Surface roughness testing
The surface roughness of the materials was tested using a contact stylus profilometer (SJ- 210 Surface roughness tester Mitutyoyo Japan). Each specimen was fitted to the specimen holder, where the surface was to be measured in the horizontal direction; then, the specimen holder moved in a vertical direction up to the specimen surface, touching the measuring tip. Device calibration is done according to the manufacturer's instructions before use Testing parameters:Measuring distance 4 mmMeasuring Speed 0.5 mm/s. Returning 1 mm/sMeasuring force 0.75 mNStylus profile: tip radius 2-micron, tip angle 60 degreeEvaluation parameter Ra values expressed in microns