Bioactivity Glass Coatings Elaborated by Plasma Spraying from 31SiO2-11P2O5-(58-x) CaO- X MgO Powders

In this study, bioactive glass powders were prepared from four different types of oxides (SiO₂, P₂O₅, CaO and MgO). These oxides were mixed, melted, milled and sieved to produce two compositions of a 31SiO₂-11P₂O₅-(58-x)CaO-xMgO system. The thermal stability of the powders was determined by DTA. The powders were sprayed onto AISI 316L stainless steel and TA6V titanium alloy substrates using a F4MB Sulzer Metco gun. The microstructure of the powders and the obtained coatings was examined by SEM. XRD was used to identify the crystalline phases in the powders and coatings. The hardness and fracture toughness of the coatings were determined by a Vickers micro-indentation test. The bioactivity was determined by the dissolution and subsequent formation of a hydroxyapatite layer by contacting the coatings with simulated body fluid for 1, 9 and 15 days. The hydroxiapatite layer was determined by X ray diffraction and SEM (EDS).