Inconel 740H合金在模拟煤灰/烟气中的抗腐蚀性研究

针对用于超超临界锅炉过热器管的镍基高温合金Inconel 740H,在750 ℃及合成烟气的条件下,研究了涂刷合成煤灰试样和无涂刷试样累计3000 h的腐蚀情况。利用XRD、EDS和SEM对试样的表面和截面进行了分析。结果表明,涂刷合成煤灰试样的腐蚀分为两个阶段,开始在表面生成Cr₂O₃保护膜,随时间的延长氧化膜被硫酸盐溶解,腐蚀程度较重。无涂刷试样的腐蚀为一个阶段,即氧化和硫化腐蚀。

Corrosion Resistance of Inconel 740H in Simulated Coal-ash/Flue-gas Environments

The corrosion behavior of Ni-based superalloy Inconel 740, as superheater tubing, was studied in environments of synthetic coal-ash/flue-gas and synthetic flue-gas at 750 ℃ for 3000 h comparatively. The corrosion product, the surface morphology and the cross-sectional morphology of the corroded alloy were characterized by means of SEM, EDX and XRD, respectively. The results indicate that the corrosion process of the alloy exposed to the synthetic coal-ash/flue-gas can be divided into two stages. During the initial stage, the Cr₂O₃ film formed and then the degradation of corrosion resistance of the alloy can be attributed to the dissolution of protective Cr₂O₃ film in sulphate. The corrosion mechanism of the alloy in the synthetic flue-gas without coal-ash is oxidation and sulfidation during the exposure.