layer, which was used as an oxidation protection against the ambient atmosphere. The films were annealed at up to 800 ◦C in high vacuum for 10 h, and the phase formation as well as the film architecture was analyzed by X-ray diffraction, cross section, and transmission electron microscopy, as well as Auger electron and X-ray photoelectron spectroscopy. The results reveal that the co-sputtered films remained amorphous after annealing at 600 ◦C independent on the presence of the SiO2 cover layer. In contrast to this, the *γ*-TiAl phase was formed in the multilayer films at this temperature. After annealing at 800 ◦C, all films were degraded completely despite the presence of the cover layer. In addition, a strong chemical reaction between the Ti and SiO2 of the cover layer and the substrate took place, resulting in the formation of Ti silicide. In the multilayer samples, this reaction already started at 600 ◦C.

**Keywords:** TiAl; thin films; surface acoustic waves; high-temperature stability; phase formation

## **1. Introduction**

Ti-Al-based materials are widely used in industry, especially for aerospace applications in aircraft engines [1] or gas turbines [2] due to their high thermal stability in combination with a low density. Therefore, much research has been performed on Ti-Al based bulk material and on Ti-Al coatings. There is also literature on Ti-Al thin films; however, in general, this refers to films with a thickness of a few or tens of μm [3–5]. Besides the application as bulk material or μm-thick coating, Ti-Al films with a thickness of a few 100 nm are interesting as a metallization in surface acoustic wave (SAW) devices operating at elevated temperatures (above 400 ◦C).

Current research on high temperature stable metallizations for SAW devices mainly focuses on Pt based materials due to their noble character [6,7], or among others, Ir or Ir-based alloys [8,9]. Since Pt has a strong tendency to agglomerate, oxide dispersion hardening (ODS) was applied to stabilize the films [10]. Another alternative are ODS stabilized Mo films [11], because of the very high melting temperature of Mo, and therefore expected low creep at the operation temperature of the devices (600–800 ◦C). In our group, during the last years, many efforts were made to improve the high temperature stability of RuAl thin films. RuAl is a promising material due to its high melting temperature of 2050 ◦C [12] and its strong oxidation and corrosion resistance [13]. Recently, we realized RuAl thin films that were stable up to 800 ◦C in air and 900 ◦C in HV for at least 10 h [14].

The mass of the metal used for electrodes determines the velocity of the propagating SAW, and, thus, the coupling coefficient. Furthermore, heavy metals are especially used for reflective

electrodes as, for instance, in resonator structures in the filter segment of SAW technology. In contrast, in other applications of SAW technology, e.g., in sensors, SAW-driven microfluidic actuators or SAW-based tags, where delay lines or reflective delay lines are often used, a more lightweight metal is often preferred to reduce the reflection of the acoustic energy at each of the finger electrodes.

Therefore, a wide range of mass loading provided by the metals used for the finger electrodes is essential to enhance the range of application in SAW technology. The above-listed materials, on which current research for high temperature metallizations focuses, all possess a high density (e.g., Pt: 21.45 g/cm3; Mo: 10.28 g/cm3; and RuAl: ≈ 8 g/cm3). In contrast to this, Ti-Al has a much lower density (3.9–4.3 g/cm3 [15]), which allows different design variations and with this additional applications of the devices.

For the very thin Ti-Al films (few 100 nm), the realization of the high temperature stability is more challenging than for the thick coatings or bulk materials. In the latter, during heat treatment at elevated temperatures, Al is oxidized and a several μm-thick protective oxide scale is formed on top of the sample. As a consequence, a thin Ti-Al film is destroyed completely under these conditions. Therefore, an additional barrier layer on top of the Ti-Al film is required to prevent oxidation. In this work, we applied SiO2 as a cover layer material, since it successfully protected RuAl thin films from oxidation up to 800 ◦C in air for at least 10 h [14,16]. A cover layer of Al2O3 was tested in the former work for RuAl thin films as well; however, it led to a stronger oxidation of the RuAl film as compared to SiO2 [16].

This paper presents a study on very thin (200 nm) Ti-Al films with focus on the high-temperature stability as well as on the γ-TiAl phase formation. Co-sputtered Ti-Al films with and without SiO2 protection layer were compared with multilayered Ti/Al films with SiO2 cover.

### **2. Materials and Methods**

Ti-Al thin films with a thickness of 200 nm were prepared on Si substrates with 1 μm of thermally grown SiO2 on top by two different routines using DC sputtering. On the one hand, co-sputtering from elemental Ti and Al targets (100 mm target, 3.5 × 10−3 mbar, 500 W for Ti and 280 W for Al) was applied to deposit Ti-Al alloy films with a composition of 50:50. On the other hand, multilayer systems were prepared by subsequent sputtering of Ti and Al layers (3.2 × 10−3 mbar, 500 W). The multilayer (ML) stacks were started with a Ti layer so that the uppermost layer consisted of Al. Two ML systems with a thickness of the individual layers of 10 or 20 nm were deposited. Since the total thickness of the film was kept constant at 200 nm, the Ti10nmAl10nm bilayer was repeated 10 times and the Ti20nmAl20nm 5 times. A 20-nm-thick SiO2 cover layer (RF sputtering, 200 mm target, 3.5 × 10−3 mbar, 2000 W) was added on top of some of the samples as an oxidation barrier. The SiO2 films were deposited by sputtering from a SiO2 target at a deposition temperature of 180 ◦C with a sputtering gas of Ar and O2 (ratio of 6:1). The depositions of the metallization and the cover layers were carried out in different chambers of the same cluster tool (CREAMET 350-CL 6, CREAVAC-Creative Vakuumbeschichtung GmbH, Dresden, Germany) without interruption of the high vacuum.

The films were annealed in high vacuum (HV, pressure lower than 10−5 mbar) for 10 h at 400, 600, and 800 ◦C. X-ray diffraction in Bragg Brentano geometry (XRD, Philips X'pert, Co K α) was applied to analyze the phase formation. To reveal the full texture information and to confirm the formation of the γ-TiAl phase, pole figure measurements of the (101) and (110) lattice planes were performed (Philips X'Pert MRD, Cu K α). For the γ-TiAl phase, the diffraction angle 2θ is 38.7◦ for the (101) and 45.3◦ for the (110) pole. To realize an optimum quality of these analyses, prior to each measurement, overview scans were performed with this theoretical value to identify the respective pole. Then, for each sample, the 2θ value was measured at this position, since it might slightly deviate from the theoretical value due to a small change of the composition or due to stresses in the thin film during growth and subsequent annealing. This optimized 2θ value was used for the texture measurement. The theoretical peak position was used if it was not possible to identify a pole with the overview scan.

Cross sections of the samples were prepared by the focussed ion beam technique (FIB) and imaged by scanning electron microscopy (SEM) in the same device (Zeiss 1540 XB Cross Beam, Carl Zeiss Microscopy GmbH, Oberkochen, Germany).

