Wear and corrosion properties of in-situ grown zirconium nitride layers for implant applications

摘要

AbstractZirconium (Zr) and its alloys are considered as promising materials for implant applications due to their excellent biocompatibility. However, the poor tribological properties of Zr are limiting its widespread applications. Therefore, in this investigation thermal nitriding of laser processed Zr was carried out with an aim to improve its wear and corrosion properties for potential wear resistant implant applications. The influences of nitriding temperature and time on the nitride layer thickness, phase constituents, wear and corrosion properties of nitrided Zr layer were studied. The Zr samples were nitrided at 600°C and 800°C for 2 and 6h in flowing nitrogen. The results demonstrated that the nitriding temperature had relatively stronger influence on the nitride layer thickness, wettability, hardness and wear resistance than nitriding time. In general, the nitride layers found to contain ZrN and ZrO2as major phases and Zr2N and Zr7O8N4as minor phases. The nitride layer thickness increased from 5±0.7μm to 26±5μm with increase in the nitriding temperature and time. Nitriding also enhanced the wettability and passivity of Zr. The samples nitrided at 600°C for 2h resulted in noblest Ecorrof ?130mV vs SCE with Icorrof 0.001μA/cm2in Hank's balanced salt solution. Lowestin vitrowear rate of 4.4×10?7mm3/N·m was recorded, against Al2O