Structures and Properties of Zr--N Films Prepared by ECR-Microwave Plasma Source Enhanced Direct-Current Magnetron Sputtering Under Different N₂ Partial Pressures

ZrN thin films were prepared on 45# steel by using ECR-microwave plasma source enhanced dc magnetron sputtering. The increase of the N₂ partial pressure P_N2 leads to phase transitions from ZrN and an orthorhombic ZrN_x phase to an amorphous phase. At P_N2=1.1×10^-2Pa to 4.5×10^-2Pa, the films contain both ZrN and ZrN_x (a=0.3585, b=0.4443, c=0.5798nm). At P_N2=5.0×10^-2Pa, the film shows a strong tendency towards the amorphous phase. The N concentration at different P_N2 varies from 7.73 to 66.96% according to electron probe analysis. The microhardness of the samples, varying from 19.82GPa to 26.73GPa, first increases and then decreases with increasing P_N2. The hardest sample has a wear rate of about 4.5×10^-5mg/min. The property changes are relative to the film structure due to different N₂ partial pressures.