Fretting wear mechanism of bones against a plasma-sprayed hydroxyapatite/copper coating on a tantalum substrate

A hydroxyapatite (HAp)/copper (Cu) coating was deposited on a Ta substrate by plasma spraying to mitigate the fretting wear of bones. It was found that the HAp/Cu coating significantly reduced the fretting slip of Ta at the Ta-bone interface. The friction coefficient of the HAp/Cu coating-bone frictional pair (1.14) was much higher than that of the Ta-bone frictional pair (0.71). The HAp/Cu coating significantly mitigated the fretting wear of bones by forming a protective layer on the fretting interface and reduced the wear rate from 0.031 mm3/N·mm to 0.0029 mm3/N·mm.