作　　者： ; ; ; ;

机构地区： 东北大学材料与治金学院材料各向异性与织构工程教育部重点实验室

出　　处： 《东北大学学报（自然科学版）》 2013年第11期1580-1584,共5页

摘　　要： 采用涂盐法研究了DZ792与DZ792G合金涂覆75％Na2SO4＋25％NaCl混合盐后在900℃下的热腐蚀行为与机理．结果表明，900℃涂盐腐蚀条件下DZ792与DZ792G合金的热腐蚀机制为“酸／碱盐溶一内硫化氧化”．DZ792G合金在热腐蚀70～150h，腐蚀机制由碱性盐溶机制转化为酸性盐溶机制，最终导致灾难性腐蚀．DZ792G合金因具有较高的Ti含量，合金表面氧化膜的外侧形成富Ti氧化物层，TiO2与熔盐反应消耗其中的O。，促进热腐蚀由碱性向酸性盐溶机制转变．而DZ792合金Ti含量较低，TiO2层在氧化膜内侧形成，外侧少量Ti氧化物形成稳定的NiTiO3尖晶石层．DZ792合金氧化膜外侧的富Cr2O3层与熔盐直接反应，抑制了热腐蚀反应，因而具有优异的抗热腐蚀能力． The hot corrosion behaviors and mechanisms of DZ792 and DZ792G alloys at 900℃ through 75% Na：SO4 ＋ 25% NaC1 salt deposit were investigated. The results showed that the hot corrosion mechanisms of DZ792 and DZ792G alloys under 900 ℃ salt deposit were ＂acidic-alkali dissolution/inter sulfide-oxide＂. During the hot corrosion testing between 70 h and 150 h, the corrosion mechanism of DZ792G alloy changed from alkali to acidic dissolution mechanism, finally resulting in the catastrophic corrosion for DZ792G alloy, the 02- in molten salt preferentially reacted with the outside Ti-rich layer at the surface of DZ792 alloy rather than that with inner Cr203 layer owing to the high Ti content of this alloy, thus, the mechanism of the hot corrosion changed from alkali to acidic dissolution with the TiO2 reacted with the molten salt consuming the O2. However, because the Ti content of DZ792 alloy was lower than that of DZ792G, the Ti-rich layer formed in the middle of the multilayered oxide, and the outer Ti-rich oxide formed stable spinel NiTiO3. The outer Cr203 rich oxide layer of the DZ792 reacted with the salt directly, therefore, the further corrosion of DZ792 alloy enable to be inhibited.

关 键 词： 定向凝固镍基高温合金 盐膜 混合盐 热腐蚀行为

领　　域： [金属学及工艺] [一般工业技术] [金属学及工艺] [金属学及工艺] [金属学及工艺]