The distribution of the elements across the film thickness was analyzed by Auger electron spectroscopy (AES, JEOL JAMP-9500 Field Emission Auger Microprobe). Ar sputtering (energy of Ar ions: 1 keV, current of 0.7 × 10−6 A) was done for a time span between 30 and 120 s, and, subsequently, the AES spectra were recorded. These processes were repeated until the substrate was reached. The evaluation of the spectra was carried out using standard single element sensitivity factors of the PHI-Multipak software [17]. The analysis of the AES peak shape and position additionally allows deriving conclusions on the oxidation state of the metal elements.

For selected samples, X-ray photoelectron spectroscopy (XPS, PHI 5600 CI-System, Physical Electronics) was performed. Non-monochromatic MgK α X-rays (400 W) were used to excite the sample and a hemispherical electron analyzer working at a pass energy of 29 eV was applied to record the spectra. XPS allows a more detailed analysis of the oxidation state of the elements. In this case, depth profiles were also obtained by alternately sputtering with Ar ions (3.5 keV) and measuring the spectra.

Annular dark field scanning transmission electron microscopy (ADF-STEM, Technai F30, FEI company, Hillsboro, OR, USA) was used to image the local morphology. The local composition was determined by energy dispersive X-ray spectroscopy in the TEM (Octane T Optima, EDAX Company, Mahwah, NJ, USA). The TEM lamella were prepared using the FIB technique.

## **3. Results and Discussion**

## *3.1. Phase Formation*

Figure 1 presents the results of the XRD measurements of the different samples in the as-prepared state and after annealing at 400, 600, and 800 ◦C in HV. It can be seen that for both co-sputtered films no peaks were visible for all sample states (Figure 1a,b). In contrast to this, clear XRD peaks were present for the ML films. In the as-prepared state, a superposition of the Ti (002, theoretical peak position: 2θ = 44.96◦) and Al (111, theoretical peak position: 2θ = 45◦) appeared (Figure 1c,d). The measured peaks were slightly shifted with respect to the theoretical position, which might be due to stresses in the thin films. Annealing at 400 ◦C led to a decrease of the peak intensities. However, there was still a superposition of two XRD peaks.

**Figure 1.** XRD measurements on: (**a**) a co-sputtered Ti-Al film; (**b**) a co-sputtered Ti-Al film with SiO2 cover layer; (**c**) a Ti/Al ML film with 10 nm individual layer thickness; and (**d**) a Ti/Al ML film with 20 nm individual layer thickness, both with SiO2 cover layer.

The phase formation in μm thick Ti/Al ML films was analyzed by various authors. For very thin individual layers (2 nm), a transition from (Ti) + (Al) → disordered TiAl + (Ti) → γ-TiAl + α2-Ti2Al was described by Ramos et al. [18]. In contrast to this, for thicker individual layers (100 nm), the authors described the transition from Al and Ti to γ-TiAl via a TiAl3 intermediate phase. The occurrence of TiAl3 in the phase sequence during annealing of Ti/Al ML samples was also described by Illekova et al. for an individual layer thickness of 20 nm or more [5]. For Al rich Ti-Al ML samples (substrate/40 nm Ti/180 nm Al/40 nm Ti/180 nm Al), the formation of TiAl3 was also

observed after a heat treatment at 450 ◦C [19,20]. The two peaks measured in our work after annealing at 400 ◦C are therefore ascribed to Ti (002, now measured at a slightly higher 2θ of 45.1◦) and TiAl3 (103 or 112, theoretical 2θ = 45.82◦, measured at 46.0◦).

After annealing at 600 ◦C, one single peak was measured for both ML samples, which can be attributed to the γ-TiAl (101) peak (theoretical position: 2θ = 45.27◦, measured at 45.6◦). After annealing at 800 ◦C, the TiAl peak disappeared.

Pole figure measurements were performed to confirm the formation of the γ-TiAl phase in the ML films. In addition, these measurements allowed to exclude that in the co-sputtered films the γ-TiAl phase has formed with a tilted texture, which cannot be detected by XRD in Bragg Brentano geometry. Figure 2 summarizes the pole figures of the (110) and (101) γ-TiAl poles of the four different samples annealed at 600 ◦C for 10 h. Since the pole figures are scaled to their respective maximum, in addition, the azimuthally averaged intensity versus the tilt angle Ψ is presented to allow a comparison between the different samples. It can be seen that both co-sputtered samples with or without SiO2 cover layer did not show any phase formation (see Figure 2a,b). The pole, which was visible in the TiAl (110) pole figure at Ψ = 54◦ was caused by the Si (220) lattice planes. Their 2θ value of 47.3◦ (Cu K α) is close to that of the TiAl (110), so that it is also measured. Besides this, no significant intensity was detected.

**Figure 2.** Results of the texture measurements of: (**a**) a co-sputtered Ti-Al film; (**b**) a co-sputtered Ti-Al film with SiO2 cover layer; (**c**) a ML Ti/Al film with 10 nm individual layer thickness; and (**d**) a ML Ti/Al film with 20 nm individual layer thickness, both with SiO2 cover layer, after annealing at 600 ◦C. The graphs represent the azimuthally averaged intensity versus the tilt angle Ψ.

In contrast to this, both ML samples showed a strong intensity in the center of the (101) pole figure and a clear ring at Ψ = 72◦ (see Figure 2c,d). Corresponding to this, the TiAl (110) pole figure contained a ring at Ψ = 54◦. These two measurements confirmed the formation of the γ-TiAl phase.

It is known from the literature that Ti-Al films co-sputtered at room temperature are in general an amorphous mixture of Ti and Al [4,21,22]. The formation of crystalline TiAl phases in amorphous Ti-Al or multilayer Ti/Al thick films in the range of 1.6 μm to 150 μm was investigated by several authors. Illekova et al. studied the activation energy of the phase formation in Ti/Al multilayers with various thicknesses of the individual layer (from 4 to 1000 nm). For a thickness of the individual layer of 20 nm, they derived a value of 169 ± 3 kJ/mol [5]. They also described that for very thin individual layers (4 nm) at first the material becomes amorphous, so that the start of the crystallization is delayed. Senkov et al. analyzed amorphous Ti-Al films and determined an activation energy for the transition from the amorphous state to the first crystalline phase of 315 ± 5 kJ/mol [23]. Although these values were extracted for films with a much larger thickness, the higher activation energy for the formation of the crystalline TiAl phase in amorphous films as compared to ML films can explain the observed difference in the behaviour of the thin films studied in this work.

## *3.2. Film Morphology*

Figure 3 shows the results of the evaluation of the measured AES depth profiles for the amorphous and ML Ti-Al samples in the as-prepared state and after annealing at 400, 600, and 800 ◦C in HV. The composition was calculated from the measured AES spectra using the standard single element relative sensitivity factors (RSF). As can be seen for the co-sputtered films in the as-prepared state (Figure 3a,b), the calculation led to a higher atomic concentration of Ti. In contrast to this, an EDX analysis of a thin lamella of such a sample in the TEM resulted in an atomic composition with slightly more Al than Ti. This deviation of the results can be explained by different actual values of the RSF for the Ti-Al alloy and by a preferential sputtering. The AES results therefore mainly allow a relative comparison of the different samples and annealing states. Besides this, from the analysis of the peak shape and position, the oxidation state of Ti, Al, and Si was derived.

