本研究是探討經熱處理後之2205雙相不錯鋼，σ相析出對晶界腐蝕的影響。研究結果發現:泣的雙相不錯鋼經熱處理後，σ相在叫γ及叫α晶界析出;當溫度及時間增加時，α相中亦會析出σ相。σ相在叫γ晶界析出時，其界面附近之α相中有明顯的鋁缺乏現象。有關2205雙相不錯鋼對晶界腐蝕的敏感性，可以ASTMA262 Practice A草酸電解試驗法作定性評估; 而雙環電化學動電位再活化試驗法則可以進行定量分析。經熱處理之2205雙相不錯鋼，在鈞。c、pH=3、濃度1M之NaCI水溶液中進行極化曲線測試時，其孔蝕起始電位及孔蝕保護電位，隨σ相析出量的增加而下降。

In this study， effect of σphase precipitates on the inter granular corrosion and pitting corrosion of 02205 duplex stainless steels after heat treatment were investigated. It'sfound that precipitation of σphase were found along the alyand aIαgrainboundaries after heat treatment;σphase precipitates were found in αphase when time and temperature were high enough. Chromium depletion on the aside of the alyinterface was more pronounced than that on the y side. ASTM A262 Practice A oxalic acid etch test and double loop electrochemical potentiokinetic reactivation (DL-EPR) were used to evaluate the degree of intergranular corrosion in qualitative and quantitative manners， respectively. Cyclic potentiodynamic polarization measurements， in 1M NaCl solution of pH=3 at 25°C， revealed that Enp and Epp of 2205 duplex stainless steel decreased ifσphase precipitation occurred as compared with those of the solution annealed specimens and intergranular corrosion was observed after electrochemical testing.