中文摘要：

采用电化学工作站的开路电位和电化学阻抗谱法对牙科铸造镍铬合金在不同浓度表没食子儿茶素没食子酸酯（EGCG）人工唾液中的腐蚀行为进行了比较，并用扫描电镜观察比较了腐蚀后镍铬合金的表面形貌。结果表明，镍铬合金在不同浓度EGCG人工唾液中的开路电位大小顺序为1．0g／L〈4．0g／L〈0g／L，且在1.0g／L、4．0g／LEOCG人工唾液中其开路电位较快地达到了一个稳定值；同时，镍铬合金在不同浓度EGCG人工唾液中的等效电路极化电阻大小顺序为1．0g／L〈4．0g／L〈0g／L。扫描电镜显示镍铬合金在不同浓度EGCG中均有不同程度的腐蚀，表面出现点蚀，分布不均匀，孔径大小不一，其中以1．0g／LEGCG人工唾液中的腐蚀最明显，其次是4．0g／LEGCG。由此均说明镍铬合金在1．0g／LEGCG人工唾液中的耐腐蚀性能最差，各试件的耐腐蚀性能排序为1．0g／LEGCG〈4．0g／LEGCG＜0g／LEGCG。

英文摘要：

The corrosion resistance of NiCr dental casting alloys is evaluated by open circuit potential and electrochemical impedance spectroscopy measurements in artificial saliva with different concentrations of EGCG. The surface topography of NiCr alloys are also observed after electrochemical corrosion. The results show that the sequence of open circuit potential of NiCr alloys in artificial saliva with different concentrations of EGCG is 1.0g/L〈4. 0g/L〈 0g/L, and the open circuit potential of NiCr alloys in artificial saliva with 1.0g/L, 4. 0g/L EGCG quickly reached to a stable value. It is also found that the sequence of polarization resistance in equivalent circuit of NiCr alloys in artificial saliva with different concentrations of EGCG is 1.0g/L〈4. 0g/L〈0g/L. The results of scanning electron microscopy show that the pitting corrosion of different size appears in the surface of all NiCr alloys and the corrosion in the surface of NiCr alloy is most obvious after electrochemical corrosion in 1. 0g/L EGCG followed by 4. 0g/L EGCG. So the corrosion resistance of NiCr alloys in artificial saliva with different concentrations of EGCG is 1. 0g/L〈4. 0g/L〈 0g/L.