水热电沉积羟基磷灰石涂层的研究

在0.0105mol/LCa(NO₃)₂,0.0063mol/LNH₄H₂PO₄,0.1mol/LNaNO₃,pH=4.6的电解液中,控制温度60～200℃,恒电流0.4mA/cm²,通过水热电沉积法制备羟基磷灰石涂层.实验结果表明,涂层晶体端面呈六边形棒状结构,涂层组分为缺钙磷灰石Ca_10-x(HPO₄)_x(PO₄)_6-x(OH)_2-x.经800℃烧结后涂层分解为HA和β-TCP的混合物.随温度升高,涂层n(Ca)/n(P)不断增大,涂层组分逐渐接近计量比的HA.涂层质量和结合强度随温度升高先增后减,在160℃时达到最大值16.7MPa

Studies on Hydrothermal Electrodeposition of Hydroxyapatite Coatings

Hydroxyapatite coatings were formed on titanium electrode by using the hydrothermal electrodeposition method in an autoclave. The electrolyte contained 0.010 5 mol/L Ca(NO3)2, 0.006 3 mol/L NH4H2PO4 and 0.1 mol/L NaNO3. The electrolyte temperature was controlled at 60—200 ℃ and pH value was adjusted at 4.6. After loading of a constant current at 0.4 mA/cm2 for 2 h, the deposits were characterized by XRD, FTIR, environment scanning electron microscopy and energy dispersive X-ray spectroscopy. The experiment results show that the deposit crystals are rods in shape, the edge face of rod is a defined flat hexagon and the width and length of the crystal rods increases continuously with increasing the electrolyte temperature. The component of coatings is calcium-deficient hydroxyapatite Ca10-x(HPO4)x(PO4)6-x(OH)2-x, 0≤x≤1], which decomposed into the mixture of hydroxyapatite and β-calcium phosphate after sintering at 800 ℃. The n(Ca)/n(P) ratio of the coatings increased and was close at 1.67 with the electrolyte temperature increasing. These results suggest that the component of coating is continuously close to stoichiometric hydroxyapatite with the electrolyte temperature increasing. Furthermore, mass gain of the coatings and bonding strength of coatings increase with electrolyte temperature increasing up to 160 ℃. The bonding strength of coatings after sintering at 800 ℃ for 6 h attained 16.7 MPa when the electrolyte temperature was controlled at 160 ℃.