利用激光熔覆的方法在纯钛表面制备了羟基磷灰石(HA)生物陶瓷梯度涂层,通过电子探针和X射线衍射仪(XRD)对不同工艺参数下制备的涂层进行了微观组织观察和物相分析。实验结果表明,当激光功率为600 W,扫描速度为3.5 mm/s时,在纯钛表面可获得组织致密结合形态好的HA生物陶瓷梯度涂层,涂层的组织为胞枝晶和枝状晶,与人体骨组织的结构相似,主要由生物活性较好的HA相以及α-Ca2P2O7,Ca3(PO4)2等钙磷相组成,涂层下部的Ca,P的原子比例与HA中的Ca,P的原子比例相当,涂层表面因P的丢失而使其比例略高。随着功率的提高,涂层组织出现了少量的微孔,微孔的出现有利于骨组织在其上面植入生长,但涂层中Ca,P的原子比例升高,涂层的生物活性降低。随着扫描速度的加快,涂层熔化不充分,组织疏松,强度降低,影响了其使用。

HA (hydroxyapatite) bioceramic gradient coatings are prepared on titanium by laser cladding, the microstructure and phases analysis of laser clad HA bioceramic coating are studied by means of electron probe microanalysis (EPMA) and X-ray diffraction (XRD). The results show that when the laser power is 600 W and the scanning speed is 3.5 mm/s, the compact and good-bonding HA bioceramic gradient coatings can be obtained, and the microstructure is cellular and dendritic crystal which is similar to that of human hard tissue. The coatings consist of the phases of HA, α-Ca2P2O7, Ca3(PO4)2 and so on, and the Ca/P ratio in bottom coating is near to that in HA, but in upper coating it is a little higher. If laser power rises, porous structure is produced which is favor to the embedding and growing of bone tissue, but the Ca/P ratio in HA coatings increases and the biocompatibility decreases. If the scanning speed is faster, the coating will not melt enough, so the microstructure is loose and the coating strength descends.