Sinterability Of Hydroxyapatite Compacts Prepared By Cold Isostatic Pressing For Clinical Applications

Abstract

The effect of cold isostatic pressing (CIP) on the sinterability of synthesized hydroxyapatite (HA) powder was investigated. The starting powder was initially uniaxially die-pressed at about 1.3–2.5MPa to form disk and rectangular green compacts. Two batches of green samples were prepared, i.e. one batch was in the as-compacted state (Un-CIP) and another batch samples was subjected to cold isostatic press at 200 MPa (CIP). The latter samples exhibited a linear shrinkage of ∼16% prior to sintering. All the samples were sintered in air at temperatures ranging from 700°C to 1400°C. The densification behaviour of HA was evaluated in terms of linear shrinkage, phase stability, bulk density, Vickers hardness and Young’s modulus. The results revealed that green samples subjected to cold isostatic pressing exhibited better sinterability and possessed excellent mechanical properties. This effect is more pronounced particularly for the low temperature sintering regime i.e. ≤ 1100°C.