Open AccessThe possibilities of atmospheric plasma-spraying application to obtain hydroxyapatite coatings on the stainless steel samples
Author(s) -
Darka Mihailović,
S Aleksandra Patarić,
P Zvonko Gulisija,
V Zoran Janjušević,
D Miroslav Sokić
Publication year - 2013
Publication title -
hemijska industrija
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.147
H-Index - 19
eISSN - 2217-7426
pISSN - 0367-598X
DOI - 10.2298/hemind120910001m
Subject(s) - materials science , microstructure , coating , biocompatibility , porosity , metallurgy , titanium , corrosion , ultimate tensile strength , biomaterial , composite material , nanotechnology
For decades, the standard metallic materials for hip implants, besides the 316LVM stainless steel, were titanium- and cobalt/chromium-based alloys. Although bioinert, due to their corrosion resistance, they are not biocompatible. Contemporary surgical implants are not made just of bioinert metal anymore, but with deposited bioactive hydroxyapatite (HAp) coating. Hydroxyapatite is chemically identical with the mineral constituent of bones and teeth, what besides its biocompatibility provides bioactivity as well. The HAp limitations are, however, weak tensile strength and low fatigue resistance for long term loadings, if used alone. This is the reason for HAp to be deposited onto the surgical implant, and to enable its bioactivity, what means intergrowth with bones, and therefore the long-lasting and mechanical stable non-cemented prosthesis. This is important predominantly because the need for such prostheses for younger population, and a better life quality. There are several contemporary techniques that have been used for deposition of these coatings onto the metal implant. The possibilities of atmospheric plasma-spraying for obtaining the stable HAp coatings on the 316LVM stainless steel, ordinary used as a standard material for hip implants production are presented in this paper. The coatings of a commercially available hydroxyapatite powder were plasma-sprayed onto the specimens of medical grade 316LVM stainless steel under various operating conditions. The optical microscopy was used for microstructure and porosity characterization, while coating morphology and Ca/P ratio were analyzed using SEM equipped with EDX. Coating microstructure varied from a porous to a glassy structure, depending on operating conditions applied and coating thickness. Coating porosity was determined to be at the lower required limit requested for the bone-coating intergrowth possibility, but nevertheless adhesion measurements showed good results. The Ca/P ratio was determined for both as-deposited coatings and after ageing in distilled water for various time and temperature combination