氟化钠处理对炭/炭复合材料磷灰石生物活性涂层的影响

Effects of NaF treatment on the bioactive apatite coating for C/C composites

通过声电沉积工艺在炭/炭复合材料表面制备钙磷生物活性涂层,采用扫描电镜、X射线能谱仪、X射线衍射仪、红外光谱等方法研究了氟化钠处理前后钙磷生物活性涂层的形貌、结构和组成。实验结果表明:氟化钠能促进磷酸三钙转化为含氟羟基磷灰石(FHA),并提高涂层结晶度;经氟化钠处理后,羟基磷灰石(HA)的(112)、(300)衍射峰明显增强,涂层是HA和FHA的混合物。氟化钠处理前后涂层表面形貌均为片状晶体,但处理后其颗粒尺寸增大;氟化钠处理后涂层与基体的结合强度略有增强,结合强度可达4.08 MPa,涂层氟的含量为4.59 wt%。分析了炭/炭复合材料表面HA转变为FHA的反应机制。采用氟化处理HA制备FHA涂层时,应加入磷酸盐保持整个反应过程的pH值不变。

The bioactive apatite coatings were prepared on the surface of carbon/carbon composites using the method of sono-electrodeposition. The effects of NaF treatment on the morphology, structure and composition of the as-received coatings were investigated by SEM, EDAX, FTIR and XRD. The results show that NaF promotes the change of tricalcium phosphate to fluoridated hydroxyapatite together with increasing the crystallization degree of the coating. After being treated with NaF, the composition of the coating is a mixture of hydroxyapatite（HA） and F-rich apatite （FHA）. The coatings are both plate-like crystals before and after treatment, however, the size of the crystals increases after treatment. The bonding strength between the coating and C/C matrix increases slightly after being treated with NaF, the bonding strength can reach 4. 08 MPa, and the fluorine content of the coating was 4.59 wt%. In addition, the reaction mechanism of hydroxyapatite transformed to fluorine-containing hydroxyapatite was also discussed. To obtain fluorine-containing hydroxyapatite coatings with the treatment by NaF, it is necessary to introduce phosphate in the immersion solution in order to maintain the pH.