| Titanium is widely used as artificial joints, bone and dental implant for its well physical properties and biocompatibility. Surface modification methods of titanium include sandblasting, acid etching, alkali heat treatment, micro-arc oxidation, plasma spraying, sputtering coating and so on. Preparing hydroxyapatite coating on the surface of titanium is the most interested method. However, the surface overall coating is easily shed from matrix during the implant process, which could lead to implant failure. On the other hand, plasma spraying, ion implantation and sputtering coating methods are complex operation and expensive equipment.In this paper, traditional and simple operation methods, such as sol-gel-sintering coating, alkali treatment, were used to titanium material surface modification, and apatite polycrystalline were formed in the simulation of body fluids (SBF). A certain density bioactive sites were prefabricated on the surface of metal titanium to replace the brittle interface between the overall coating and matrix. It could directly guided bone tissue combining with titanium materials and achieved osseointegration.Coating was prepared by sol-gel-sintering method, calcium nitrate tetra hydrate, sodium nitrate, TEOS (tetraethoxysilane), ethanol and sodium borate were used to prepare the sol solution, and then the titanium sheets were dipped in the sol solution and drew up and sintered. The perfect technological parameter were dipping time 10min, sintering start temperature 100℃, and predrying time 20℃, heating rate 20℃/min, sintering temperature 650℃, holding time 30min and cooling time 10min. The Ti-Si-Ca-Na-0 coating that was uniformity and cover complete without cracking, grain size about 200nm was prepared on titanium surface. The Ti-Si-Ca-Na-0 coating was immersed in SBF, coating was dissolved after 7 days, slender crack appeared and apatite was not formed. The results show that preparing density oxide layer on titanium surface to induce apatite deposition was failure.Titanium surface was treated by sand blasting and alkaline corrosion, and then immersed in SBF to induce apatite deposition. The effect of sodium hydroxide concentration and, average surface roughness, sand blasting and pre-calcified on apatite crystal deposition was studied. The results show that:(1) Titanium treated by 5mol/L sodium hydroxide solution immersed in SBF for 2 days, globular apatite which average particle size was approximately 3.15μmand grain distance was 0-6μm has formed. However, titanium treated by 3mol/L sodium hydroxide solution immersed in SBF for 2 days, apatite was not appeared. After 3 days, globular apatite which average particle size was approximately 4.81μm and grain distance was 0-16μm was appeared. (2) Immersed for 3 days, a certain density apatite druse was formed on the surface of titanium. Apatite made up of tabular crystal, which surface were fluffy and filled with micropore, were formed on the surface of S5 polished by 500 mesh sandpaper and S8 polished by 800 mesh sandpaper. Apatite made up of granular crystallization, which surfaces were smooth and structure were densification, were formed on the surface of S10 polished by 1000 mesh sandpaper. After calculating, the results got that S5:average surface roughness of titanium surface Ra=0.646μm, average grain size of apatite R=3.23μm, surface coverage r=72.5%.S8: Ra=0.348μm, R=0.82μm, r=12.14%. S10:Ra=0.188μm, R=4.81μm, r=50.53%. (3) Titanium treated by sand paper burnish-sand blasting-acid and alkali corrosion immersed in SBF to induce apatite deposition. The results show that:sand blasting introduced impurities Si and Al. Immersed in SBF for 3 days, the surface corrosion pit of sample P was filled and globular particle appeared. The surface of sample G pre-calcified was smooth and grain was wrapped in it. Immersed in SBF for 3 days, compared to samples P, surface sediments of sample G were thicker. Pre-calcification accelerated the rate of hydroxyapatite nuclei formation. Immersed in SBF for 7 days, the ratio of Ca and P on the surface of sample P was 2.78, and the ratio of Ca and P on the surface of sample G was 2.89, they were all more than 1.67 which is the ratio of Ca and P for hydroxyapatite. Large silicon atoms were detected and Si-O-Si group were confirmed by Raman spectrum. It shows that Ca was reacted with Si-O-Si group and other substance contained Ca was formed except for apatite.
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