CAN THE STANDARDS FOR TESTING DOUBLE TAPER HIP PROSTHESIS BUILD UP THE CLINICAL SITUATION?

Abstract

Particulate (TiC, TiB2 or Si3N4) reinforced Ti composites were produced by vacuum sintering (at 1400°C for 2 h). Ti+TiC composites could be sintered to high fractional densities (>93%), even at high TiC loadings (e.g., 40 volume percent (vol%)). No reactions were observed to occur between the Ti and TiC. By contrast, the Ti and TiB2 and Ti and Si3N4 reacted to form composites consisting of Ti, TiB and TiB2 and α-Ti(N), Ti5Si3, Ti3Si, and Ti2N, respectively. As a consequence, Ti was consumed and/or the reaction products intrinsically generated porosity during sintering. These composites were more difficult to consolidate via solid state sintering, particularly at higher volume fractions. Despite the porosity, the composites were more wear resistant (pin-on-drum abrasive wear against 100 μm garnet particles) than unreinforced Ti, with the exception of the Ti+2.5 vol% TiB2 and Ti+≤10 vol% TiC composites. The ranking of microhardness and abrasion wear resistance of the composites was as follows: (hardest, most wear resistant) Ti+Si3N4 (i.e., α-Ti(N), +Ti5Si3, Ti3Si, and Ti2N)≫Ti+TiB2≫Ti+TiC (softest, least wear resistant). The microhardness coupled with the apparent strength of the chemical interface that developed between the constituent composite phases was responsible for the observed wear behavior.