水热合成制度对水化硅酸钙孔结构的影响

研究了不同水热合成制度(钙硅摩尔比、水固比、合成温度和恒温时间)对合成水化硅酸钙孔结构的影响。运用SEM,氮吸附-脱附法和FHH模型分析了样品的微观结构,形貌,孔结构参数及表面分形特征。结果表明:随着钙硅摩尔比的增加,水化硅酸钙(CSH)的比表面积和累积孔体积先减小后增大,当钙硅比为0.5时达到最大值,但其平均孔径逐渐降低。随着水固比的提高,合成温度的升高和恒温时间的延长,水化硅酸钙的平均孔径变化有所不同。

Influence of Hydrothermal Synthesis Conditions on Pore Structure of Calcium Silicate Hydrates

To study the influence of different hydrothermal synthesis condition (calcium silicon mole ratio, water solid ratio, synthesis temperature and constant temperature time) on the pore structure of calcium silicate hydrates (CSH). The microstructure and morphology of samples were characterized by SEM, and the pore structure parameters of samples were determined by nitrogen adsorption–desorption method. FHH model were used to analyze the surface fractal characteristics of samples. Results show that with the increase of calcium silicon mole ratio, the specific surface area and cumulative pore volume of calcium silicate hydrates decrease first then increase, and reaching maximum when the calcium silicon mole ratio was 0.5. But the average pore diameter reduced gradually. With the raised of water solid ratio and increase of synthesis temperature and extension of constant temperature time, the average pore size have different changing trends.