**Figure 3.** Results of the AES measurements of the co-sputtered Ti-Al film, co-sputtered Ti-Al film with SiO2 cover layer, ML Ti/Al film with 10 nm and 20 nm individual layer thickness, both with SiO2 cover layer in: (**a**) the as-prepared state; (**b**) after annealing at 400 ◦C; (**c**) after annealing at 600 ◦C; and (**d**) after annealing at 800 ◦C. In (**d**), the gray contrast of the abscissa in the figures of the alloy samples points out the longer sputtering time as compared to the other graphs. In contrast to this, the sputtering of the ML samples was performed with a higher sputtering energy (2 keV instead of 1 keV), which resulted in a shorter total sputtering time.

In Figure 3a, the results of the measurements of the samples in the as-prepared state are presented. In the uncovered co-sputtered film, a thin Al2O3 layer formed at the sample surface, which can be explained by the lower free energy of the formation of Al oxide as compared to that of TiO2 for pure elements [24]. (It is reported in the literature that in Ti-Al materials the oxide formation depends on the composition and the phases which are present in the material. Rahmel and Spencer determined that Al oxide is more stable than TiO2 in Al rich Ti-Al materials [25].) Across the whole sample thickness, the concentration of Al and Ti was constant.

In the SiO2 covered alloy film as well, a thin Al2O3 layer developed at the interface between the cover layer and the Ti-Al film. For both ML samples, the sequence of the Ti and Al layers was clearly visible. The concentration of both elements did not reach 100 at% in the separate layers and, especially for the film with 10 nm individual layer thickness, a decrease of the amplitudes of the element concentration with increasing sputtering time was seen. These findings can be explained by a partial intermixing of the elements at the interfaces during the sputtering process and by a roughening of the sample surface due to the Ar sputtering, which increases with increasing sputtering time. This roughening led to a simultaneous measurement of different depths, which resulted in an apparent mixture of Ti and Al. In addition, some intermixing can result from the high ion energy during the depositions of the layers. In these ML samples as well, Al2O3 was present below the SiO2 cover layer. The SiO2 layer was deposited at 180 ◦C. Obviously, this temperature is sufficient to initiate a reduction reaction of the SiO2 to Si by Al which forms Al2O3. This effect, which has been widely studied (see, e.g., [26]), was proven for these samples by XPS measurements.

The AES profiles of the samples after annealing at 400 ◦C in HV are shown in Figure 3b. For the uncovered co-sputtered sample, a strong oxide peak was visible at the sample surface, and a constant O signal was measured across the whole sample thickness. However, except for the sample surface, the AES showed Al and Ti only in the elemental and not in the oxidized state, which was derived from the AES peak position. This indicated that the O was solved within the amorphous Ti-Al layer. In contrast to this, in the co-sputtered film with SiO2 cover layer as well as in the ML films no O was measured within the sample. In the ML films, a partly interdiffusion of Ti and Al occurred. In addition, at the Ti-SiO2 interface at the bottom of the film some O was detected in the Ti layer.

After annealing at 600 ◦C, in the co-sputtered film without cover layer the O signal strongly increased. Within the first 5 min of sputtering, Ti was present in the oxidized and for the rest of the measurement in the elemental state. Oxidized Al was found at the sample surface. In the regime between 10 and 20 min of sputtering, Al was present in the elemental state, and the O which was detected there was again solved in the TiAl without forming an oxide. With increasing sputtering time, the amount of oxidized Al increased again, and all Al was present in the oxidized state for the sputtering time between about 35 and 50 min. Afterwards, the part of elemental Al increased again, and in the time regime between about 70 and 85 min only elemental Al was found. Again, O was just solved without forming an oxide. At this temperature, the SiO2 cover layer still successfully acted as a diffusion barrier in the case of the co-sputtered Ti-Al film, which was seen from the constant thickness of the Al2O3 layer below it. However, in the case of the ML samples, the thickness of the Al2O3 interlayer between the SiO2 cover and the TiAl layer increased. At this interfacial region as well, XPS proved the presence of elemental Si. The interdiffusion of the Al and Ti layers in the ML samples was almost completed and only a small variation of the composition remained visible. The annealing at 600 ◦C, however, led to a strong reaction in the Ti/Al ML samples with the SiO2 at the substrate surface. The measurements revealed a layer consisting of elemental Ti and Si on top of the substrate, followed by an Al2O3 layer.

The annealing at 800 ◦C (Figure 3d) led to a degradation of all films and all Al was oxidized. The formed Al2O3 was mainly present in the center of the film. For all samples, at the interface to the substrate a strong Ti and Si signal was measured. In the samples with SiO2 cover layer, Al2O3 was found at the surface of the film. In the case of the co-sputtered film, below this Al2O3, there was a defined layer consisting of Ti and Si. In the ML samples, Ti and Si were distributed across a broader thickness in the upper region of the film, and no oxidized Ti was found at all.

The time necessary to sputter the film increased significantly as compared to the previous measurements. One reason was the low sputter rate of Al2O3. In addition, due to the insulating material, electric charges were accumulated, leading to electric fields which further decreased the sputter rate. Therefore, for the ML samples an increased energy of the Ar ions (2 keV instead of 1 keV) was applied to achieve higher sputter rates.

The AES results showed that the chemical reaction between the Ti-Al film and the SiO2 cover layer and substrate strongly depended on the initial distribution of the elements Ti and Al in the film. In the ML samples, stronger reactions took place at the respective interfaces between the pure Al layer on top and the pure Ti layer at the bottom and the SiO2: a pure Ti layer at the bottom of the sample resulted in a marginal reaction between Ti and Si already at 400 ◦C (see the O signal in the bottom Ti layer) and a strong reaction at 600 ◦C. In contrast to this, in the case of the Ti-Al alloy, such a reaction did not take place at these temperatures. There was also a stronger oxidation of the Al at the interface with the SiO2 cover layer in case of the pure Al layer, as can be seen from the thicker Al2O3 interlayer.

XPS was used to identify the chemical state of the elements in the degraded films. The result of an XPS depth profile analysis of the ML Ti/Al sample with 20 nm individual layer thickness and SiO2 cover layer after annealing at 800 ◦C is shown in Figure 4a. The measurements revealed that Al was only present in the oxidized state (marked by Alox), and the intensity curve follows that of O. Ti was only present in the elemental state (marked by Tiel) and was not oxidized at all. Unoxidized Si was found in the upper and lower region of the film, where its intensity curve was parallel to that of Ti. This behavior indicated the formation of a Ti-Si phase.

**Figure 4.** (**a**) Results of the XPS measurement of the ML sample with 20 nm individual layer thickness; and (**b**) STEM image with dominant chemical contrast, both after annealing at 800 ◦C in HV. In (**a**), the subscript "el" refers to the elemental and "ox" to the oxidized state of the respective element.

