Extremely low wear rates in hip joint bearings coated with nanocrystalline diamond

Abstract

A hip joint wear simulator is used for the first time to evaluate the performance of acetabular linersand femoral heads made of silicon nitride ceramic coat edwithnano crystallinediamond(NCD),grownbya hot filament chemical vapor deposition (HFCVD) method. Wear is assessed by gravimetry, bywhich volume and linear wear are estimated.Even with only one millioncyclesoftest,avery stimulating finding is the extremely low wear rate of the head after the diamond polish ingrunningin step,of about 0.005mm3/million cycles(Mc).Thiscorrespondstoalinearwearof0.08 μm/Mc, oneorderofmagnitude better than the best value currently known for ceramic on ceramichipjoints.Small scaleabrasionis found as the dominant wear mechanism.