Effect of DC power on the thickness, hardness and adhesion strength of Ti-51 at% Ni coated Ti/TiN

The coating of Ti/TiN was successfully deposited on Ti-51 at% Ni substrates by using direct current (DC) magnetron sputtering technique and the effect of different sputtering power on the thickness, surface hardness and adhesion strength of the coatings were studied. The microstructural characterization was carried out using scanning electron microscope (SEM), energy-dispersive X-ray (EDX) and X-ray diffractometer (XRD). The coating thicknesses were detected and measured using SEM. The surface hardness test was performed using microhardness tester, and the adhesion strength was carried out by scratch testing. The results showed that the TiN crystallites growth orientation, thickness, surface hardness and adhesion strength are influenced by sputtering power. As power increased from 300 W to 370 W, peaks at (111), (200) and (311) increased while peaks at (200) and (222) decreased, substrate hardness increased by 53.42%, thickness increased from 2.278 μm to 2.389 μm, and adhesion strength also increased from 3000 mN to 3998 mN. Meanwhile, a decrease in thickness, hardness, adhesion strength, all the peaks and total disappearance of peak (222) were all noticed at 440 W.