本文研究表面沉积2 mg/cm2氯化钠的2205双相不锈钢(2205 DSS)在500 vppm NaC(l g)流动气氛加热炉内550~850℃下之高温腐蚀.结果显示,2205 DSS之高温腐蚀动力学遵守)物线定律,腐蚀反应速率随温度的上升而加速.高温腐蚀后生成的腐蚀皮膜结构由外而内依次为Fe2O3、Fe3O4、Cr2O3及FeCr2O4,不同温度下腐蚀生成的皮膜结构并无明显相异,唯850℃之试片于氧化皮膜脱落后,从其表层较容易检测到S iO2及N iO.在双相结构腐蚀顺序实验中,对表面沉积2 mg/cm2氯化钠的试片,其腐蚀顺序与α、γ相无关,为全面性的腐蚀.但于500 vppm NaC l(g)的流动气氛下,虽无法分辨α、γ相的腐蚀顺序,但可发现γ相较α相有较快速腐蚀的现象.
The objective of this study was to figure out the hot corrosion behavior of 2205 duplex stainless steel(2205 DSS) within the temperature ranges from 550 to 850℃ in the static air condition with 2 mg/cm~(2)NaCl deposit,and in the air atmosphere condition with a constant flow rate of 500 vppm NaCl_((g)),respectively.Experimental results show that the hot corrosion kinetics met the parabolic rate law and the corrosion rate increased constantly with increasing temperature.The scales formed included Fe_(2)O_(3)/Fe_(3)O_(4)/Cr_(2)O_(3) and FeCr_(2)O_(4)from outer layer to inner layer.The sequence of formation is independent of the environment temperature,but the SiO_2 and NiO can be found in the substrate of 850℃specimen.The corrosion sequence in two phase structure of 2205 DSS was not influenced by α and γ phases in the 2 mg/cm~(2)NaCl deposit due to complete corrsion and in the air atmospheres condition with a constant flow rate of 500 vppm NaCl_((g)).In the case of constant flow rate of 500 vppm NaCl_((g)),the corrosion rate in the γ phase was greater than that in the α phase,although the corrosion sequence was not known.
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