发泡法-溶胶凝胶成型工艺制备莫来石晶须  

Preparation of mullite whiskers by foam-gel casting

作　　者：王龙庆[1] 冯涛 王刚[1] 董宾宾[1] 袁波[1] 张琪 Wang Longqing;Feng Tao;Wang Gang;Dong Binbin;Yuan Bo;Zhang Qi

机构地区：[1]中钢集团洛阳耐火材料研究院有限公司先进耐火材料国家重点实验室,河南洛阳471039

出　　处：《耐火材料》2018年第5期326-329,333,共5页Refractories

基　　金：国家自然科学基金重点项目(51272240)

摘　　要：为了获得长度较长、长径比大的莫来石晶须,以w(Al_2O_3)>98%、d_(50)=3μm的α-Al_2O_3微粉为铝源,w(SiO_2)>95%、d_(50)=2μm的熔融石英和工业级硅溶胶为硅源,工业级Al F_3·3H_2O为助剂,PAA为发泡剂,采用发泡法-溶胶凝胶成型工艺制备莫来石晶须,研究了Al F_3·3H_2O添加量(w)分别为2.5%、5%、7.5%、10%和15%以及热处理温度分别为1 200、1 300、1 400、1 500和1 600℃时对试样莫来石化及生成晶须形貌的影响,并用XRD、SEM对热处理后试样的物相组成及显微结构进行了分析。结果表明:1)制备莫来石晶须的最佳工艺条件是Al F_3·3H_2O添加量为7.5%(w),热处理条件为1 500℃保温6 h;2)生成的莫来石晶须长度可达360μm,直径3~9μm,长径比40~120;3)莫来石晶须的生长机制遵循气-固(VS)机制。In order to obtain long mullite whiskers with large length to diameter ratio, mullite whiskers were prepared by foam-gel casting using α-Al2O3 micropowder （w（Al2O3） 〉98% ,d50 =3 μm） as the aluminum source,fused quartz （w（SiO2） 〉95%, d 50 =2 μm） and industrial silica sol as the silicon source,industrial AlF3 · 3H2O as the promoter and PAA as the foaming agent. The effects of the AlF3 · 3H2O addition （2.5%,5%,7.5% ,10% and 15% ,by mass） and the hot treatment temperature （1 200,1 300,1 400,1 500 and 1 600℃） on mullitization and whisker morphology were investigated. The phase composition and microstructure of the specimens after hot treatment were analyzed by XRD and SEM. The results show that （1）the optimal technical condition is AlF3 · 3H2O addition of 7.5% and hot treatment at 1500 ℃ for 6 h; （2）the formed mullite whiskers have the length up to 360 μm , diameter of 3 -9 μm and length to diameter ratio of 40 -120;（3）the growth of mullite whiskers follows the vapor-solid mechanism.

关 键 词：莫来石晶须 氟化铝 气-固(VS)机制 发泡法 长径比 

分 类 号：TQ174[化学工程—陶瓷工业]