Unraveling the role of sintering temperature on physical, structural and tribological characteristics of ball milled Co28Cr6Mo biomaterial based alloy

This work aim to investigate the effect of sintering temperature (950 to 1250 °C) on structural, physical, tribological properties of nanobiomaterial Co28Cr6Mo alloy for total hip prosthesis obtained by high Energy ball milled. Several techniques such as density, porosity, microhardness, and Young's modulus were used to assess the mechanical and physical characteristics. Tribological behavior were conducted using a ball-on-plate type Oscillating tribometer, under different applied loads (2, 10 and 20 N), under a wet condition using hank's solution to simulate human body fluid. SEM, EDS and XRD analysis results, showed that Co-Cr-Mo alloy samples sintered exhibit the same phases created by the Co element. The alloy sintered at 1250 °C displayed the highest micro-hardness value in terms of mechanical characteristics (386.75 HV0.1. The porosity changes from 17% to 10% and endorse a higher change in Young's modulus around 61.84 and 92.5 GPa for samples sintered beteew 950 and 1250°C, respectively,. A remarkable decrease in the wear rate and volume values is obtained for the sample sintered at 1250 °C (32.1610-3 μm3 (N.m)-1) compared to other samples sintered at 1150 and 1250°C. Under wet tribological conditions, the abrasive and adhesive wear mechanisms were identified as the main degradation mechanisms for all sintered samples.