ZSM-5单晶生长的研究

Studies on Single Crystal Growth of ZSM-5

本文研究了DEA(二乙醇胺)-Na_(2)O-SiO_(2)-Al_(2)O_(3)-H_(2)O体系中由晶种水热生长的ZSM-5单晶形貌和线性生长速度.晶体外部晶面为轴面(100)、(010)及坡面(101)、(011).在互相贯穿连生的各单晶之间,其对称轴互成倾角.

The morphology of ZSM-5 single crystals hydrothermally crystallized on seeds in a system of DEA(diethanolamine)-Na_(2)O-SiO_(2)-Al_(2)O_(3)-H_(2)O and growing rate of its faces were studied.The faces of single crystals were identified as pinacoid(100)(010)and dome(101)(011).Symmetry axes of single crystals formed penetration twins intersect each other with unnormal angles.It was found that there may be a induction period for growing and constant normal rate in wider range of crystallization.The activation energy of growth was calculated from the relation between growing rates and reaction temperature.The influence of reactant composition,the change of component in mother liquor and the chemical content in ZSM-5 unit cell were investigated.According to basic principles on crystal growth and ZSM-5 framework,a possible actual structure is proposed to estimate the density and layout of growing positions on different faces.The growth mechanism and the role of DEA is discussed upon face structure and growing units in mother liquor.The assumption that the units may be aluminosilicate polymeric anions is supported.