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Indexed by:会议论文

Date of Publication:2014-03-10

Included Journals:EI、CPCI-S、Scopus

Volume:541-542

Page Number:61-68

Key Words:multi-elements alloy; alkali metal sulfate; low melting point eutectic; basic fluxing

Abstract:Multi-elements alloy with good thermal stability is expected to serve as the superheater tube material of ultra-supercritical boiler and may suffer from hot corrosion under the coal-fired atmosphere. In this study, the corrosion resistance behavior of multi-elements alloy CoCrFeNiTi0.5 coated with alkali metal sulfates at 750 degrees C is investigated systematically. The results showed the corrosion kinetics curves of the alloy followed a "parabolic" growth rate. The corrosion products, which consisted of volatile Na (CrO4) (SO4), (Fe, Ni) xSy, Cr/Ti oxide as well as compound oxides with spinel structure AB2O4, were found in the oxide scale and internal attack zone of the alloy. The oxide layer had good adhesion with the matrix at the beginning of corrosion. Prolonging corrosion time, the oxide layer in thickness increased and became loose as well as porous. The micro-pores generated in the interface between the oxide scale and matrix with the occurrence of the internal oxidation and internal sulfidation. In a word, the corrosion resistance behavior of mult-ielements alloy CoCrFeNiTi0.5 at 750 degrees C can be attributed to the formation of the protective oxide layers and to the basic fluxing in molten Na4SO4 induced by low melting point eutectic.