In contrast to the ML samples, in the co-sputtered films, the O signal was not parallel to that of Al (see Figure 3d). Around the sputtering time of 30 min, the film without the cover layer showed a strong decrease in the Al, a slightly increasing O, and a maximum in the Ti signal. An analysis of the AES spectral shape revealed that in this region of the film a part of the Ti was oxidized. In the co-sputtered film with SiO2 cover as well, at the sputtering time around 70 min, a stronger O signal as compared to Al was visible. Again, a part of the Ti was oxidized, however, to a much reduced amount as compared to the sample without cover layer.

The reaction between Ti and SiO2 is widely described in the literature (see, e.g., [27,28]). There is a chemical reaction between Ti and SiO2 at their interface, leading to the formation of a Ti silicide. The free O diffuses through the Ti layer, which is possible because of the high O solubility of 34 at% in this material [29]. This solution of O in the bottom Ti layer was already visible for the ML systems after annealing at 400 ◦C (see Figure 3b). During annealing at 600 ◦C, the interface reaction became stronger, and the O which diffused through the Ti layer then reacted with the Al on top of it to Al2O3. Ti not only reacted with the SiO2 of the substrate, but also with the covering SiO2 layer, so that at the film surface Ti-Si was also formed.

In the upper region of the film, a small carbon signal of less than 5 at% was measured by XPS, indicating C which was present in a carbide state. However, most likely the carbide was formed by the Ar sputtering and did not originate from the sample. (More details on the XPS measurement of the Ti-Al samples were published by Oswald et al. [30].)

To get more information on the morphology of this sample, a STEM analysis was performed. A STEM image predominantly showing the chemical contrast is presented in Figure 4b. The EDX analysis confirmed the formation of Al2O3 and the presence of Ti-Si in the upper and lower region of the film. The chemical composition of the Ti-Si grains in the lower region of the film was about Ti60Al40. Close to this composition, there are the two Ti-Si phases: Ti5Si4 and Ti5Si3 [31]. There are reports describing the formation of the Ti5Si3 phase [27,28], and for our samples this phase was confirmed by the small Ti5Si3 (002) peak in the XRD data at 2θ = 40.6◦ in Figure 1c,d.

Figure 5 summarizes SEM images of the FIB cross sections of the different samples in the as-prepared state and after the annealing procedures. In the as-prepared state (Figure 5a), the co-sputtered films showed a homogeneous structure. It was challenging to resolve the 10 nm multilayers; however, the 20-nm Ti and Al layers were clearly visible (dark layers: Ti; brighter layers: Al). After annealing at 400 ◦C, the co-sputtered samples as well as the 10-nm ML film appeared homogeneous. In the 20-nm ML sample, it was still possible to identify the layer structure (Figure 5b).

**Figure 5.** SEM images (inLens, 3 kV) of the FIB cross sections of the co-sputtered Ti-Al film, co-sputtered Ti-Al film with SiO2 cover layer, and Ti/Al ML film with 10- and 20-nm individual layer thickness, both with SiO2 cover layer in: (**a**) the as-prepared state; (**b**) after annealing at 400 ◦C; (**c**) after annealing at 600 ◦C; and (**d**) after annealing at 800 ◦C.

Changes in the microstructure became visible in the co-sputtered film without cover layer after annealing at 600 ◦C. The SEM image showed that darker grains were present in the upper region of the film, and that there are no visible inhomogeneities in the lower region. The dark structures were most likely Ti rich grains. This is in agreement with the AES measurements (Figure 3c), which showed besides Al and O a strong Ti signal in the upper region of the film. In contrast to the uncovered film, the co-sputtered film with SiO2 layer did not possess such inhomogeneities as was expected from the AES measurements, which revealed a homogeneous composition. After annealing at 600 ◦C, in the images of both ML samples, small bright structures were present—in the case of the 10-nm ML in the lower region of the film and in the case of the 20-nm ML additionally in the center region of the TiAl layer. These bright structures were Al2O3 grains on top of the Ti5Si3 layer, which is in agreement with the AES results. In the 20-nm ML films, the AES showed a small O signal during the sputtering time between 40 and 55 min, which was not present in the 10-nm ML sample, caused by the Al2O3 grains that were distributed in the center region of the TiAl layer.

For all samples, strong changes in the morphology appeared after annealing at 800 ◦C (Figure 5d). Irregular formed structures were visible and the film thickness increased significantly. From the evaluation of the EDX data shown in Figure 4 in combination with the AES measurements, it can be derived that the large bright structures were Al2O3 grains. In the case of the uncovered film, these grains were embedded in a Ti and Ti-O matrix, and, in the case of the films with the SiO2 cover layer, the matrix consisted of Ti-Si. In all samples, the interface between the film and substrate was no longer clearly defined and showed a large roughness due to the reaction between Ti and SiO2.

## **4. Conclusions**

This paper reports on the high temperature stability of very thin Ti-Al films. Co-sputtered or multilayered Ti-Al films with a thickness of 200 nm were deposited on thermally oxidized Si substrates, and annealed up to 800 ◦C in HV. Subsequently, they were analyzed regarding their phase formation and degradation processes up to 800 ◦C. In addition, the influence of a SiO2 cover layer was evaluated.

The results show that already after annealing at 400 ◦C co-sputtered Ti-Al films without cover layer started to oxidize. In contrast to this, films with a 20-nm-thick SiO2 cover layer were stable up to 600 ◦C. XRD measurements revealed that in the ML films the γ-TiAl phase formed during annealing at 600 ◦C. For the co-sputtered films, no phase formation was observed at all.

During annealing at 600 ◦C, in the ML samples, a chemical reaction between the Ti and SiO2 of the substrate, but also with the SiO2 cover layer, took place. This reaction led to the formation of Ti5Si3. The free O was solved in the TiAl layer and locally led to the formation of Al2O3. All films were destroyed during annealing at 800 ◦C. Ti silicide was formed to a large extent, and all Al, as well as in the film without cover layer some Ti, was oxidized.

In summary, the results reveal that the deposition of Ti/Al MLs is a prerequisite to achieve the γ-TiAl phase in the very thin films. In contrast to the μm thick TiAl films, which are described in literature, for the thin films, the chemical reaction between the Ti and SiO2 plays a crucial role. On the one hand, the part of the Ti that is chemically bonded to the Si is not available for the TiAl phase formation. On the other hand, the O that is emitted by this reaction leads to the formation of Al2O3 at 600 ◦C within the 10 h of annealing. This effect will be more pronounced for longer annealing times and higher temperatures, and with this contributes to the degradation of the film. For thick films, these processes are negligible, since they only affect a very small part of the total layer. The results also show that a SiO2 cover layer improves the high temperature stability of the TiAl films as compared to samples without cover layer despite the chemical reaction between Ti and SiO2.

