沉淀包裹法制备纳米堇青石粉末  

FABRICATION OF α-CORDIERITE NANO-POWDER BY PRECIPITATION-COATING METHOD

作　　者：蔡舒[1] 徐明霞[1] 李金有[1] 刘建良[2] 郑福前[2] 

机构地区：[1]天津大学高温结构陶瓷及工程陶瓷加工技术教育部重点实验室,天津300072 [2]昆明贵金属研究所,昆明650221

出　　处：《硅酸盐学报》2002年第5期629-632,共4页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金资助项目 (5 0 0 72 0 14 )

摘　　要：以热喷雾法制得的镁铝氢氧化物 [MgAl2 .6 (OH) x]团簇粉末及MgCl2 ·6H2 O和水玻璃为原料 ,用沉淀法对MgAl2 .6 (OH) x 进行包裹 ,可获得无定形连续包裹层。在煅烧过程中包裹层和被包裹粒子发生一系列反应 ,生成无定形纳米镁铝氧化物 ,并均匀分散在基体中。镁铝氧化物可促进基体中无定形SiO2 向方石英的转化。在 85 0℃左右 ,纳米类尖晶石相与方石英同时从无定形基质中析出成核 ,随煅烧温度进一步升高 ,类尖晶石与方石英反应生成中间相假蓝宝石 ,随后在 12 5 0℃与基体中的无定形SiO2 反应生成α -堇青石。在 12 5 0℃煅烧合成的α -堇青石粉末粒子呈多角形态 ,平均粒径约为 2 0nm。Cordierite precursor with an amorphous coating layer were prepared by precipitation-coating method from agglomeration MgAl 2.6 (OH) x which was prepared by thermal spray method (from melting metal Mg, Al and distilled water), MgCl 2·6H 2O and sodium silicate. In the processing of sintering, reactions occurr between the coating layer and the coated powder to form an amorphous compound of MgO and Al 2O 3, which is evenly distributed in the amorphous matrix of SiO 2 and can speed up the crystallization of the amorphous SiO 2 to cristobalite. Calcined at 850 ℃, the nano_cristobalite is crystallized and spinel_like phase appears by the reaction between amorphous MgO and Al 2O 3. Further increasing the temperature, an intermediate phase (sapphirine) is formed which is resulted from the reaction between cristobalite and spinel_like phase, and then reacts with the amorphous silicate contained in this matrix at around 1 250 ℃ to form α _cordierite. The average size of α _cordierite powders crystallized at 1 250 ℃ is about 20 nm.

关 键 词：沉淀包裹法 制备 纳米堇青石粉末 类尖晶石 

分 类 号：TQ170.7[化学工程—硅酸盐工业] TB383[一般工业技术—材料科学与工程]