离心凝胶注模技术制备梯度ZrO2/HA复合材料

摘要

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223.5 mPa·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1 500 r/min的转数下离心10 min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1.76 MPa· 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 40wt％ solid content and 15wt％ ZrO2 is 223.5 mPa · s,showing good dispersion of slurries.When the catalyst content is 1.Swt％ and the initiator content is 0.6wt％,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 h have good gradient distribution of ZrO2 phase.The bending strength and fracture toughness of gradient ZrO2/HA composites with 15wt％ 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.