Effect of Zr ion implantation on the hardness and wear-resistance of NiTi shape memory alloys

The paper reports on the effects of Zr ion implantation parameters,incident dose and incident current, on the surface composition,morphology,hardness and wear resistance of NiTi shape memory alloys.When Zr ions are implanted in the NiTi alloy surface,their content presents Gaussian distribution but the Ni content is reduced in the surface.After Zr ion implantation,groove structures appear on the surface,and the nano-hardness,Young’s modulus and the microhardness of the surface increase obviously.Friction and wear experiments show that Zr-ion implantation reduces the initial friction coefficient and significantly prolongs the time maintaining a lower initial friction coefficient. The width and depth of wear tracks for Zr-NiTi alloy decrease by 30%to 50%and 28%to 50%,respectively.The choice of appropriate ion implantation parameters can get the best wear resistance of NiTi alloys.