Applying Nanocomposite Coatings to Improve Orthopedic Alloys by Using Multiple Flame Spray

Abstract

Due to their excellent mechanical and biocompatibility characteristics, CoCr-based alloys are frequently employed in orthopaedic implant applications. It is necessary to maximize their general characteristics, corrosion resistance, and ion release. Despite several benefits, coating with torch flame spray has weaker adherence. As a result, powder metallurgy was employed to combine Si and Nb elements with CoCr alloys. CoCrNb and CoCrSi alloys were sprayed with multiple torch flames to apply two different kinds of Nano-coatings (A: 75% HAP+ 25% SiC, and B: 75% Zeolite+ 25% ZrO2). In two samples, alloying elements Nb and Si were added at a concentration of 5 wt.%. Various characterization methods are employed, such as field emission scanning electron microscopy (FESEM) or energy dispersive X-ray spectroscopy (EDS), an ion release test, atomic absorption spectroscopy (AAS), a wear test, corrosion measurement, atomic force microscopy (AFM), and an adhesion strength test. According to the results, coating (type A) and (type B) increase the wear resistance of CoCr alloy. The zeolite+ZrO2 (type B) and HAP+SiC (type A) coating layers act as barriers to the release of Co and Cr ions from CoCr alloys. There were varying degrees of roughness in the coated samples, which resulted in corrosion pitting. According to tensile pull-out tests, the two-torch flame spraying technique provided a stronger bond with the substrate than the single-torch flame spraying technique. In general, CoCrSi coated type B are the best to be implanted where the cytotoxicity is 0% in the human body, thus an excellent biocompatibility.

Keywords

• cocrnb
• cocrsi
• coating
• hap+sic
• zeolite+zro2