A QUANTITATIVE STUDY OF THE SINTERING AND MECHANICAL-PROPERTIES OF HYDROXYAPATITE PHOSPHATE-GLASS COMPOSITES

Previous work has shown that small additions of a phosphate glass (CaO -P2O5) can significantly enhance the sinterability and strength of hyd roxyapatite. However, there are no quantitative phase analyses availab le for these materials which would provide indicators of biocompatibil ity and resorbability. Similarly, there is little information availabl e about the mechanical properties, especially with high glass addition s. In this study, the effects of sintering hydroxyapatite with phospha te glass additions of 2.5, 5, 10, 25, and 50 wt.% are quantified. Each composition was sintered over a range of temperatures, and quantitati ve phase analysis was carried out using XRD. In addition, the microstr uctures were studied using RLOM and SEM, and mechanical properties (Vi ckers hardness, K-IC, and MOR) measured. These results may be used to indicate which compositions and processing conditions may provide mate rials suitable for use in hard tissue replacement. Composites containi ng up to 10 wt.% glass additions formed dense HA/TCP composite materia ls possessing flexural strength and fracture toughness values up to 20 0% those of pure HA. The HA/TCP ratio was strongly dependent on the pe rcentage glass addition. Higher glass additions resulted in composites containing P-TCP together with large amounts of alpha- or beta-calciu m pyrophosphate, and having similar mechanical strengths to pure HA. 0 1998 Published by Elsevier Science Ltd. All rights reserved.