Coating of hydroxyapatite on magnesium AZ91D through chemical conversion
The following paper presents what has been done in the project entitled "Biodegradable coatings on AZ91D, assessment of performance in simulated physiological fluid", in which three types of coatings are investigated to reduce the corrosion of the metal in a biological medium. In this first part of the work, it was carried out a chemical conversion by immersion in order to deposit hydroxyapatite (HAp) on the surface of the magnesium alloy parts, manufactured by powder metallurgy. For this purpose a hydrothermal treatment of the samples was conducted in EDTA-Ca and KH2PO4 solution for 4h. The coatings were observed by confocal microscopy and tested through surface adhesion test and hydrogen release test in 0.9 %w/v. NaCl solution at 37 °C. It was obtained a conversion on the surface with encouraging results. A deposition of HAp on the surface and a 95,4% decrease in the corrosion rate of coated samples were obtained and it is expected to be further improved. For this, the investigation must continue, delving into the factors that influence this behavior.