pure metals are made of atoms or ions.
pure metals are made of atoms or ions.
are pure metals made of atoms or ions?
atoms
by adding another element to a metal, differences in the size of the atoms create internal stresses in the lattice of the metallic crystals; stresses that often enhance its properties. for example, the combination of carbon with iron produces steel, which is stronger than iron, its primary element. the electrical and thermal conductivity of alloys is usually lower than that of the pure metals. the physical properties, such as density, reactivity, young's modulus of an alloy may not differ greatly from those of its base element, but engineering properties such as tensile strength, ductility, and shear strength may be substantially different from those of the constituent materials. this is sometimes a result of the sizes of the atoms in the alloy, because larger atoms exert a compressive force on neighboring atoms, and smaller atoms exert a tensile force on their neighbors, helping the alloy resist deformation. sometimes alloys may exhibit marked differences in behavior even when small amounts of one element are present. for example, impurities in semiconducting ferromagnetic alloys lead to different properties, as first predicted by white, hogan, suhl, tian abrie and nakamura.
alloy
the common co-cr alloy production requires the extraction of cobalt and chromium from cobalt oxide and chromium oxide ores. both of the ores need to go through reduction process to obtain pure metals. chromium usually goes through aluminothermic reduction technique, and pure cobalt can be achieved through many different ways depending on the characteristics of the specific ore. pure metals are then fused together under vacuum either by electric arc or by induction melting. due to the chemical reactivity of metals at high temperature, the process requires vacuum conditions or inert atmosphere to prevent oxygen uptake by the metal. astm f75, a co-cr-mo alloy, is produced in an inert argon atmosphere by ejecting molten metals through a small nozzle that is immediately cooled to produce a fine powder of the alloy.
cobalt-chrome