Preparation And Properties Of Hydroxyapatite Nanorod Coating On Titanium Alloy Surface

It is a common method to improve the biological properties of titanium and titanium alloy by preparing hydroxyapatite coating on titanium and titanium alloy surface.In this study,the morphology of hydroxyapatite coating on the base surface of anodized and two hydrothermal methods was studied,and the effect of barium titanate mixture on the ferroelectric properties of hydroxyapatite coating was explored.First,the titanium dioxide nanotube coating is prepared on the titanium alloy substrate surface by anodized method,and then the titanium alloy substrate is put into the mixed aqueous solution of sodium hydroxide and calcium hydroxide for hydrothermal reaction at different times,to prepare the titanium dioxide-calcium titanate coating,The hydrothermal time was 0.5h?1.0h?1.5h?2.5h?3.0h?4.0h?5.0h.Then,the deposition of calcium titanate was observed separately,to study the effect of different hydrothermal times on calcium titanate deposition,and to determine the most suitable hydrothermal time for the subsequent experiments.Finally,the second hydrothermal reaction of the titanium alloy substrate into the aqueous solution of sodium hydroxide and sodium phosphate to prepare the titanium hydroxide-hydroxyapatite coating.The hydrothermal time was12.0h?24.0h,and the hydrothermal temperatures were 90??110??130??150??170?and190?.The morphology and phase analysis of titanium alloy substrate surface coating after different hydrothermal time and hydrothermal temperature were conducted to study the influence of hydrothermal time and hydrothermal temperature on hydroxyapatite coating.To study the effect of the effect of the first hydrothermal generated calcium titanate coating on hydroxyapatite nanorods,the titanium alloy sheets generated after different hydrothermal times were reacted at specific hydrothermal temperature and different hydrothermal times,and these titanium alloy sheets were characterized.In the first hydrothermal process,with different amounts of barium hydroxide,the concentration of barium hydroxide in the solution was:the reaction at 0.1m M?0.2m M?0.3m M?0.4m M?0.5m M?4m M?0.04M hydrothermal temperature of 180?for 3.0h,and then annealed at450?for 2h,and at the hydrothermal temperature of 90?in the mixed solution of sodium hydroxide and sodium phosphate for 24h,The analytical characterization and ferroelectric analysis were performed.Titanium dioxide nanotube coating was successfully prepared on the base surface of titanium alloy by the anodized method.Titanium dioxide nanotubes were arranged neatly,independent of each other and of uniform diameter.The pipe diameter was mainly distributed between 45 and 65nm.The titanium dioxide-calcium titanate coating was successfully prepared through the first hydrothermal reaction.The distribution of calcium titanate particles was chaotic.The length of calcium titanate particles obtained from the reaction thermal time was 0.5?5.0h was mainly distributed at 100?500nm,and the width was mainly distributed at 50?300nm.And with the increase of hydrothermal time,the deposition of calcium titanate will be relatively increased,but the deposition of calcium titanate coating compared to titanium dioxide nanotube coating,the amount of calcium titanate generation is less.After the completion of hydroheat,there are still many titanium dioxide nanotubes on the titanium alloy surface.When the hydrothermal reaction is 3.0h,the generated calcium titanate coating is the most evenly covered on the surface of the titanium alloy,and the size distribution of calcium titanate particles is also the most uniform.On the XRD map,the characteristic peak of calcium titanate is also strong.The first hydrothermal reaction was selected for a best reaction time of 3.0h.At the hydrothermal temperature of 90?,rod-shaped hydroxyapatite can be generated at the hydrothermal temperature is 90?,the length of rod hydroxyapatite increases with the reaction time.The length of hydroxyapatite nanoroparticles generated with in 0?24h is mainly distributed between 500 and 1400nm,and the amount of hydroxyapatite generated also increases.Nanorods distribution is distributed,with hydroxyapatite nanorood length increasing with hydrothermal time.When the first hydrothermal time is long and the second hydrothermal time is relatively short,there will be a large number of calcium titanate particles generated by the first hydrothermal time on the surface of the titanium alloy.When the first hydrothermal time increases and the second hydrothermal time is long enough,the length of the hydroxyapatite nanorods increases.At the concentration of barium hydroxide is 0.1m M?0.2m M?0.3m M?0.4m M?0.5m M,the amount of barium titanate generated by the hydrothermal reaction is too small,and the ferroelectricity of the coating is not obvious.At the concentration of barium hydroxide is 4m M and 0.04M,the amount of barium titanate generated is increased,the coating has obvious ferroelectricity,and the ferroelectric residual polarization P_ris 0.031 and 0.0347?C/cm~2respectively.The higher the barium hydroxide concentration,the better the ferroelectricity of the reaction-generated coating.