To realize a high temperature stability of γ-TiAl thin films, a contact to SiO2 needs to be avoided. This could be achieved by substituting the barrier with another material, e.g., AlN, or by using an additional protection layer. For the application in SAW devices, a high temperature stability of TiAl thin films on other piezoelectric oxide materials such as CTGS substrates also has to be realized.

**Author Contributions:** Conceptualization, M.S., E.L., and S.B.M.; Data curation, M.S., E.L., and S.O.; Funding acquisition, S.B.M.; Investigation, M.S., E.L., and S.O.; Project administration, M.S.; Resources, S.B.M., S.O., and T.G.; Supervision, M.S.; Validation, M.S., S.O., and T.G.; Visualization, M.S.; Writing—original draft, M.S.; and Writing—review and editing, M.S., S.B.M., and T.G. All authors have read and agreed to the published version of the manuscript.

**Funding:** The work was supported by German BMBF under grant InnoProfile-Transfer 03IPT610Y and BMWI under grant 03ET1589 A.

**Acknowledgments:** The authors gratefully acknowledge Thomas Wiek as well as Dina Bieberstein for FIB cuts and TEM lamella preparation and Steffi Kaschube for AES and XPS measurements. Dina Bieberstein is also acknowledged for the support of the texture measurements.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

*Materials* **2020**, *13*, 2039


*3.2. Polyphenolic Compounds Composition*

The total polyphenolic compounds content in PEP ranged from 34.66 to 47.65 g/100 g db and differed due to the drying technique and parameters applied for their dehydration (Table 2) [5]. In general, the highest total content of identified polyphenolic compounds was noted after SPD, which was almost 19% higher when compared to FD, and is regarded as the technique that preserve bioactive compounds the most. Similarly, the highest retention of polyphenolic compounds in sugar-free extracts, submitted to SPD, was noted in case of chokeberry [11] and cranberry [27], which pointed to this dehydration method as being successfully used when the retention of selected polyphenolic compounds is concerned.

Freeze drying (FD); Vacuum drying 40 ◦C (VD 40 ◦C), 60 ◦C (VD 60 ◦C), 80 ◦C (VD 80 ◦C); Spray drying (SPD); different letters (a,b,c,d) within the rows indicate significant differences between samples (*p* ≤ 0.05; LSD Tukey test).

Going into the details, the major group of polyphenolic compounds present in PEP consisted of five identified phenolic acids, among which the chlorogenic and 3-feruoylquinic acids were dominant. The highest retention of these constituents was noted after SPD. As previously observed [5], the drying processes led to the degradation of phenolic acids within the increase of the temperature during VD, except methyl 3-caffeoylquinate. Interestingly, the increase in the temperature during VD up to 80 ◦C, followed by SPD (170 ◦C) resulted in, respectively, 29-, and 16-times higher content of this compound in the powders when compared to those gained after FD. In case of flavonols, processing during which the temperature above 40 ◦C (VD 40 ◦C, VD 60 ◦C, VD 80 ◦C and SPD) caused a strong degradation of quercetin-3-*O*-galactoside, the application of such conditions caused an increase in the content of quercetin-3-*O*-glucoside when compared to FD. This might be connected with the thermally-induced release of this constituent during drying. In general, the SPD process resulted in better retention of flavonols being almost 20% higher when compared to FD. In the current study, three anthocyanins

had been identified and their content followed the same patterns as the above-mentioned groups of polyphenolic compounds.


**3.1 Synthesis of silane-coupled Nanosilica and its incorporation into chitosan matrix**

**Figure 1** illustrates the interaction model between chitosan, nanosilica, and silane in membranes. At the final stage of silylation process that is epoxy groups deformation (ring-opening) on silane organofunctional group end chain, silane form two hydroxyl groups (–OH) which interacts with the amine group (–NH2) and and hydroxyl groups (-OH) in chitosan to form hydrogen bonds that could form a good interface interaction of chitosan and silane-coupled nanosilica network. Thus forming groups Si–OH via hydrogen bonds [5, 10] and siloxane groups (Si–O–Si) via oxane bonds [32].


**Author details**

Ingrid Dijkgraaf1,2\*, Stijn M. Agten1 , Matthias Bauwens2 and Tilman M. Hackeng1

1 Department of Biochemistry, Maastricht University, The Netherlands

2 Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands

\*Address all correspondence to<EMAIL_ADDRESS>
© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


**7. References**

Accurate Measurement of Systemic

Surg 125(1): 71-78.

119(3): 525-533.

136(5): 1207-1214.

48(9): 1859-1864.

Cardiovasc Res 4(1): 23-30.

Care Med 31(4): 1235-1240.

Ann Thorac Surg 78(4): 1389-1396.

Thorac Surg 77(5): 1671-1677.

anastomosis." Crit Care Med 33(5): 984-989.

Oxygen Consumption in Ventilated Children with Congenital Heart Disease 315

Kawamura, M., O. Minamikawa, et al. (1980). "Combined use of phenoxybenzamine and

Kendrick, A. H., J. West, et al. (1988). "Direct Fick cardiac output: are assumed values of

Kitaichi, T., F. Chikugo, et al. (2003). "Suitable shunt size for regulation of pulmonary blood

LaFarge, C. G. and O. S. Miettinen (1970). "The estimation of oxygen consumption."

Laitinen, P. O. and J. Rasanen (1998). "Measured versus predicted oxygen consumption in

Li, J., A. Bush, et al. (2003). "Measured versus estimated oxygen consumption in ventilated

Li, J., A. Hoschtitzky, et al. (2004). "An analysis of oxygen consumption and oxygen delivery

Li, J., A. Hoskote, et al. (2005). "Effect of carbon dioxide on systemic oxygenation, oxygen

Li, J., I. Schulze-Neick, et al. (2000). "Oxygen consumption after cardiopulmonary bypass

Li, J., J. Stokoe, et al. (2004). "Continuous measurement of oxygen consumption during

Li, J., G. Zhang, et al. (2007). "Comparison of the profiles of postoperative systemic

Li, J., G. Zhang, et al. (2008). "Energy expenditure and caloric and protein intake in infants following the Norwood procedure." Pediatr Crit Care Med 9(1): 55-61. Li, J., G. Zhang, et al. (2008). "Carbon dioxide--a complex gas in a complex circulation: its

Li, J., G. Zhang, et al. (2008). "Significant correlation of comprehensive Aristotle score with

Li, J., G. Zhang, et al. (2008). "The influence of systemic hemodynamics and oxygen

Li, J., G. Zhang, et al. (2006). "Adverse effects of dopamine on systemic hemodynamic status

procedure: a pilot study." Circulation 116(11 Suppl): I179-187.

procedure." J Thorac Cardiovasc Surg 136(1): 123-128.

