反复熔铸镍铬合金在腐蚀液中的镍离子析出

背景:重复熔铸镍铬烤瓷合金是否会加大镍离子的析出,从而降低抗腐蚀性能,研究结论不一。目的:检测非真空状态下反复熔铸镍铬烤瓷合金在人工唾液中镍离子的析出量,分析熔铸次数对合金抗腐蚀性能的影响。方法:非真空状态下反复熔铸镍铬烤瓷合金Ⅰ、Ⅱ、Ⅲ、Ⅳ代,将试件浸泡于按照ISO标准制定的pH值为6.8,4.0的人工唾液中(168±1)h,恒温(37±1)℃,利用Z-5000原子吸收分光光度计检测不同pH值人工唾液中镍离子的析出量。结果与结论:相同pH值状态下,经两两比较发现,4代Ni-Cr烤瓷合金差异均有显著性意义(P<0.05),铸造第Ⅳ代镍离子析出最多,其次为Ⅲ代、Ⅱ代。随pH值的降低,合金的抗腐蚀性能降低,镍离子析出增多。提示非真空条件下反复熔铸镍铬烤瓷合金的耐腐蚀性能下降,随着熔铸次数的增加,镍离子的析出明显增多。

Ni ion precipitation from the repeated casted nickel-chrome alloy in corrosion

BACKGROUND: Whether repeated casted nickel-chrome alloy can increase the precipitation of nickel ions thereby to reduce the corrosion resistance is controversial. OBJECTIVE: To detect the nickel ion amount released from repeated casted nickel-chrome alloy in the artificial saliva in the non-vacuum state and to analyze the influence of cast times on the alloy corrosion resistance. METHODS: The nickel-chrome alloy was used to roast the porcelain alloy repeatedlyⅠ, Ⅱ, Ⅲ, Ⅳ generations. The specimens were immersed in the artificial saliva with pH of 6.8 and 4.0 for (168±1) hours at (37±1) ℃. Z-5000 atomic absorption spectrophotometer was used to determine the precipitation of nickel ions under different pH values. RESULTS AND CONCLUSION: Under the same pH value, nickel-chrome alloy Ⅳ was significantly different from other generations (P < 0.05), and had the largest amount of nickel ions, the secondary was Ⅲ, Ⅱ. With the decrease of pH value, the alloy had the decreased corrosion resistance with increased amount of nickel ions. The findings indicated that under non-vacuum condition, repeated casted nickel-chrome alloy has a decreased corrosion resistance and increased nickel ions with the increase of casting times.