原位合成莫来石柱状晶强化羟基磷灰石材料

Hydroxyapatite composites reinforced by in situ columnar mullite crystal

以羟基磷灰石（HA）为基体，经硅溶胶表面包覆处理的A12（S04）3（AES）为第二相，采用原位反应合成法制备自生莫来石柱状晶增强羟基磷灰石材料。研究莫来石晶体的形成过程以及复合材料的相组成、微观形貌和力学性能。结果表明，添加AES可以提高HA的抗弯强度，经1050℃烧结、含10％AES的复合材料抗弯强度可达71．21MPa，比基体提高185％；硅溶胶在加热过程中结晶化转变的顺序是：800℃以下为非晶态，800～950℃晶化成方石英，950～1100℃为方石英＋磷石英；A12（S04）3与Si02反应原位生成柱状莫来石，柱状莫来石可起到类纤维的增强作用使材料强度提高。

Hydroxyapatite（HA） composites reinforced by in situ formative columnal mullite crystal were prepared using HA as matrix and Al2（SO4）3 enwrapped with silica sol （AES） as a second phase. The growth of columnal mullite crystal, as well as the phase composition, microstructure and mechanical properties of composites were studied. The results show that the addition of AES can enhance the bending strength of the HA composites. When sintered at 1 050 ℃, the bending strength of the composites containing 10% AES is 71.21 MPa, increasing by 185% than that of the matrix. The order of the crystalline transition of silica sol in the heating process is as follows： amorphous below 800 ℃, crystobalite at 800- 950 ℃, cristobalite ＋ tridymite at 950-1 100 ℃. Columnar mullite crystal is generated by in situ reaction of Al2（SO4）3 and SiO2, which can play a role to enhance the strength of HA matrix like fibers.