J Thorac Cardiovasc Surg 135(1): 83-90, 90 e81-82.

cardiopulmonary bypass." Br Heart J 43(4): 388-392.

oxygen consumption acceptable?" Eur Heart J 9(3): 337-342.

children with congenital heart disease." Heart 80(6): 601-605.

dopamine for low cardiac output syndrome in children at withdrawal from

flow in a canine model of univentricular parallel circulations." J Thorac Cardiovasc

patients with congenital heart disease: the validity of predictive equations." Crit

in euthermic infants after cardiopulmonary bypass with modified ultrafiltration."

consumption, and blood lactate levels after bidirectional superior cavopulmonary

surgery in children: determinants and implications." J Thorac Cardiovasc Surg

cardiopulmonary bypass: description of the method and in vivo observations." Ann

hemodynamics and oxygen transport in neonates after the hybrid or the Norwood

effects on systemic hemodynamics and oxygen transport, cerebral, and splanchnic circulation in neonates after the Norwood procedure." J Thorac Cardiovasc Surg

total cardiac output during the early postoperative period after the Norwood

transport on cerebral oxygen saturation in neonates after the Norwood procedure."

and oxygen transport in neonates after the Norwood procedure." J Am Coll Cardiol

Charpie, J. R., M. K. Dekeon, et al. (2001). "Postoperative hemodynamics after Norwood palliation for hypoplastic left heart syndrome." Am J Cardiol 87(2): 198-202. Chiara, O., P. P. Giomarelli, et al. (1987). "Hypermetabolic response after hypothermic

Cori, C. F. and K. W. Buchwald (1930). "Effect of continuous injection epinephrine on the

Davies, N. J. and D. M. Denison (1979). "The measurement of metabolic gas exchange and minute volume by mass spectrometry alone." Respir Physiol 36(2): 261-267. Davies, N. J. and D. M. Denison (1979). "The uses of long sampling probes in respiratory

Ensinger, H., T. Weichel, et al. (1993). "Effects of norepinephrine, epinephrine, and

Fick, A. (1870). "U ¨ ber die Messung des Blutquantums in der Herzventrikeln."

Fomon, S. J., F. Haschke, et al. (1982). "Body composition of reference children from birth to

Fowler, M. B., E. L. Alderman, et al. (1984). "Dobutamine and dopamine after cardiac

Gaynor, J. W., W. T. Mahle, et al. (2002). "Risk factors for mortality after the Norwood

Gentles, T. L., K. Gauvreau, et al. (1997). "Functional outcome after the Fontan operation:

Gentles, T. L., J. E. Mayer, Jr., et al. (1997). "Fontan operation in five hundred consecutive

Gilbert, E. M., M. T. Haupt, et al. (1986). "The effect of fluid loading, blood transfusion, and

Grollman, A. (1932). The Cardiac Output in Man in Health and Disease. Springfield, Illinois,

Haupt, M. T., E. M. Gilbert, et al. (1985). "Fluid loading increases oxygen consumption in septic patients with lactic acidosis." Am Rev Respir Dis 131(6): 912-916. Hayes, M. A., A. C. Timmins, et al. (1994). "Elevation of systemic oxygen delivery in the

Hoffman, G. M., N. S. Ghanayem, et al. (2000). "Venous saturation and the anaerobic

Hoskote, A., J. Li, et al. (2004). "The effects of carbon dioxide on oxygenation and systemic,

threshold in neonates after the Norwood procedure for hypoplastic left heart

cerebral, and pulmonary vascular hemodynamics after the bidirectional superior

treatment of critically ill patients." N Engl J Med 330(24): 1717-1722.

syndrome." Ann Thorac Surg 70(5): 1515-1520; discussion 1521.

cavopulmonary anastomosis." J Am Coll Cardiol 44(7): 1501-1509.

carbohydrate metabolism, basal metabolism and vascular system of normal man."

dopamine infusions on oxygen consumption in volunteers." Crit Care Med 21(10):

Sitzungsberichte der physikalisch-medicinischen Gesellschaftzu Wurtzberg: XVI–

surgery: greater augmentation of myocardial blood flow with dobutamine."

factors influencing late morbidity." J Thorac Cardiovasc Surg 114(3): 392-403;

patients: factors influencing early and late outcome." J Thorac Cardiovasc Surg

catecholamine infusion on oxygen delivery and consumption in patients with

cardiopulmonary bypass." Crit Care Med 15(11): 995-1000.

mass spectrometry." Respir Physiol 37(3): 335-346.

age 10 years." Am J Clin Nutr 35(5 Suppl): 1169-1175.

procedure." Eur J Cardiothorac Surg 22(1): 82-89.

sepsis." Am Rev Respir Dis 134(5): 873-878.

Circulation 70(3 Pt 2): I103-111.

discussion 404-395.

114(3): 376-391.

Charles C Thomas.

Am J Physiol(95).

1502-1508.

XVII.

Accurate Measurement of Systemic

discussion 185-176.

121(6): 1033-1039.

Cardiovasc Surg 124(3): 435-441.

Circulation 96(11): 3934-3942.

the dog." Anesth Analg 57(1): 37-41.

Diagn 43(4): 372-380.

118(Suppl).

167-168.

2235.

376-385.

Biochem Cell Biol 36(11): 2098-2104.

Oxygen Consumption in Ventilated Children with Congenital Heart Disease 317

Salim, M. A., C. L. Case, et al. (1995). "Pulmonary/systemic flow ratio in children after

Sano, S., S. C. Huang, et al. (2009). "Risk factors for mortality after the Norwood procedure

Schulze-Neick, I., J. Li, et al. (2001). "Pulmonary vascular resistance after cardiopulmonary

Schulze-Neick, I., J. Li, et al. (2002). "The endothelin antagonist BQ123 reduces pulmonary

Sell, H., Y. Deshaies, et al. (2004). "The brown adipocyte: update on its metabolic role." Int J

Shanahan, C. L., N. J. Wilson, et al. (2003). "The influence of measured versus assumed

Shekerdemian, L. S., A. Bush, et al. (1997). "Cardiopulmonary interactions in healthy

Shekerdemian, L. S., A. Bush, et al. (1997). "Cardiopulmonary interactions after Fontan

Tweddell, J. S., G. M. Hoffman, et al. (1999). "Phenoxybenzamine improves systemic oxygen

Vandam, L. D. and J. A. Fox (1998). "Adolf Fick (1829-1901), physiologist: a heritage for anesthesiology and critical care medicine." Anesthesiology 88(2): 514-518. Wernovsky, G., D. Wypij, et al. (1995). "Postoperative course and hemodynamic profile

Wessel, H. U., D. Rorem, et al. (1969). "Continuous determination of oxygen uptake in

Westenskow, D. R., W. S. Jordan, et al. (1978). "Correlation of oxygen uptake and

Wolf, A., M. J. Pollman, et al. (1998). "Use of assumed versus measured oxygen consumption

Zhang, G., H. Holtby, et al. (2008). "Aortic atresia is associated with an inferior postoperative

bidirectional Glenn anastomosis." Cardiol Young 13(2): 137-142.

negative pressure ventilation." Heart 78(6): 587-593.

using right ventricle to pulmonary artery shunt." Ann Thorac Surg 87(1): 178-185;

bypass in infants: effect on postoperative recovery." J Thorac Cardiovasc Surg

vascular resistance after surgical intervention for congenital heart disease." J Thorac

uptake of oxygen in assessing pulmonary vascular resistance in patients with a

children and children after simple cardiac surgery: the effects of positive and

operations: augmentation of cardiac output using negative pressure ventilation."

delivery after the Norwood procedure." Ann Thorac Surg 67(1): 161-167; discussion

after the arterial switch operation in neonates and infants. A comparison of lowflow cardiopulmonary bypass and circulatory arrest." Circulation 92(8): 2226-

sedated infants and children during cardiac catheterization." Am J Cardiol 24(3):

cardiovascular dynamics during N2O-fentanyl and N2O-thiopental anesthesia in

for the determination of cardiac output using the Fick principle." Cathet Cardiovasc

systemic, cerebral and splanchnic oxygen transport status in neonates with hypoplastic left heart syndrome after the Norwood procedure. ." Circulation

cavopulmonary anastomosis." J Am Coll Cardiol 25(3): 735-738.

