电触头表面劣化的热力学分析

讨论了温度对熔池气体溶解度的影响；研究了触头表面裂化现象．结果表明：由熔池气体形成气泡的不同运动形式是触头表面形成各种劣化形貌特征的直接原因，而触头材料中杂的存在是熔池气体形成气泡的根本原因．因此，也是触头表面发生裂化的主要原因．此外，通过对热力学平衡常数物理意义的讨论表明：氧化物的分解温度不能作为银金属氧化物中金属氧化物热稳定性的判据，真正的判据是热力学平衡常数．

Thermodynamic analysis of contact surface deterioration

This paper discussed the influence of temperature on gas dissolubility and generation mechanism of air bubble in molten pool and analyzed the relationship between air bubble and electrode morphology. It was shown that the movement of air bubble in the molten pool caused the deterioration of contact surface. Different forms of motion of air bubble lead to forming different characteristics of morphology. Further study revealed that the air bubble was formed by the molten pool gas at the action of impurity existing in the contact material. Based on the result, a conclusion could be drawn that the impurity of contact material was the main reason of contact deterioration. The thermal equilibrium constant was discussed. The result indicates that the thermo-stability of AgMeO material depends on the thermal equilibrium constant rather than the decomposition temperature.