Corrosion resistance hydroxyapatite assessment and tricalcium beta phosphate coating, deposited on stainless steel low carbon vacuum melted

Abstract

316 stainless steel low carbon vacuum melted, used for surgical implants, has good corrosion resistance, but it is degraded in the body fluids presence, generating problems for the receiver, therefore it is necessary to apply coatings that improve their biocompatibility. In the current work hydroxyapatite and tricalcium beta phosphate coatings were applied on 316 stainless steel substrates, by the radio frequency magnetron sputtering technique, with a 2 m thickness for possible biomedical applications. The coatings characterization was performed, using scanning electron microscopy, found the Ca/P ratio of 1.639 for hydroxyapatite and 1.515 for phosphate, the friction coefficient was additionally evaluated by pin on disk tribometer, with a lower coefficient of beta tricalcium phosphate in relation to hydroxyapatite. The corrosion evaluation was carried out using the electrochemical polarization technique Tafel, in Ringer lactate, as simulated biological fluid. It was observed that the coatings improve the steel electrochemical behavior and between the two coatings the one that best behaves is the tricalcium beta phosphate, with a corrosion low rate.