(西北工業(yè)大學凝固技術國家重點實驗室,西安710072; 2.西安理工大學材料科學與工程學院,西安710048)
摘 要: 在高真空下,研究了凈化劑B2O3, 79%SiO2+12.5% B2O3+2.2%Al2O3+0.6%CaO+5.7%Na2O(簡寫為Na-Ca-Al-B-Si)和50%Na-Ca-Al-B-Si+50%Na2B7O4對Cu50Ni50合金熔體在循環(huán)過熱過程中的過冷度及其穩(wěn)定性的影響。結果表明, B2O3的凈化過程為純物理凈化,合金熔體在循環(huán)過熱過程中不能獲得穩(wěn)定的深過冷; Na-Ca-Al-B-Si玻璃的凈化過程為物理-化學復合凈化,但由于該凈化劑粘度大,在循環(huán)過熱的冷卻過程中因發(fā)生合金熔體與凈化劑分離,使合金熔體表面氧化,導致合金熔體同樣不能獲得穩(wěn)定深過冷; 50%Na-Ca-Al-B-Si+50%Na2B7O4玻璃的凈化過程為物理-化學復合凈化,該凈化劑粘度適中,合金熔體在循環(huán)過熱過程中可以獲得穩(wěn)定深過冷。
關鍵字: 玻璃凈化劑; Cu-Ni合金;深過冷;物理凈化;化學凈化
（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
