本文所探討的主題包括410及316(Cu)不銹鋼的銹皮生成性質及其後續酸洗效果：在410不銹鋼的部份，主要針對熱處理氣氛及鹽浴處理對410 SS於退火時所生成的銹皮性質以及後續酸洗效果之影響進行研究。316(Cu)不銹鋼的部份則是著重於水蒸氣對316(Cu)不銹鋼在固溶化熱處理時的銹皮生成機制及後續酸洗效果之影響。

　　實驗結果顯示，經過熱輥軋後的410 SS，生長在材料表面的銹皮可輕易的經由硫酸酸洗加以去除。一旦經過退火處理，除銹的難易程度則取決於退火氣氛的種類：在潮濕空氣中所生成的銹皮最難去除；在乾燥空氣及氮氣中生成的銹皮次之；於還原性氣氛中生成的銹皮則是最容易被去除。410 SS在不同氣氛中所生成的銹皮在硫酸水溶液中的穩定性亦可經由量測材料在酸中的開路電位變化來判斷。當試片表面存在附著性較佳的銹皮時，開路電位會維持在較高的數值（約+ 450～+ 650 mVSCE之間），且隨著銹皮逐漸溶解或剝落，電位會逐漸下降。當銹皮完全被破壞時，酸液直接接觸金屬表面，此時電位會下降至接近金屬在酸液中之腐蝕電位（約- 450 mVSCE）。

　　經退火處理的410 SS銹皮結構主要由(Fe, Cr)3O4及Cr2O3所組成。經過鹽浴處理後，在試片表面僅發現Fe3O4存在。另外，由電化學試驗結果指出，利用量測開路電位是否衰退亦可用來預測酸洗終點；當開路電位衰退至不銹鋼的腐蝕電位時，即表示試片已被活化，材料表面之銹皮應已被清除，而清除銹皮所需之活化時間（）會隨著硫酸濃度及溫度的增加而減少。

　　由316(Cu) SS酸洗試驗結果顯示，熱處理氣氛中若存在水蒸氣時，會使得316(Cu) SS銹皮結構變得較為鬆散，因而有助於提升酸洗效率。利用TGA試驗可進一步瞭解316(Cu) SS在1030℃的乾燥空氣中進行熱處理時，試片表面僅生成一層相當薄的Cr2O3，一旦空氣中含0.1 atm 分壓之水蒸氣時，氧化速率會大幅增加，銹皮則變得較複雜且鬆散，呈現多層結構，此多層結構銹皮主要是氧化鉻與富鐵鎳之金屬相互交錯累積而成。

　The effect of heat treatment atmosphere on the scale formation and pickling performance of 410 and 316(Cu) stainless steels (SSs) was investigated.

　The experimental results indicate that the scale formed on 410 SS in the moist air was the most difficult to remove, while descaling was easy when the stainless steel was annealed in a reducing atmosphere (10% H2 + N2). The composition and microstructure of the oxides formed during annealing strongly affected the descaling performance.

　The scales formed on annealed 410 SS were composed mainly of (Cr, Fe)3O4 and Cr2O3. After molten salt treatment, only Fe3O4, was detected on top of the substrate. Potential decay was noticed during pickling in sulfuric acid, which was associated with the scale removing process. Furthermore, the activation time (τ) required to complete the descaling decreased with increasing concentration and temperature of sulfuric acid.

　Water vapor was detrimental to the pickling of 410 SS, while the presence of water vapor in the heat treatment atmosphere enhanced the descaling efficiency of 316(Cu) SS. From TGA results, the oxidation rate of 316(Cu) SS was accelerated in wet air as compared to that in dry air. In addition, a significant breakaway oxidation occurred, resulting in substantial weight gain, as the 316(Cu) SS was oxidized in moist air at temperatures above 950℃. The scaling behavior of 316(Cu) SS in wet air at 1030℃ could be divided into two stages based on the alteration of the oxidation rate. In each stage, the scale on 316(Cu) SS exhibited a different structure and morphology.

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