Abstract
The purpose of this study is to characterize wear of ultra-high molecular weight polyethylene (UHMWPE) by means of two predominant factors; exposure time and contract pressure, using a UHMWPE pin / Co-Cr-Mo alloy disk test. The wear rate of the UHMWPE under 2.0 or 12.0MPa decreased with the prolongation of the exposure time until it became a constant value, because the disk was replenished with a sufficient adsorbed film of the synovial fluid constituents, which may reduce abrasive wear and adhesive wear. The wear rates under 20.0MPa were not influenced by the exposure time, and were lower than those of 2.0 or 12.0MPa. It is possible that the rubbing motion under the high contact pressure caused the film formation to deteriorate. This indicates the occurrence of adhesion of UHMWPE being formed on the disk at asperity levels. The adhesive UHMWPE may function as a transferred film, which reduces the wear rates.
