Research Of The Character On The Ceramic Coating On The Titanium Alloy By Micro Oxidation And The Process Of MAO

The titanium alloy has better biocompatibility, corrosion resistance and mechanical compatibility, but it lacks bioactivity. So it has important value in research and clinic application to modify the titanium's surface for improving its bioactivity. In this study, the bioceramic coating was formed on the surface of Ti6Al4V substrate using the device of Micro-arc Oxidation imported from Russia. The effect of technical parameters on the morphology and microstructure composition and properties of the ceramic was studied. Experiment of the ceramic immersion in simulated body fluid (SBF) was processed, sedimentation mechanism and growth process on surface of Hydroxyapatite (HA) were discussed.The bioceramic coating which contained calcium phosphate compound was formed on the surface of Ti6Al4V in the electrolytes composing of Ca(CH3COO)2.H2O-NaH2PO4 2 H2O and (NaPO4)6- Ca(CH3COO)2.H2O. The results showed that: the coating was the ceramic intermixture which was porous and firmly combined with the titanium alloy substrate and the ceramic coating consists of rutile, anatase and phase such as CaTiO3. The porosity of the ceramic coating and Ca/P were changed with the treating time and the concentration of the electrolytes. The thickness and coarseness of the ceramic coating increased while the treating time and the consistency of the electrolytes increasing.The salt spray test was used to test the corrosion resistance .The result showed that: the corrosion resistance was mainly determined by the treating time and the concentration of the electrolytes .Simulate body fluid (SBF) cultivation is the most elementary experiment method to measure the material's biological activity. The ceramic coating had been immersed in SBF for several days. The results showed that the ceramic coating made by Micro-arc Oxidation technology on the surface of titanium alloy could be acquired Hydroxyapatite (HA) through SBF cultivation. The content of the calcium phosphate compound in the coating were increased. Hydroxyapatite (HA) preferential nucleated and grown up in some defective location such as crack and pore. The coating surface firstly formed into Hydroxyapatite (HA) crystal like sphericity or geanular, and the grown up as agglomerated or rod shape. After immersion, the Ca/P in the ceramic coating increased to 1.70, which approached to the Ca/P 1.67 in human skeleton.