(西北工业大学凝固技术国家重点实验室,西安710072; 2.西安理工大学材料科学与工程学院,西安710048)
摘 要: 在高真空下,研究了净化剂B2O3, 79%SiO2+12.5% B2O3+2.2%Al2O3+0.6%CaO+5.7%Na2O(简写为Na-Ca-Al-B-Si)和50%Na-Ca-Al-B-Si+50%Na2B7O4对Cu50Ni50合金熔体在循环过热过程中的过冷度及其稳定性的影响。结果表明, B2O3的净化过程为纯物理净化,合金熔体在循环过热过程中不能获得稳定的深过冷; Na-Ca-Al-B-Si玻璃的净化过程为物理-化学复合净化,但由于该净化剂粘度大,在循环过热的冷却过程中因发生合金熔体与净化剂分离,使合金熔体表面氧化,导致合金熔体同样不能获得稳定深过冷; 50%Na-Ca-Al-B-Si+50%Na2B7O4玻璃的净化过程为物理-化学复合净化,该净化剂粘度适中,合金熔体在循环过热过程中可以获得稳定深过冷。
关键字: 玻璃净化剂; Cu-Ni合金;深过冷;物理净化;化学净化
（1. State Key Laboratory of Solidification Processing,
Northwestern Polytechnical University, Xi'an 710072, P.R.China;
2. College of Materials Science and Technology, Xi'an University of Technology, Xi'an 710048, P.R.China）
Abstract:The undercooling and its stability of Cu50Ni50 alloy melts were investigated in vacuo using different glass slags, B2O3, 79% SiO2+12.5B2O3+2.2 %Al2O3+0.6% CaO+5.7%Na2O(simplified as Na-Ca-Al-B-Si), and 50% Na-Ca-Al-B-Si+50%Na2B7O4. The results showed that different glass slag has different denucleating mechanism. The purification of B2O3 glass is only a physical process. The alloy melts can not obtain stable undercooling during superheating-cooling cycle. Taking 79%SiO2+12.5% B2O3+2.2%Al2O3+0.6% CaO+5.7%Na2O as purifying agent, the denucleating mechanism is a comprehensively physicochemical process. Yet the stability of undercooling is still low because of the separation between melt and glass occurred during cooling process of superheating-cooling cycle. Stable undercooling can be obtained by physicochemical denucleating processes of 50%Na-Ca-Al-B-Si+50%Na2B7O4 molten glass because of its appropriate viscosity.
Key words: glass denucleating agent; Cu-Ni alloy melts; high undercooling; physical purification; physicochemical purification
