Fretting behavior of cortical bone against titanium and its alloy

Under the lubrication by the imitated human physiological solution, the fretting behaviors of flat cortical bone were investigated against titanium (TA2) and its alloy (TC4) ball counterpart. The friction logs and coefficients were recorded automatically. The worn surfaces of cortical bone were analyzed by means of laser confocal scanning microscopy. The results show that friction logs transform from partial slip directly to gross slip without mixed regime. The wear depths of bone generally increase with the friction coefficient. The worn scar area on bone is a little bit larger than that on ball surface. The wear depths on Ti ball were only several micrometers, which were much less than those on bone. The comparison of fretting behaviors between the bone-TA2 pair and bone-TC4 pair were of particular interest. The friction coefficient of bone-TC4 pair is higher than that of bone-TA2 pairs. The maximum wear depth on bone against TA2 is about 40% the value of that on bone against TC4. The wear adaptability of bone-TA2 pair is better than that of bone-TC4 pair. The abrasive wear and delamination related to the microstructure of bone are observed on the wear scar of cortical bone.