快速冷冻干燥法制备多孔氧化硅陶瓷  

Preparation of Porous SiO_2 Ceramics by a Fast Cooling Freeze Casting Method

作　　者：刘晓光[1] 薛文东[1] 李妍[1] 石存兰[1] 李勇[1] 孙加林[1] 

机构地区：[1]北京科技大学材料科学与工程学院无机非金属材料系,北京100083

出　　处：《人工晶体学报》2016年第1期35-40,共6页Journal of Synthetic Crystals

基　　金：北京市自然科学基金(2154052);中国博士后基金(2014M560044);中央高校基本科研业务费专项资金(FRF-TP-15-006A2)

摘　　要：为制备氧化硅多孔陶瓷,尝试了快速冷冻干燥法,探索了氧化硅浆体的分散剂和pH值对孔结构的影响。结果表明:使用0.1wt%六偏磷酸钠作为分散剂时,孔壁处团聚现象明显;改用聚甲基丙烯酸钠团聚显著减少。主要原因是氧化硅表面的Si-OH可能与六偏磷酸钠络合成Si-Na_4P_6O_(18)^-,但其在水中易断裂,减弱了颗粒之间排斥力,未能抑制团聚;而聚甲基丙烯酸钠吸附在氧化硅表面,可能形成Si-C_4H_5O_2等空间位阻抑制团聚。在聚甲基丙烯酸钠的基础上再调节浆体pH值至~10使氧化硅的zeta电位达到^-60 mV,可更好抑制团聚。综上所述冻干法适合制备开口通孔结构的多孔氧化硅陶瓷。In order to prepare porous SiO_2 scaffolds,a fast cooling freeze casting(FCFC) method was explored and the influences of dispersants and pH values of SiO_2 slurries on the resultant pore structures were also investigated.The results show that dense agglomerations next to the resultant pore channels are observed when using 0.lwt%sodium-hexametaphosphate(SHMP).They can be effectively reduced when using 0.1wt%polymethacrylic Acid-Na Salt(Na[PMAA]).This may be ascribed to Si-OH on the SiO_2surface,which might be combined with SHMP to form Si-Na_4P_6O_(18)^-.However Si-Na_4P_6O_(18)^- normally breaks down to short chains,weakening the repellence forces between particles and being not good at agglomeration resistance.In contrast,Na[PMAA]may absorb onto SiO_2 surface and form Si-C_4H_5O_2 with strong steric hindrance,so it reduces agglomeration between SiO_2 particles.Based upon Na[PMAA],the agglomeration can be further avoided by adjusting the pH value of the SiO_2 suspension to ~ 10 with the zeta potential of SiO_2 reaches-60 mV.Overall,the freeze-casting technique is a proper one for porous SiO_2preparation with unidirectional open pore channels.

关 键 词：快速冷冻干燥法 氧化硅多孔陶瓷 团聚 分散剂 p H值 

分 类 号：TQ174.7[化学工程—陶瓷工业]