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研究了纯Ni、Ni-10Cr和Ni-10Cr-5Al合金在900℃空气中涂敷Na2SO4+25%NaCl盐膜时的热腐蚀行为。结果表明,Ni-10Cr合金的腐蚀动力学曲线近似服从抛物线规律,而纯Ni和Ni-10Cr-5Al合金的腐蚀动力学曲线分段服从抛物线规律。Ni-10Cr的腐蚀增重最小,抗热腐蚀性能最好,Ni-10Cr-5Al次之,纯Ni的腐蚀增重最大。Ni-10Cr-5Al合金热腐蚀24 h后氧化产物分为3层,外层氧化产物主要是NiO,中间层氧化产物为Cr2O3和Al2O3,最内层有少量Cr2S3和Al2S3。Ni-10Cr合金热腐蚀24 h后氧化膜分为3层,外层氧化产物是NiO,中间层是不连续的Cr2O3,内腐蚀区有少量Cr2S3。由于熔盐中NaCl的存在,Ni-10Cr-5Al和Ni-10Cr合金的腐蚀产物会变得疏松多孔。
The hot corrosion behavior of pure Ni, Ni-10Cr and Ni-10Cr-5Al alloy coated with Na2SO4 + 25% NaCl in air at 900 ℃ was studied. The results show that the corrosion kinetics curve of Ni-10Cr alloy obeys the parabolic law approximately, while the corrosion kinetic curve of pure Ni and Ni-10Cr-5Al alloy obeys the parabolic law. Ni-10Cr corrosion weight gain the smallest, hot corrosion resistance of the best, Ni-10Cr-5Al second, pure Ni corrosion weight gain the largest. After oxidation for 24 h, the oxidation products of Ni-10Cr-5Al alloy were divided into three layers, the main oxidation products of the outer layer were NiO, the middle layer oxidation products were Cr2O3 and Al2O3, and the innermost layer was a little Cr2S3 and Al2S3. The oxide film was divided into three layers after hot corrosion of Ni-10Cr alloy for 24 h, the outer oxidation product was NiO, the middle layer was discontinuous Cr2O3, and the inner corrosion area had a small amount of Cr2S3. Due to the presence of NaCl in the molten salt, corrosion products of the Ni-10Cr-5Al and Ni-10Cr alloys become loose and porous.