Li, J., G. Zhang, et al. (2006). "Inclusion of oxygen consumption improves the accuracy of

Li, J., G. Zhang, et al. (2007). "Profiles of hemodynamics and oxygen transport derived by

Lindahl, S. G. (1989). "Oxygen consumption and carbon dioxide elimination in infants and

Lundell, B. P., M. L. Casas, et al. (1996). "Oxygen consumption in infants and children

Maher, K. O., C. Pizarro, et al. (2003). "Hemodynamic profile after the Norwood procedure with right ventricle to pulmonary artery conduit." Circulation 108(7): 782-784. Mair, D. D., D. J. Hagler, et al. (1990). "Fontan operation in 176 patients with tricuspid

Maxwell, G., S. Crompton, et al. (1985). "The effect of dopamine upon oxidative metabolism

Merin, G., D. Bitran, et al. (1977). "The hemodynamic effects of dopamine following

Migliavacca, F., G. Pennati, et al. (2001). "Modeling of the Norwood circulation: effects of

Mora, G. A., C. Pizarro, et al. (1994). "Experimental model of single ventricle. Influence of carbon dioxide on pulmonary vascular dynamics." Circulation 90(5 Pt 2): II43-46. Moukarzel, A. A., J. S. Salas, et al. (2003). "Estimate of specific energy expenditure of fat-free

Nisbet, H. I., T. L. Dobbinson, et al. (1973). "Oxygen uptake in ventilated children during

Ohye, R. G., L. A. Sleeper, et al. (2010). "Comparison of shunt types in the Norwood procedure for single-ventricle lesions." N Engl J Med 362(21): 1980-1992. Oudemans-van Straaten, H. M., P. G. Jansen, et al. (1996). "Increased oxygen consumption

Penny, D. J., T. Sano, et al. (2001). "Increased systemic oxygen consumption offsets improved

Powers, S. R., Jr., R. Mannal, et al. (1973). "Physiologic consequences of positive end-

Rosenblum, R. and J. Frieden (1972). "Intravenous dopamine in the treatment of myocardial

Rutledge, J., A. Bush, et al. (2010). "Validity of the LaFarge equation for estimation of oxygen

expiratory pressure (PEEP) ventilation." Ann Surg 178(3): 265-272.

dysfunction after open-heart surgery." Am Heart J 83(6): 743-748.

years--A revisit." American Heart Journal 160(1): 109-114.

methoxyflurane anaesthesia." Can Anaesth Soc J 20(3): 334-346.

endotoxemia." Intensive Care Med 22(4): 294-300.

children during anaesthesia and surgery." Br J Anaesth 62(1): 70-76.

during heart catheterization."  Eur J Pharmacol 116(3): 293-297.

cardiopulmonary bypass." Ann Thorac Surg 23(4): 361-363.

procedure." J Thorac Cardiovasc Surg 131(5): 1099-1107.

Thorac Cardiovasc Surg 133(2): 441-448.

Suppl): IV164-169.

280(5): H2076-2086.

51(4): 206-210.

Med 27(9): 1518-1525.

arterial and venous oxygen saturation interpretation after the Norwood

using continuous measured oxygen consumption after the Norwood procedure." J

atresia. Results and a proposed new index for patient selection." Circulation 82(5

shunt size, vascular resistances, and heart rate."  J Med Liban

after cardiac surgery is associated with the inflammatory response to

oxygen delivery during dobutamine infusion in newborn lambs." Intensive Care

consumption in ventilated children with congenital heart disease younger than 3

**14**

*Japan*

Toshiyuki Itoi

**Myocardial Lactate Metabolism in Children**

*Department of Pediatric Cardiology and Nephrology,*

*Graduate School of Medical Science, Kyoto Prefectural University of Medicine*

**with Non-Cyanotic Congenital Heart Disease**

It is well recognized that main energy source for myocardium is fatty acids (Wisneski et al.,1987, Lopaschuk et al.,2010). However, in failing heart or in hypertrophied heart, fatty acid oxidation ability was reported to be impaired and, on the contrary, carbohydrates were preferred to use for provision of energy demand (Stanle et al.,2005,Lopaschuk et al.,1992). The fetal heart is exposed to relatively high lactate concentrations. Immediately after birth, plasma lactate concentrations decrease. In the immature heart, *lactate dehydrogenase (LDH) is* predominated by the M type isozyme, as higher activity, resulting in greater lactate production from pyruvate (Brooks et al., 1985). This requires greater NADH levels than seen in the adult heart. The dominance of glycolytic flux in immature hearts leads to accumulation of lactate to a greater extent than is seen in adult hearts during profoundly

It has been shown that, in the isolated perfused rat heart, lactate significantly contributes to acetyl-CoA formation more than glucose. When fatty acid oxidation is activated, pyruvate dehydrogenase (PDH) activity is suppressed by increase of the NADH/NAD+ ratio followed by an enhancement of lactate production from accumulated pyruvate. As a result, lactate is released from myocardium even under aerobic status (Brooks et al., 1985). Immediately after birth, fatty acids are not the major energy substrate in newborn hearts, although the capacity of the heart for oxidization of fatty acids rapidly increases. Of interest,

Patho-physiology of congenital heart defects (CHD) is very wide ranging from the right ventricular (RV) volume overload and/or pressure overload to the left ventricular (LV) volume overload and/or pressure overload. CHD with left-to-right shunt is basically a noncyanotic status. However, the myocardial cells may be in the milieu of relatively low oxygen because of relative decreased of coronary circulation from hypertrophy. Despite the evidence that lactate may be an important fuel for myocardial energy metabolism, there is remarkably little information on the lactate utilization in immature hearts especially in CHD. Lactate plays the other important role as a regulator of cellular redox state. *The redox state described in this chapter is defined as the balance of NADH/NAD+ in the myocardium.* The cytosolic NADH/NAD+ ratio in most tissues is enhanced by activation of glycolysis. If lactate dehydrogenase (LDH) activity is high such as in heart, the lactate/pyruvate (L/P)

lactate is also important ATP provider in newborn heart (Lopaschuk et al. 1991).

