Development of Corrosion resistant dental Ag-based alloys with low Pd and Cu content.

为研制一种低钯含量的高耐蚀牙科铸造合金，研究了25种实验用Ag-Pd-Cu-Au合金和5种Ag-In-Au合金在0.9%NaCl和0.1%Na_2S溶液中的腐蚀行为。通过电化学技术和原子吸收分光光度法分析释放的金属离子来评估耐腐蚀性。采用X射线光电子能谱（XPS）对合金表面进行了分析，发现Ag-Pd-Cu-Au合金在模拟口腔环境中保持足够的耐腐蚀性需要15%（质量分数）的Pd。Ag-15 Pd-15 Au-（10-20）Cu合金可以替代目前用于镶嵌、冠、桥的Ag-20 Pd-（10-20）Cu-12 Au合金，对于Ag-In-Au合金体系，少量的Au（1-3 mass%）显著提高了Ag-20 In合金在0.9%NaCl溶液和0.1%Na2S溶液中的耐蚀性。Ag-20 In-（1-3）Au合金可用作具有高耐蚀性的无钯牙科铸造合金。这些合金适用于嵌体和牙冠。

The corrosion behaviors of twenty five experimental Ag-Pd-Cu-Au alloys and five Ag-In-Au alloys were examined in 0.9% NaCl and 0.1% Na_2S solutions to develop a high corrosion resistant dental casting alloy with low Pd content. The corrosion resistance was evaluated by electrochemical techniques and the analysis of released metal ions by atomic absorption spectrophotometry. The surface of the alloy was analyzed by X-ray photoelectron spectroscopy (XPS).It was found that the 15 mass % of Pd was required for the Ag-Pd-Cu-Au alloys to maintain sufficient corrosion resistance in simulated oral environments. The Ag-15Pd-15Au-(10-20)Cu alloys can be alternatives to the Ag-20Pd-(10-20)Cu-12Au alloy that is currently used for inlays, crowns and bridges.For Ag-In-Au alloy system, small amount of Au (1-3 mass%) drastically improve corrosion resistance of the Ag-20In alloy both in 0.9% NaCl solution and 0.1% Na_2S solution. The Ag-20In-(1-3)Au alloy is can be used as a Pd-free dental casting alloy that possesses high corrosion resistance. These alloys are suitable for inlays and crowns.