Wear and corrosion characterization of single and multilayered nanocrystalline tantalum coatings on biomedical grade CoCrMo alloy

Osteolysis caused by the worn-offparticles of polyethylene (PE), and corrosion of CoCrMo head have been two major concerns in total hip replacement as they lead to its early failure. Here we report on the development of a Ta multilayered coating to improve the corrosion resistance of CoCrMo and minimize the wear rate of PE. Deposition of single-layered and multilayered Ta coatings was carried out at ambient temperature utilizingmagnetron sputtering with deposition pressure ranging from 0.3 Pa to 1.9 Pa. The hardness and Young's modulus of the Ta coatings ranged from 8 to 21 GPa and from 179 to 288 GPa, respectively. Excellent adhesion was observed on the Ta coatings deposited at a high deposition pressure. The PE wear rate was 4% lower when sliding against the Ta multilayered coating than with the uncoated sample. Furthermore, the Ta multilayered displayed a 61% greater corrosion resistance than the uncoated CoCrMo alloy. The results indicate that Ta coatings have great potential for artificial joint applications.