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低合金耐熱鋼T23在高溫超臨界CO2環(huán)境中的腐蝕特性研究

2021-05-10 15:50:31 作者：李瑞濤來源：中國腐蝕與防護學(xué)報分享至：

摘要

通過低合金耐熱鋼T23在650 ℃/25 MPa的高溫超臨界二氧化碳（s-CO2）下的1000 h氧化實驗獲得了T23鋼的氧化動力學(xué)特性，并借助SEM、XRD及EDS對氧化膜的形貌、物相和成分進行了分析。結(jié)果表明：T23鋼在650 ℃/25 MPa的高溫s-CO2中的氧化動力學(xué)符合立方規(guī)律，時間指數(shù)0.30。氧化膜具有典型的雙層結(jié)構(gòu)，外層氧化膜為Fe3O4且氧化膜疏松多孔，內(nèi)層氧化膜較為致密含有大量尖晶石結(jié)構(gòu)的Fe3-xCrxO4。T23材料在高溫超臨界CO2環(huán)境中形成的氧化膜較容易發(fā)生剝落，剝落腐蝕現(xiàn)象明顯。

關(guān)鍵詞： T23鋼 ; 高溫氧化 ; 高溫s-CO2 ; 剝落腐蝕

Abstract

The long term oxidation behavior of T23 steel, one of the low alloy heat resistant steels was examined in high-temperature supercritical CO2 at 650 ℃/25 MPa for 1000 h, so that, the oxidation kinetics of T23 steel was acquired. Meanwhile, the oxide scales formed on the steel were characterized by SEM, XRD and EDS. The results showed that the oxidation kinetics of T23 steel oxidized in high-temperature s-CO2 at 650 ℃/25 MPa followed the cubic law during the entire test duration. Meanwhile, the time index was also obtained by data analysis process and proved to be 0.30. The oxide scales formed on all the samples exposed for different time duration had a typical double-layered structure. Namely，the outer layer was porous and composed of Fe3O4. The inner layer composed of Fe3-xCrxO4 and was much denser than the outer layer. Also, the oxide scale formed on T23 steel in high-temperature s-CO2 was more likely to peel off and the exfoliation-like corrosion could be found obviously on the surface of the corroded steel.

Keywords： T23 steel ; high-temperature oxidation ; high-temperature s-CO2 ; exfoliated corrosion