摘要
以硝酸铝和硅溶胶为原料,采用微沸法对合成纳米莫来石及其活化能进行研究,并用热重-差示扫描热量计(TGDSC)、X射线衍射仪(XRD)和扫描电子显微镜(SEM)对合成莫来石的粒度、相组成和形貌进行分析。结果表明:在原料中的铝硅摩尔比为3∶1的条件下,温度为854℃时莫来石开始形成,温度为920℃时Al-Si尖晶石开始转变为莫来石,温度为1200℃时莫来石化完成,合成莫来石的活化能为(634.52±28.90)kJ·mol-1。经过1200℃煅烧后,莫来石含Al2O3的摩尔分数为59.8%,平均粒度约为31.7nm,形状为针状,并由这些针状莫来石构成连续的网络结构。随着铝硅摩尔比的增加,合成莫来石的温度降低,活化能降低。当铝硅摩尔比增加至6∶1,合成莫来石的活化能降至(514.73±14.40)kJ·mol-1。
Nano-mullite was synthesized by micro-boiling method using aluminium nitrate and silica sol as raw materials,and the activation energy was studied.Grain size,phase composition and morphology of the mullite were analyzed by means of thermogravimetry-differential scanning calorimeter(TGDSC),X-ray diffraction (XRD) and scanning electron microscope (SEM),respectively.The results show that when Al/Si mole ratio is 3 ∶ 1 in the raw materials,mullite starts forming at 854℃,Al-Si spinel starts transforming into mullite at 920℃,mullitization is completed at 1200℃,and activation energy of mullite synthesis is (634.52±28.90) kJ · mol-1.After mullite is calcined at 1200℃,and the mole fraction of mullite containing Al2O3 is 59.8%,the average particle size is 31.7nm,with needle shape,and with these needle shape mullite forming a continuous network structure.The synthesizing temperature of mullite and activation energy decrease as mole ratio of Al/Si increases.Activation energy of synthesizing mullite decreases to (514.73 ± 14.40) kJ · mol-1 when mole ratio of Al/Si increases to 6 ∶ 1.
出处
《材料工程》
EI
CAS
CSCD
北大核心
2015年第6期26-30,共5页
Journal of Materials Engineering
关键词
微沸法
纳米莫来石
活化能
micro-boiling method
nano-mullite
activation energy