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应用X射线衍射(XRD)、扫描电子显微镜(能谱分析)(SEM-EDS)和电子探针显微分析等方法探讨了预涂覆碱金属硫酸盐的Co Cr Fe NiTi_(0.5)高熵合金在0.75%SO_2气氛中的腐蚀行为。结果表明:在0.75%SO_2气氛中,合金的腐蚀动力学曲线遵循“抛物线”规律;合金表面生成由Ti,Cr_2,Fe氧化物,尖晶石结构复杂氧化物AB_2O_4以及(Fe,Ni)硫化物组成的腐蚀产物;升高温度显著增加氧化膜厚度以及腐蚀影响区的孔隙密度,这使得氧化层与基体结合程度变差甚至剥离,腐蚀深度增大。Co Cr Fe Ni Ti_(0.5)高熵合金在含硫气氛下的腐蚀归因于腐蚀初期合金元素的氧化,以及随后发生的金属氧化物的硫酸盐化、三元共晶复合盐的形成以及合金元素Fe在熔盐中的溶解反应;不仅如此,介于合金基体与金属氧化层间的腐蚀影响区还发生了合金元素(Fe,Ni)的硫化。
The properties of Co Cr Fe NiTi_ (0.5) high entropy alloy precoated with alkali sulfate were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM- EDS) and electron probe microanalysis Corrosion behavior in 0.75% SO 2 atmosphere. The results show that the corrosion kinetics curve of the alloy follows the law of “parabola” in 0.75% SO 2 atmosphere. The surface of the alloy is composed of Ti, Cr 2, Fe oxides, spinel complex oxides AB_2O_4 and (Fe, Ni) Sulfide. The increase of temperature significantly increases the thickness of the oxide film and the pore density in the corrosion-affected zone, which leads to the deterioration of the adhesion between the oxide layer and the substrate and even the increase of the corrosion depth. Corrosion of the Co Cr Fe Ni Ti 0.5 (0.5) high-entropy alloy in a sulfur-containing atmosphere is attributed to the oxidation of the alloying elements at the initial stage of the corrosion followed by the sulfation of the metal oxides, the formation of ternary eutectic composite salts, and the alloys In addition, the elemental Fe dissolves in the molten salt. In addition, the alloying elements (Fe, Ni) are also vulcanized in the corrosion-affected zone between the alloy matrix and the metal oxide layer.