Study On Preparing Ca- And P-containing Ceramic Coating On Ti-6Al-4V By Micro-arc Oxidation

Ti-6Al-4V alloy is used widely in the field of medicine at the present time. Ti-6Al-4V alloy is an ideal biomedical material owing to its low density, high specific strength and innocuity. Ti-6Al-4V can be used as implantation materials, and it is of the elastic modulus similar to that of bone of human being, excellent corrosion resistance, enough strength and toughness when it is implanted in body. So Ti-6Al-4V can be used in the position of body, in which it need to bear big force. But Ti-6Al-4V in body can separate out little V and Al ions, which reduce the cell adaptability of this alloy and maybe are harmful to body. Furthermore, because of the big differences of properties and structure between Ti-6Al-4V and bone and the lack of the biological activity, only simple mechanical bond can be formed between Ti-6Al-4V and bone after being implanted in body, and the fibrous tissue film can't be formed on the surface of bone, which makes the interface bond unstable and the implantation loose or easy to fall off. So the surface of Ti-6Al-4V should be treated before it is implanted in body.By micro-arc oxidation (MAO) technique, a ceramic coating, which is mainly composed of oxide and bonds strongly with matrix, can be obtained on the surface of some nonferrous metals and their alloys. This oxide film includes two layers: the compact inner layer and the rough and porous outer layer. The inner layer is firmly adhered to the substrate and the outer layer is porous, which is beneficial for the biological performance of the implants. So using microarc oxidation technique on Ti alloys, not only the surface hardness of Ti alloys can be improved, but also the biocompatibility of Ti alloys can be increased. The previous research results showed that the ceramic coating on the surface of Ti alloys by microarc oxidation could contain Ca and P elements, which are the basic component of bone, through adjusting the composition of electrolyte. So the biological activity of Ti alloys could be improved. The porous rough layer containing Ca and P element with...