Microstructure, mechanical and biological properties of laser cladding derived CaO-SiO_2-MgO system ceramic coatings on titanium alloys

摘要

To improve the bioactivity of titanium alloy (Ti-6Al-4V), laser cladding derived CaO-SiO2-MgO system ceramic coatings were successfully fabricated on the surface of titanium alloy. The effect of MgO content on microstructure, mechanical and biological properties of laser cladding coatings was analyzed. The mechanism of the formation of apatite on the cladding layer in simulated body fluid (SBF) was discussed. The laser cladding derived CaO-SiO2 ceramic layer is mainly composed of CaTiO3, CaO, alpha-Ca-2(SiO4), SiO2 and TiO2. The main phases of the ceramic layer contained different MgO content are all CaTiO3. MgO refines the microstructure of the ceramic layer, and slightly reduces the average hardness of the ceramic layer. The wear resistance decreases with the increase of MgO content. The compounds containing Si in the cladding layer are the main components that induced apatite formation. After soaking in simulated body fluid (SBF) for 21 days, the apatite layer is formed on the coating surface. The hemolysis test, in vitro cytotoxicity test and systemic toxicity test demonstrate that the cladding coating not cause hemolysis reaction, and have no toxicity to cell and living animal, which shows the cladding coating has good biocompatibility.