The sliding wear of UHMWPE against zirconia in saline containing proteins

A study has been made of the sliding wear behaviour of ultrahigh molecular weight polyethylene (UHMWPE) against a smooth counterface of partially stabilized zirconia (PSZ) in distilled water and in saline solution containing small additions of synovial fluid and up to 15% of albumen. The results have shown that the addition of proteins to the lubricating medium leads to a lowering of wear rates and the production of finer debris particles. The mode of material removal from the polymer surface of the tests conducted in distilled water is through debonding at the interface of the deformed surface layers and bulk material and the production of sheet-like debris. In protein-containing solutions, these debonded volumes also appear in the form of fine fibres and stringers. No fully coherent transfer layer formed on the ceramic counterface during tests, although those conducted in albumen-containing solutions were more uniform than those found during testing in distilled water. The observed phenomena have been explained in terms of the interaction of the protein with both the polymer and ceramic counterface. (C) 1997 Elsevier Science S.A.