论文部分内容阅读
研究了Sr(NO3 ) 2 浸渍改性对γ Al2 O3 的高温热稳定作用 ,考察了Sr含量 (SrO/Al2 O3 摩尔比为 0 0 0 5～0 15 )以及热处理温度 (6 0 0～ 115 0℃ )和气氛等影响因素 .BET比表面积和粉末X射线衍射结果表明 ,高温下Sr物种的引入明显地抑制了氧化铝比表面积的损失和α相变 ,而水蒸气的存在则削弱了Sr物种的高温稳定作用 .随着Sr含量的增大 ,Sr物种的高温稳定作用增强 ,但过度提高Sr含量时 (SrO/Al2 O3 比为 0 15 ) ,Sr物种的纯机械混合掺杂的负作用超过其对Al2 O3 的稳定作用 .焙烧温度从 6 0 0℃升至 115 0℃ ,氧化铝与Sr物种固相反应的产物由二铝酸盐转化至六铝酸盐 .高温动力学研究结果表明 ,Sr的高温稳定作用主要是抑制焙烧过程中最初 1h内的烧结和其后α相变引起的比表面积损失
The effect of Sr (NO3) 2 impregnation on the high temperature thermal stability of γ Al2 O3 was studied. The effects of Sr content (SrO / Al 2 O 3 molar ratio 0 0 0 5 ~ 0 15) and heat treatment temperature (600 ~ 115 0 ℃) and atmosphere.The results of BET specific surface area and powder X-ray diffraction show that the introduction of Sr species at high temperature significantly inhibits the loss of specific surface area of alumina and the α phase transformation while the presence of water vapor weakens Sr species , And the stability of high temperature stability of Sr species was enhanced with the increase of Sr content. However, when the content of Sr was increased excessively (SrO / Al 2 O 3 ratio was 0 15), the negative effect of pure mechanical mixing of Sr species was more than Which can stabilize Al 2 O 3. The calcination temperature rose from 600 ℃ to 115 0 ℃, and the products of the solid phase reaction between alumina and Sr were converted from aluminate to hexaaluminate.The results of high temperature kinetics showed that the solid- The high temperature stability of Sr is mainly to suppress the loss of specific surface area caused by the sintering in the first 1 h during roasting and the subsequent α phase transformation