机械力化学法制备单相莫来石的机理研究

以高岭土和氢氧化铝为原料，采用机械力化学法制备出了单相莫来石。用热重-差示扫描分析研究了混合粉体经高能球磨后的结构变化，并讨论了单相莫来石的形成机理。结果表明：高能球磨破坏了混合物的晶体结构；随着粉磨的进行，混合物的比表面积会增加，无序程度也会增加，键能会减小，从而导致了内部贮能的增加，反应活化能的减小，并可得到均匀混合物。粉磨30h混合物制成的烧结体的热膨胀系数要比未粉磨的低约20％。

STUDY ON SYNTHETIC MECHANISM OF SINGLE PHASE MULLITE BY USING MECHANOCHEMICAL METHOD

Single phase mullite were prepared by using mechanochemical method with kaolinite and aluminum hydroxide as star-ting materials. The effect of grinding in a planetary ball mill on the structure of the mixtures was investigated by thermogravimetrydifferential scanning calorimetry (TGDSC). The formation mechanism of single phase mullite was discussed. Results show that the crystal structure of mixture is destroyed by high energy grinding. Along with the grinding time the specific surface area of the mixture increases and the bond energy reduces, resulted in the increase of the internal energy and decrease of the activation energy. Thus the uniform mixture was obtained. The thermal expansion coefficient of the sintered bodies after grinding for 30 h are about 20% lower than that of the unground mixture.