自蔓燃高温合成Al_2O_3/B_4C复相陶瓷中硼酸铝相的消除  

Elimination of Aluminum Borate in SHS of Al_2O_3/B_4C Composite

作　　者：刘永合[1] 殷声[1] 魏延平[1] 赖和怡[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083

出　　处：《北京科技大学学报》1998年第4期344-348,共5页Journal of University of Science and Technology Beijing

基　　金：国家"863"资助项目(863-715-21-03)

摘　　要：研究自蔓燃高温合成 Al_2O_3/B_4C 中硼酸铝相的形成机制,提出硼酸铝相的消除途径.通过对各种条件下燃烧合成产物的 X 射线分析和 SEM 观察发现,在点火前保持低温易生成低温硼酸铝相 Al_4B_2O_9.自蔓燃方式合成过程中未反应的 B_2O_3是产生高温硼酸铝相 Al_(18)B_4O_(33)的主要原因,其形成量与初始反应物中 B_2O_3过量密切相关,并受 B_2O_3尺寸的影响.起始反应物的充分混合可以提高铝热反应程度,降低体系内未反应的 B_2O_3的量,可抑制硼酸铝的生成.The formation mechanism of aluminum borate in the combustion synthesis of Al_2O_3/B_4C composite was proposed.Based on the formation mechanism several approaches taken to eliminate them are discussed.The X-ray analysis and SEM observation of the SHS products at various conditions reveal that the holding at elevated temperature before ignition is conducive to the formation of Al_4B_2O_9.The unconverted B_2O_3 is the major cause of the formation of Al_(18)B_4O_(33)if the reaction proceeds in the SHS mode.The amount of Al_(18)B_4O_(33)formed is very sensitive to the excess B_2O_3 to the stoi-chiometry 4Al+2B_2O_3+C and influenced by the size of B_2O_3 powder.The high dispersion of the reactants is helpful in prompting the thermite reaction to consume B_2O_3 and hence inhibiting the aluminum borate formation.

关 键 词：硼酸铝 自蔓燃高温合成 复相陶瓷 

分 类 号：TQ174.758[化学工程—陶瓷工业]