声电沉积C/C磷灰石生物活性涂层的超声作用机制

The Mechanism of Effect of Ultrasonic on the Apatite Bioactive Coating for C/C Composites by Sonoelectrodeposition

采用声电沉积工艺在炭/炭复合材料表面制备了磷灰石生物活性涂层,借助SEM,EDAX,XRD,FTIR等分析测试手段,考察了超声频率对涂层组成、结构和形貌的影响。结果表明:低超声频率时(25 kHz)形成片状羟基磷灰石(Ca_(10)(PO_4)_6(OH)_2(HA));当超声频率升高时(45 kHz或60 kHz)形成棒状磷酸氢钙(CaHPO_4·2H_2O(DCPD))。随着超声频率的升高,涂层呈紧密堆积并沿(021)、(041)晶面择优生长。涂层厚度和n(Ca)/n(P)逐渐减小,电解液的pH值逐渐升高。超声波对电沉积的作用主要是降低了钙磷相反应能垒和增强了类旋转效应。

To improve the osteo-integration ability of the surface of carbon/carbon composites, a bioactive apatite coating was prepared on carbon/carbon composites by a cathode sonoelectrodeposition technique. The effect of ultrasonic frequency on the morphology and phase composition of coating was investigated by SEM, EDAX, FTIR and XRD. The results show that, the plate-like crystals obtained at the ultrasonic frequency of 25 kHz are identified to be Ca10（PO4）6（OH）2（HA）, and the club-shaped precipitates formed at the ultrasonic frequencies of 45 kHz and 60 kHz are identified to be CaHPO4.2H2O（DCPD）. With increasing of ultrasonic frequency, the growth direction of the coating is preferentially along the crystal planes of （021） and （041）, and the thickness and n（Ca）/n（P） of the coating decrease continuously, while the pH value of the electrolyte increases. The contribution of ultrasonic to the electrodeposition is to decrease the energy barrier of the reaction between Ca^2＋ and PO4^3- and to improve the quasi-rotational effect.