Ca2+的琼脂包覆及控释固化技术制备多孔Si3N4陶瓷  

Preparation of Porous Si3N4 Ceramics by Ca2+ Agar Coating and Controlled-release Curing Technology

作　　者：郭肖峰 马伊欣 魏正华 陈双 吴甲民[1] 林建平 GUO Xiaofeng;MA Yixin;WEI Zhenghua;CHEN Shuang;WU Jiamin;LIN Jianping(State Key Laboratory of Materials Processing and Die&Mould Technology,School of Material Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;Key Laboratory of Functional Materials and Applications of Fujian Province,School of Materials Science and Engineering,Xiamen University of Technology,Xiamen 361024,Fujian,China)

机构地区：[1]华中科技大学材料科学与工程学院,材料成形与模具技术国家重点实验室,武汉430074 [2]厦门理工学院材料科学与工程学院,福建省功能材料及应用重点实验室,福建厦门361024

出　　处：《硅酸盐学报》2019年第12期1801-1807,共7页Journal of The Chinese Ceramic Society

基　　金：福建省功能材料及应用重点实验室开放基金(fma201701);中央高校基本科研业务费专项资金(2018KFYYXJJ030)

摘　　要：基于高价反离子直接凝固注模成型工艺,采用乳化-固化法制备琼脂包覆Ca^2+的微球,利用琼脂在加热的浆料中溶解,缓慢释放出包覆的Ca^2+,Ca^2+压缩陶瓷颗粒间的双电层,实现Si3N4浆料的原位失稳固化。加入水相的5%(体积分数)、10%、15%和20%的Tween 80作为水相乳化剂,向油相中加入相同含量的Span 85作为油相乳化剂(水油体积比为1:1),讨论乳化剂加入量对琼脂包覆效果的影响。研究结果表明乳化剂加入量为10%时,制备出的琼脂微球尺寸分布均匀且球形度较好;采用琼脂包覆Ca^2+控释固化Si3N4浆料,可将固化时间缩短至1h;包覆Ca^2+的琼脂微球加入量为0.5%(质量分数)时,制备出的多孔Si3N4陶瓷固化性能和力学性能达到最优。经过1 800℃烧结2h,可获得显气孔率为60%,孔径分布为3.90μm,抗压强度为12.13MPa的多孔Si3N4陶瓷。采用琼脂作为高价反离子的包覆剂可以包覆各种高价反离子,从而有效改进现有方法,丰富固化剂的选择。The agar-coated Ca^2+ microspheres were prepared by an emulsification-solidification method based on high valence counter ions direct coagulation casting process.The agar can be dissolved in the heated slurry to release Ca^2+ ions slowly.Ca^2+ ions compress the double-layer between the particle surfaces to realize the in-situ solidification of the slurry.The effect of the emulsifier amount added on the agar coating performance was discussed.The results show that the prepared agar microspheres have a uniform size distribution and a good sphericity at the of emulsifier amount added of 10%.The curing time of Si3N4 slurry is shortened to 1h by using agar-coated Ca^2+ ions controlled releasing.The performance and mechanical properties of porous Si3N4 ceramics are optimized when the amount of agar-coated Ca^2+ microspheres of 0.5%(in mass fraction)is added.After sintering at 1 800℃ for 2h,porous Si3N4 ceramics with the porosity of 60%,average pore size of 3.90μm and compressive strength of 12.13 MPa can be obtained.Utilizing agar as a coating agent of high valence counter ions can coat various high valence counter ions,thereby effectively improving the existing methods and enriching the choice of curing agents.

关 键 词：直接凝固注模成型 多孔氮化硅陶瓷 琼脂包覆 高价反离子 可控释放 

分 类 号：TQ620.1[化学工程—精细化工]