Synthesis and characterization of plasma sprayed functional gradient bioceramic coating for medical implant applications
By Singh, Jarnail; Chatha, Sukhpal Singh; Singh, Hazoor
Published in Ceramics International
Ceramics International
2020
Abstract
The dissolution of plasma-sprayed hydroxyapatite (HA) coating in physiological media is complex and involves numerous factors. It is generally believed that the highly crystalline HA coatings are beneficial for long-term stability, whereas amorphous layers dissolve more quickly and promote early biointegration. In the present study, the functionally gradient coating (FGC) was formulated in three successive layers over Ti6Al4V alloy using an atmospheric plasma spray (APS) process. At the inner layer, the titania (TiO2) bond coat is applied to enhance adhesion strength. In the middle layer, crystalline hydroxyapatite (HA) coating was deposited to provide long-term stability. In contrast, the outer amorphous layer of as-sprayed HA coating was assumed to promote the early implant bonding with host bone. The crystallinity level of the middle HA layer was increased by post coating heat treatment at 700? C for 1 h. There is an improvement in microhardness value after heat treatment from 276.6