Interfacial diffusion reaction and mechanical characterization of 316L stainless steel-hydroxyapatite functionally graded materials for joint prostheses

By Muhammad Akmal and Fazal Ahmad Khalid and Muhammad Asif Hussain
Published in Ceramics International NULL 2015

Abstract

Functionally graded materials (FGMs) of 316L stainless steel (316L) matrix with the reinforcement of hydroxyapatite (HA) were fabricated successfully by a pressureless sintering technique for bioimplants. Hydroxyapatite content was varied among the layers of \FGMs\ up to 20 wt% with 5 wt% gradient. Two types of \FGMs\ were prepared with the same composition in the discrete layers. However, micro- and nano-sized hydroxyapatite was used to reinforce the 316L matrix in two different \FGMs\ under similar conditions of compaction and sintering. \FGMs\ with nano-sized \HA\ (nHA) exhibited better densification than the \FGMs\ prepared with micro-sized \HA\ (mHA). The interdiffusion of chromium along the 316L and \HA\ interface was observed, which improved the interfacial bonding and the \FGMs\ properties. The hardness increased due to strong interfacial boundary for second layer, then due to dominant factor of porosity hardness decreased for succeeding layers of FGMs. Potentiodynamic polarization analysis of both \FGMs\ are also presented and discussed in response to the particle size of \HA\ and interfacial phase produced.

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