Development of nc-W2N/a-Si3N4 Hard Coating

Abstract

In this work, the pure nc-W2N and nc-W2N/a-Si3N4 nanocomposite films were deposited at 200 degrees C substrate temperature by magnetron sputtering. The effect of Si3N4 target power on microstructural and mechanical properties of the films were studied. The XRD results showed the formation of cubic nc-W2N in both pure W2N and nc-W2N/a-Si3N4 film. A significant broadening of (111) reflection was present in nc-W2N/a-Si3N4 film with an increase in Si3N4 power. The broadening of peaks suggested a decrease in the average crystallite size (approximately 21 to 2 nm) in the films. Surface morphology showed that grains of W2N were diminished by amorphous Si3N4 with an increase in Si3N4 target power (50-90W). Elemental analysis confirms the presence of W, Si and N elements in the films. The hardness and elastic modulus were improved and found optimum at 50W then reduced at 90W Si3N4 power. The highest hardness and elastic modulus achieved were 22.13 GPa and 263.04 GPa respectively.