提高单晶炉真空密闭性能的探讨

Investigation on the Improvement of the Vacuum and Obturation in Crystal Puller's Chamber

晶间腐蚀、应力腐蚀和缝隙腐蚀,是单晶炉炉室发生水渗漏的主要原因,因而是制造过程中材料选择、热加工工艺、机械设计与加工以及设备使用中要特别予以关注的问题。在至少380°以上温度进行热时效会强化材料的晶间敏化趋向,较合理的措施是进行振动时效处理。结构设计中还应对炉室工作时的热应力及其作用加以考虑,热场设计中应对炉室内壁材料的晶间敏化问题和单晶棒产生的热辐射予以重视。纯净的冷却水是防止或减少腐蚀的重要条件。

Intercrystalline corrosion, stress corrosion and gap corrosion play the key roles in the leakage of the crystal puller' s chamber. Therefore they are important during the chamber design to choose appropriate material, to take reasonable hot work technology, and to arrange logical machining processes and even to follow a reasonable using procedure. It is found that using a hot ageing temperature above 380℃ could increase the tendency of intercrystalline sensitization, however, it is also found a substitution measure could be vibratory stress relief to the chamber. It needs to mention that the thermal stress, thermal field and heat radiation from crystal stick on the chamber can not be ignored in the design of the chamber. Based on working experience, taking pure water as cooling media is a good choice to prevent/reduce corrosion of the chamber.