Abstract
It has been proposed that the oxide film on metallic bearing surfaces improves its corrosion resistance and decreases wear. Influence of dissolved oxygen in the lubricating liquid containing principal constituents of synovial fluid on wear characteristics of Co-Cr-Mo alloy used in a metal-on-metal artificial hip joint has been investigated by using a pin-on-plate wear machine. Decrease in the concentration of dissolved oxygen caused the wear to decrease, in which the concentration was approximately the same value in vivo. The material properties of the bearing surface are probably controlled by the oxygen concentration. The friction coefficient increased in the low oxygen concentration. This indicates that the decrease in the oxygen concentration makes the adhesion between the bearing surfaces increase. The increase in the adhesion leads to the high frictional force. The high adhesion and frictional force affected work hardening and refinement of the bearing surface, so that the wear was decreased.
