KINETICS OF CRISTOBALITE FORMATION FROM SILICIC ACID
KINETICS OF CRISTOBALITE FORMATION FROM SILICIC ACID
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DOI：
10.1111/j.1151-2916.1958.tb12890.x
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发表时间：
1958-01-01
影响因子：
3.9
通讯作者：
VERDUCH, AG
中科院分区：
文献类型：
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作者：
VERDUCH, AG
在945°~ 1085°C的温度范围内，对硅酸向方石英转变的速率实验表明，存在一个可测量的成核期。根据其随温度的变化，计算出成核过程的活化能为每摩尔102.8千卡。转化的第二步，包括新相的生长和完善，已被证明以每摩尔50.9千卡的活化能发生。从速率曲线的形状可以计算出，在本实验所涵盖的温度范围内加热硅酸的最终产物可能是具有相当明确的三层和两层结构单元交替序列节律的上层结构。研究还表明，方石英晶体从核心到表面的无序程度增加。
Rate experiments made on the transformation of silicic acid into cristobalite, in the temperature range 945° to 1085° C, have demonstrated the existence of a measurable nucleation period. From its variation with temperature, a value of 102.8 kcal. per mole has been calculated for the activation energy of the nucleation process. A second step of the transformation, involving the growth and perfecting of the new phase, has been shown to occur with an activation energy of 50.9 kcal. per mole. From the shape of the rate curves it has been calculated that a superstructure having fairly well‐defined sequence rhythms of alternating three‐ and two‐layer structural units might be the end product of heating silicic acid in the temperature range covered by the present experiments. It also has been demonstrated that the degree of disorder increases from the core to the surface of the transforming cristobalite crystals.