A tribological study of the petaloid surface texturing for Co-Cr-Mo alloy artificial joints

To improve the tribological performance of Co-Cr-Mo alloy artificial joints, a petaloid surface texturing is prepared through laser pulse ablation. The tribological influence of such surface texturing is studied by pin-on-plate tests. A mixed lubrication numerical model is also developed for elucidating the possible mechanisms deduced from the experimental data. Results illustrate that the petaloid surface texturing can effectively reduce friction and wear of Co-Cr-Mo artificial joints. Analysis suggests that the relevant mechanisms involved in the tribological improvement of such surface texturing are: (i) the micro-reservoirs formed between petals in the petaloid textures amplifying the secondary lubrication effect; (ii) the increase of film thickness between friction interfaces; and (iii) the creation of micro-hydrodynamic pressure. However, the micro-hydrodynamic action only plays a minor role since artificial joints usually work under the operating condition of low lubricant viscosity, low speed, and heavy load.