声电沉积钙磷生物涂层工艺中超声波的作用机理研究

Research on Action Mechanism of Ultrasonic to Calcium Phosphate Coatings on C/C Composite for Sonoelectrodeposition Technique

采用声电沉积工艺,在碳/碳复合材料表面制备了生物活性透钙磷石涂层工艺,借助SEM,EDAX,精密天平等分析手段,根据该涂层的沉积动力学规律,探讨了声电沉积工艺中,超声波在钙磷涂层形成中的作用机理。结果表明,在10～18mA/cm^2的范围内,随电流密度增加,透钙磷石涂层内晶粒仍呈片状,但尺寸逐渐减小,沉积速率依次增加;在沉积初期内,透钙磷石涂层沉积过程受扩散过程控制;声电沉积工艺中,超声波引入可导致界面附近扩散层内pH降低以及磷酸钙涂层沉积所需临界电荷密度降低,电流密度与诱导期之间符合Sand关系式。

Bioactive brushite coatings were prepared by sonoelectrodeposition technique on C/C composite. The action mechanism of ultrasonic wave on the formation of calcium phosphate coatings was explored on the basis of deposition kinetic of brushite coatings with aid of SEM, EDAX and Analysis Balance. The results showed that with increasing current densities in the range of 10-18 mA/cm^2, the size of sheet brushite coatings decreased whereas the deposition rate of it increased. At the initial stage, the deposition process of brushite coatings was controlled by ion diffusion, and the dependence of current density on induction time was in consistence with Sand expression and the introduction of ultrasonic to electrolyte could accelerate diffusion of OH- folmed on C/C surface and decrease pH value in the interface between the electrolyte and C/C cathode.