离心凝胶注模技术制备梯度ZrO_2/HA复合材料

ZrO_2/HA composites prepared by centrifugal-gelcasting technology

采用离心-凝胶注模成型技术制备梯度ZrO2/HA复合材料,研究浆料固相含量、ZrO2含量对浆料粘度的影响。观察ZrO2/HA浆料的凝胶固化过程,分析离心成型工艺参数对ZrO2/HA生坯密度梯度的影响。观察烧结产物的显微组织并对复合材料的力学性能进行测试。结果表明,浆料固相含量为40%(质量分数),ZrO2含量为15%(质量分数)时,ZrO2/HA浆料粘度为223.5mPa·s,具有良好的分散性。当催化剂含量为1.5%(质量分数)和引发剂含量均为0.6%(质量分数)时,起始凝胶和终止固化时间与离心成型工艺相匹配。当在1 500r/min的转数下离心10min后,离心-凝胶注模成型所得生坯具有良好的密度梯度,经1 200℃烧结2h后试样顶部、中部和底部中ZrO2形成良好的梯度。当ZrO2含量为15%(质量分数)时,复合材料的抗弯强度和断裂韧性达到最大值84.2 MPa和1.76MPa·m1/2,比基体提高了159.8%和117.2%。

Centrifugal gelcasting technology was used to prepare gradient ZrO2/HA composites.The effects of solid contents and ZrO2 contents on slurries viscosity were studied.The gelcasting process of ZrO2/HA slurries was observed.The effects of centrifugal slip casting parameters on green density difference of ZrO2/HA samples were analyzed.The microstructure of the sintered products was observed and the mechanical properties of gradient ZrO2/HA composites were measured.The results show that the viscosity of ZrO2/HA slurries with 40 wt%solid content and 15 wt% ZrO2 is 223.5 mPa·s,showing good dispersion of slurries.When the catalyst content is 1.5 wt%and the initiator content is 0.6 wt%,the gelcasting process of ZrO2/HA slurries meets with centrifugal process.The green compacts centrifuged at 1 500 r/m form good gradient distribution of green density.SEM observation shows that the top,middle and bottom of the compacts sintered at 1 200℃ for 2 hhave good gradient distribution of ZrO2 phase.The bending strength and fracture toughness of gradient ZrO2/HA composites with 15 wt% ZrO2 come to the maximum of 84.2 MPa and 1.76 MPa·m1/2,which are 159.8% and 117.2% more than those of HA matrix.