摘要
采用Al2(SO4)3·18H2O和SiO2作为反应原料,在Na2SO4熔盐中合成了莫来石晶须,利用XRD、FESEM和SEM等手段研究了合成产物的组成和形貌,并研究了合成温度(700℃、800℃、900℃、950℃、1000℃、1100℃和1200℃)、熔盐用量(反应料与Na2SO4的质量比分别为2:1、1:1、1:2和1:4)、保温时间(2h、3h和4h)等工艺因素对合成反应的影响。结果表明:用熔盐法合成的莫来石不含其他晶相,纯度高,晶须直径在50~150nm,长度为3~8μm。研究还发现:Na2SO4熔盐的合适用量为反应料与Na2SO4的质量比是1:1,此时,混合料在900℃开始生成莫来石,950℃石英相基本消失,1000℃保温3h合成反应基本完成,超过1100℃时,合成的莫来石开始分解。因此,熔盐法合成莫来石的合理温度为1000℃保温3h。
The mullite whisker was prepared through reaction of aluminum sulphate and silica in molten sodium sulphate media. The phase composition and microstructure of the mullite whisker were analyzed by XRD, FESEM and SEM. Parameters affecting the synthesizing reaction were also studied,which include the reaction temperature(700 ℃,800 ℃,900 ℃,950 ℃, 1000 ℃, 1100 ℃ and 1200 ℃), salt addition( the mass ratio of reactant and Na2SO4 :2/1,1/1,1/2 and 1/4) and soaking time (2 h,3 h and 4 h). Results show that high purity mullite can be synthesized by this method with mullite whiskers 50 - 150 nm in diameter and 3 - 8 μm in length. The appropriate mass ratio of reactant and Na2SO4 is found to be 1/1 ,at which the mullite begins to generate at 900 ℃,the quartz phase will disappear over 950 ℃ and the full reaction will be completed after soaking for 3 h at 1000 ℃. When the temperature exceeds 1100 ℃,the generated mullite begins to decompose. Therefore,the reasonable synthesizing condition is at about 1000 ℃ for 3 h.
出处
《耐火材料》
EI
CAS
北大核心
2006年第3期165-168,共4页
Refractories
基金
国家自然科学基金项目(50472101)。
关键词
熔盐法
硫酸钠
莫来石
晶须
Molten salt, Sodium sulphate, Mullite ,Whisker