鎳基690合金之應力腐蝕破裂研究

Studies on the SCC of Nickel-Based 690 Alloy

本研究對於合金690在硫代硫酸鈉溶液中敏化的影響，及在含氯鹽環境下改變測試溫度、溶液濃度及pH值，以探討溫度、濃度及pH值對破裂的影響。希望研究結果可以提供製程溫度、濃度及pH值調整對材料可靠度影響的參考數據。研究顯示，在室溫下高濃度NaCl 5N溶液中，pH 3為一臨界值，低於此pH值時，應力腐蝕產生。同樣在NaCl pH 1溶液中，濃度1N亦為一臨界值，高於此濃度時，應力腐蝕問題產生。至於溫度對應力腐蝕的影響，在低pH 值中較能顯現出。

This study investigates the effect of sensitization of nickel-based 690 alloy in thiosulfates and the environmental effects on the stress corrosion cracking in chloride solutions. The results indicate that the solution pH value of 3 and 1 are the critical value for stress corrosion cracking in 5 N and 1N NaCl solutions, respectively. In chloride solutions with low pH value, the solution temperature promotes stress corrosion cracking.