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研究铸态和预氧化态Ni-xCr-6.8Al基合金在Na2SO4+25%NaCl混合盐中873K时的热腐蚀行为。结果表明:NixCr6.8Al基合金的质量损失随着Cr元素含量的增加而减少,预氧化可以明显改善材料的抗热腐蚀性能,并且与Cr含量无关。Ni12Cr6.8Al基和Ni16Cr6.8Al基合金的热腐蚀动力学遵循抛物线规律,Ni-20Cr-6.8Al基合金遵循指数规律,所有的预氧化试样的热腐蚀动力学都符合对数规律。铸态合金热腐蚀的机理可以用酸碱熔融模型解释,而预氧化合金的热腐蚀机理在很大程度上由预氧化过程中形成的氧化层的性质决定。
The hot corrosion behavior of as-cast and pre-oxidized Ni-xCr-6.8Al-based alloys at 873K in Na2SO4 + 25% NaCl mixed salt was investigated. The results show that the mass loss of NixCr6.8Al-based alloy decreases with the increase of Cr content. Pre-oxidation can significantly improve the hot corrosion resistance of the material, and has nothing to do with the Cr content. The hot corrosion kinetics of Ni12Cr6.8Al and Ni16Cr6.8Al-based alloys follow the parabolic law. The Ni-20Cr-6.8Al-based alloy follows the exponential law and all the pre-oxidized samples have the same logarithmic law of hot corrosion kinetics. The mechanism of hot corrosion of as-cast alloys can be explained by the acid-base melting model, whereas the hot corrosion mechanism of the pre-oxidized alloys is largely determined by the nature of the oxide layer formed during the pre-oxidation.