Investigation of corrosion behavior and surface properties of plasma sprayed HA/Sr reinforced coatings on CoCr alloys

Abstract

The cobalt-chromium alloys have superior mechanical properties (wear resistance and stiffness) as compared to stainless steels and titanium alloys, and are commonly used as orthopedic implants. Nevertheless, the unnecessary release of the ‘Co’ and ‘Cr’ ions from CoCr embeds can steer to harmful health issues that results in hypersensitivity and inflammatory reactions. The objective of the present study was to improve the surface properties and corrosion resistance of CoCr alloy plasma-sprayed with pure Hydroxyapatite (HA) and HA reinforced Strontium (Sr) powder. In HA/Sr coatings, Sr was mixed with HA at three levels (HA + 4 wt % Sr, HA + 8 wt % Sr and HA + 12 wt % Sr). The electrochemical technique was used to study the corrosion behavior of coated and uncoated samples in the ringer solution. Various surface parameters such as microhardness, surface roughness, and wettability were analyzed. In this study, it was examined that on increasing the reinforcement of Sr in HA coating, corrosion resistance of samples improved simultaneously. The outcomes revealed adequate surface roughness was obtained and there is a rise in surface hardness after reinforcement. The contact angle of coated samples shows a hydrophilic nature that plays a major role in increasing the clinical success of implantation.