Study on mechanical and wear characterization of novel Co30Cr4Mo biomedical alloy with added nickel under dry and wet sliding conditions using Taguchi approach

This paper investigates the effect of nickel particulate on mechanical behavior and sliding wear performance of novel Co30Cr4Mo alloy for orthopedic hip implant application with and without an introduction of distilled water (i.e. both dry and wet conditions) medium. The mechanical behavior is examined by the micro-hardness tester and the compression testing machine, while the wear performance is analyzed through a pin-on-disc tribometer where the samples slide against a counter disc made up of hardened alloy steel (EN-31) under different operating conditions at room temperature. Scanning electron microscope, atomic force microscopy, and X-ray diffraction are used to examine the surface morphology, worn surface profile, and cross-sectional microstructure of the fabricated alloy (Co30Cr4Mo) composite. In this study, at the beginning, steady state experimental analysis is carried out to find the volumetric wear loss and friction coefficient by varying the sliding velocity and normal load, respectively. After obtaining the steady state results, the Taguchi design of experiment has been conducted followed by statistical analysis of variance to identify the significant factor setting for obtaining better performance output. From the analysis, it is found that by increasing the nickel wt.%, the hardness and the compression strength of the fabricated alloy composites are increased. Furthermore, the fabricated alloy composite with 1 wt.% Ni shows the better wear resistance under different operating conditions in both dry and wet media. This study will give an idea for hip implant application but not direct replacement of human joints. In future, this study may be extended in more detail for biomedical applications for replacement of either human hip implant or animal implant, respectively.