Improving wear resistance of Zr-2.5Nb alloy by formation of microtextured nitride layer produced via laser surface texturing/plasma nitriding technology

Zr-Nb alloys are highly of interest of being used as metallic implants due primarily to its excellent biocompatibility and MRI compatibility. Unfortunately, the widespread is severely limited by their low hardness and poor wear resistance. Combination of Laser surface texturing (LST) and plasma nitriding (PN) technology was performed to improve the tribological properties of Zr-2.5Nb alloy by producing a microtextured nitride layer. The influences of different procedure (LST/PN, PN/LST, PN, and LST) on the surface microhardness and wear resistance of Zr-2.5Nb alloy were well analyzed by laser confocal microscope (LSCM), scanning electron microscopy (SEM), X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) equipped with energy dispersive spectrometer (EDS). The results indicated that the Zr-2.5Nb alloy processed by LST/PN composite technology presented the highest microhardness and lowest wear rate. The Zr-2.5Nb alloy processed with LST or PN/LST presented a much higher wear rate than PN or LST/PN, indicating that the microtraps produced by LST covered with a nitride layer produced by PN exhibited excellent wear resistance. The composite technology, especially LST/PN provide a great potential in improving wear resistance for metal joint implants.