**1. Introduction**

hypoxic states (Brooks et al., 1985).

Zhang, G. M., M; Holtby, H; Cai,S; Van Arsdell,G; Li,J (2008). "Blood Glucose Negatively Correlates with Systemic Hemodynamics and Oxygen Transport and Cerebral Oxygenation in Neonates after the Norwood Procedure." Circulation 118(Suppl.): 913.


**8.2 DTS2 System Conceptual Model**

• Output material product assets {[OMPA (i, j)]} and Output material product assets {[OMP (i, j)]} linguistic set content is being transferred to {MAC: [LM

The data transfer from microprocesses internal metrics to macroprocesses is

• The {MIC: IM:[DEV (i, j)]} and {MIC:[IM:TOOL (i, j)]} linguistic content is being transferred to MAC: [FM(CA (i, j)]}, {MAC: [FM(SA (i, j)]}, and {MAC:

• The {MIC: IM:[DEV (i, j)]} and {MIC:[IM:TOOL (i, j)]} linguistic content is being transferred to {MAC: [LM(WA (i, j)]}, MAC: [LM(PR (i, j)]}, MAC: [LM

• The {MIC: IM:[HR (i, j)]} linguistic content is being transferred to {MAC: [LM

• After having completed the previous step, the extracted data and data segments or fragments are transformed to data structure, which might be accepted by application, which enables generating adequate creative

**8. Data Transfer System MAC versus CE Processes (DTS2 System)**

As mentioned above, the DTS Systems operates within two directions. It provides data transfer from CE Processes to MAC Processes, while the MIC Processes play a role of mediator, when running the data transfer between CE and MAC Processes and that type of transfer is covered by DTS1 Subsystem, the data transfer between MAC and CE processes is covered by DTS2 Subsystem. We shall describe a

In general, the creative economy processes (CE Processes) are closely related to social and economic processes, which represent external environment and provide transfer of signals or data to set of macroprocesses, which represent an outgoing point for data transfer concerned to social and economic requirements related to CE and MIC processes. On one hand, when considering the social processes, a set of cultural and art processes play a role of principle importance. On the other hand, when considering the economic processes the research and development processes create basis from creative economy point of view, while the logistics, and personal management processes play a role of principle importance for the research and development processes and for production processes as well. Both of the abovementioned processes (social and economic) provide transfer of data to MAC processes, which are necessary from external and internal source analysis and they play an important role, when generating values closely related to KPI indicators postu-

However, the KPI indicator values postulated at national economy level are being transferred to MIC processes, where their decomposition related to appropriate MIC process busines levels (strategic, tactic and operational) and play an important role at BPMIV setting and evaluation of performance related to adequate processes running within MIC processes set. However, the KPI indicators play an important role MIC and CE process management as well, while cultural heritage

(WA (i, j)]}, MAC: [LM(PR (i, j)]}, MAC: [LM(WAPRE.

*Operations Management - Emerging Trend in the Digital Era*

(WA (i, j)]}, MAC: [LM(PR (i, j)]}, MAC: [LM(WAPRE.

running in the following steps:

economics strategies.

lated at national economy level.

**116**

**8.1 DTS2 System structure and functionality**

structure and functionality of DTS2 Subsystem in that section.

(WAPRE.

[GM(EA (i, j)]} linguistic sets

As mentioned above (see also Section 7.1), the DTS System – Conceptual Model is a standardized system denoted as DATRA\_09 Data Transfer Conceptual Model, which should provide a bi-directional data transfer. On one hand, from Creative Economy Business Processes (CEP Processes) to Microprocesses (MIC Processes) and (MIC Processes) and from Microprocess to Macroprocesses (MAC Processes) and on the other hand, we have to consider the data transfer from macroprocesses, throughout microprocesses up to CEP Processes as well, while DTS System – Conceptual Model consists of four subsystems as shown in **Figure 4**. However, the social and economic processes create significant elements of DTS System external environment and generate appropriate data important for functionality of MAC Processes, which provide services for KPI indicator generation [22] within an appropriate firm or company business strategy creation [25, 26].

However, there is data and information generated as a result of text [27, 28] and image sematic analysis [29, 30], as well, while some of those algorithms might be applied, when providing analysis of the firm or company external and internal resources before getting started business strategy creation and KPI generation too. Subsequently, the KPI indicators are being decomposed [22] and assigned to adequate MIC Processes organization units and their metrics [24] item values are being set simultaneously. After having completed the above-mentioned action the management of MIC and CEP Processes might be started, where logistic, personal financial and research and development management play a role of principle importance as well, while the production processes are significant for MIC process management and cultural heritage creation and management are significant from CEP Processes point of view.

The principle layout of DTS2 System Conceptual Model is shown in **Figure 7**.


**Author details**

S.O. Ylmaz\* and M. Aksoy *Department of Material and Metallurgical Engineering Frat University Elaziğ, Turkey*

<sup>\*</sup> Corresponding Author

C. Ozel, H. Phtl and M. Gür

*Department of Mecahnaical Engineering Frat University Elaziğ, Turkey*

#### **5. References**

[1] Metal powder Industries Federation: "*Powder metallurgy Equipment Manuel*" New York, 1968.

**Chapter 2**

© 2013 Bahçe and Ozel, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2013 Bahçe and Ozel, licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**Experimental Investigation of the Effect**

**of Machining Parameters on the Surface**

**(BUE) in the Drilling of Al 5005**

Additional information is available at the end of the chapter

drilling process of aluminum and its alloys [2,3]

of the optimization of machining process [7,8].

Erkan Bahçe and Cihan Ozel

http://dx.doi.org/10.5772/56027

**1. Introduction**

**Roughness and the Formation of Built Up Edge**

Aluminum is one of the metals, besides iron and steel, which are widely used in many industrial fields such as aviation, navigation and automotive. The most considerable reasons why aluminum is so widely used are: i) it is light, ii) its alloys have higher strength than the construction steel, iii) it has high heat and electrical conductivity. Because of these excellent characteristics, the usage of aluminum as engineering material has an ever-increasing importance in several technological fields [1,2]. Although aluminum is widely used, there are many problems such as tool abrasion, burr formation and poor hole surface quality in

The surface quality, which is one of these problems, is quite important for the efficient working of machine parts. The structure of a machined surface is one of the most important criteria in terms of quality, and tribological properties of the machined surface are considerably affected from the surface tissue. Generally the surface quality is characterized with surface roughness. Surface roughness is an important factor which must be considered not only in the conventional subjects of tribology such as abrasion, friction and lubrication but also in different fields such as sealing, hydrodynamics, electrical and heat conductivity. Surface roughness is mainly affected during the machining process by cutting parameters such as cutting speed, feed rate and depth of cut [4,5,6]. If these parameters are not chosen convenient, the surface roughness increases. This situation creates a notch effect and results in crack initiation, decrease in fatigue strength and corrosion resistance. So, the characterization and measurement of surface roughness has a great important in the sense