Study On Ultrasonic Micro - Arc Oxidation Biological Coating Of Nano - SiO 2 / TiO 2 Particles

Pure magnesium and magnesium alloys would be degradable bone repair materials due tothe biologictivity and biodegradability, but the relative high in vivo degradation rate limits theirapplication. Therefore, the corrosion of magnesium alloys should become a key problem to besolved. The surface modification of magnesium alloys was one of the main ways to solve theprombles. The corrosion resistance could be improved by the micro-arc oxidation(MAO)coatings using micro-arc oxidation technology on the magnesium alloy. However, magnesiumalloy micro-arc oxidation coating of magnesium alloy still exit certain problems. The nanobiological coatings on the pure magnesium was fabricated by the ultrasion-micro-arc oxidationtechnology in silicate electrolyte solution with n-SiO2/n-TiO2powers. Under the effect of hightemperature plasma, n-SiO2/n-TiO2nanoparticles filled pore and micro cracks. The goodbiological coatings degradation can be controlled. The corrosion resistance can be improved andthe degradation speed can be controlled of the preparation coating after took silane treatmentand in different concentrations of nano particles sol.SEM, XRD, the coating thickness gauge, the contact angle tester, scratch tester and thepin-disc friction and wear tester were investigated to analyze the morphology, the phasestructure,thickness, the contact angle, adhesion force and friction coefficient of thecoatings. The corrosion resistance and corrosion resistace mechanism of coatings were analyzedby using dynamic polarization curves. The morphology, the weight loss and the composition ofthe coatings immersed in SBF were discussed.The pores on the coatings reduced from an average of5μm to an average of3μm withadding n-SiO2/n-TiO2particles in silicate electrolyte solution. The solution containing n-SiO2/n-TiO2particles were obtained7.5g/L and4.8g/L respectively. The coating thickness increasedfrom10.26μm to13.32μm/14.16μm. The surface contact angle changed from hydrophilic tohydrophobic surface. The coatings and the substrate bonding strength increased from4.9N to7.4N/7.2N respectively. The friction coefficient decreased from1.1to0.6/0.4respectively. Thecorrosion potential increased from-1.513V to-1.513/-1.490V respectively, and the corrosioncurrent decreased an order of magnitude. The sample with the coatings immersed in SBFshowed that the weight became from loss to gain. The pure magnesium sample with MAOcoating generationed a kind of bone apatite after immersed in SBF. The coatings after the silicohydride treatment with the concentrations of7.5g/L n-SiO2and4.8g/L n-TiO2respectively.When the concentration of n-SiO2/n-TiO2were2g/L and1g/L respectively in solution, thecorrosion potential of the super hydrophobic coating increased to-1.382V/-1.402V respectively.bonding strength of the super hydrophobic coating increased to3.6N/4.3N respectively.wear-resisting coefficient of the coating increased to0.4/0.3respectively.