【摘要】 在对金属凝固和过冷微观机理分析的基础上，分析了影响过冷的主要因素，计算了过冷时晶核的临界尺寸。专门制作了两个具有不同过冷度的锡凝固点密封容器，着重进行了不同粒度石墨粉的添加对锡凝固点的影响实验。在对比分析实验结果的基础上，提出了“小过冷锡凝固点”概念，对国际上“锡凝固点过冷必须大于４Ｋ才能获得理想的温坪”的观点提出了不同见解，并用实验结果证明了“小过冷锡凝固点”的可行性。更多还原

【Abstract】 The main factors effecting supercooling were analyzed and the crystalline grain critical size under supercooling has been calculated theoretically on the basis of the microcosmic mechanism analysis of pure tin freezing and supercooling. Two cells for freezing point of tin with different supercooling were developed. The experiments of influence of adding graphite powder with different sizes into the cells were engaged in. The concept of a “low supercooling freezing point of tin” was put forward on the basis of contrast and analysis of the results of experiments. This concept is different from the one generally held internationally that “an ideal freezing curve cannot be obtained until the supercooling of the freezing point of tin is deeper than 4K”. The results of these experiments indicated that reducing the supercooling of the freezing point of tin was feasible.更多还原