RESEARCH ARTICLE
Nanoindentation Study of Phase-pure Highly Crystalline Hydroxyapatite Coatings Deposited by Microplasma Spraying
Arjun Dey 1, *, Anoop Kumar Mukhopadhyay 2
Article Information
Identifiers and Pagination:
Year: 2015Volume: 9
Issue: Suppl 1-M5
First Page: 65
Last Page: 74
Publisher ID: TOBEJ-9-65
DOI: 10.2174/1874120701509010065
Article History:
Received Date: 15/4/2014Revision Received Date: 31/5/2014
Acceptance Date: 31/8/2014
Electronic publication date: 27/2/2015
Collection year: 2015
open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.
Abstract
The present contribution has originated from a critical biomedical engineering issue e.g., loosening of metallic prostheses fixed with poly(methylmethylacrylate) (PMMA) bone cement especially in the case of hip joint replacement which ultimately forces the patient to undergo a revision surgery. Subsequently surgeons invented a cementless fixation technology introducing a bioactive hydroxyapatite (HAp) coating to the metallic implant surface. A wide variety of different coating methods have been developed to make the HAp coating on metallic implants more reliable; of which ultimately the plasma spraying method has been commercially accepted. However, the story was not yet finished at all, as many questions were raised regarding coating adherence, stability and bio-functionality in both in vitro and in vivo environments. Moreover, it has been now realized that the conventional high power plasma spraying (i.e. conventional atmospheric plasma spraying, CAPS) coating method creates many disadvantages in terms of phase impurity; reduced porosity limiting osseointegration and residual stresses which ultimately lead to inadequate mechanical properties and delamination of the coating. Further, poor crystallinity of HAp deposited by CAPS accelerates the rate of bioresorption, which may cause poor adhesion due to quick mass loss of HAp coatings. Therefore, in the present work a very recently developed method e.g., low power microplasma spraying method was utilized to coat HAp on SS316L substrates to minimize the aforementioned problems associated with commercial CAPS HAp coatings. Surgical grade SS316L has been chosen as the substrate material because it is more cost effective than Ti6Al4V and CoCrMo alloys.
