Friction and wear behaviors of biodegradable Mg-6Gd-0.5Zn-0.4Zr alloy under simulated body fluid condition

The friction and wear behaviors of biodegradable Mg-6Gd-0.5Zn-0.4Zr (wt%, GZ60K) alloy were evaluated under simulated body fluid (SBF) condition using ball-on-disk configuration and compared with those under dry sliding condition. The results show that under dry sliding and SBF conditions, the friction coefficient declines with increasing applied load and keeps stable with prolonging sliding time. The friction coefficient of the alloy effectively decreases in SBF as compared to dry sliding due to lubrication caused by SBF. The real wear rates under SBF condition are lower than those under dry sliding condition for each parameter. Nevertheless, the nominal wear rates are higher in SBF which are attributed to the more mass loss caused by corrosion but not wear. Both the nominal wear rate in SBF and the dry sliding wear rate increase with increasing applied load, and they decline firstly and then keep stable with prolonging sliding time. It is concluded that the wear of the alloy is restricted by the SBF, but the corrosion of the alloy is aggravated by the wear.