CaCO_3溶液中黄铜和紫铜表面结垢特性

为研究CaCO3析晶污垢在黄铜和紫铜表面的生长特性,在35℃、0.5mmol/L的CaCO3溶液中,通过静态反应,采用称重法获得不同浸入时间的结垢质量,并采用扫描电子显微镜（SEM）得到不同浸入时间污垢的微观形貌.结果表明：相同条件下紫铜比黄铜更易结垢;pH升高不仅使结垢量增大而且促进四方形文石和方解石的形成,并且四方形文石逐步重结晶形成热力学最稳定晶型（方解石）;pH升高使本体溶液中均相成核率和金属表面异相成核率均增加,且均相成核率增加更多.

Deposition Behavior of Scales on Brass and Copper Surface in CaCO3 Solution

To study the deposition behavior of CaCO3 scales on brass and copper surface,experimental tests were carried out at static state in 0.5 mmol/L CaCO3 solution at 35 ℃,during which the scales obtained in different dipping durations were measured by weighing method and analyzed using scanning electron microscope.Results show that the scales are found to be more easily formed on copper surface than on brass surface under same conditions;higher pH value promotes not only the growth of scales,but also the formation of square aragonite and calcite,and the square aragonite will finally get recrystallized into the thermodynamically most stable phase（calcite）;with the rise of pH value,both the homogenous nucleation in solution and the heterogeneous nucleation on metal surface increase,and the former one increases more than the latter one.