不同Cr含量的Ni-Cr合金熔覆层的高温氧化和热腐蚀特性  

High-Temperature Oxidation and Hot Corrosion Characteristics of Ni-Cr Alloy Cladding Layers with Different Cr Contents

作　　者：陈珊珊[1] 刘宗德[1] 潘朝阳 刘福来 付云娣 Chen Shanshan;Liu Zongde;Pan Chaoyang;Liu Fulai;Fu Yundi(Key Laboratory of Power Station Energy Transfer Conversion and System,Ministry of Education,North China Electric Power University,Beijing 102206,China)

机构地区：[1]华北电力大学电站能量传递转化与系统教育部重点实验室,北京102206

出　　处：《稀有金属材料与工程》2023年第8期2702-2710,共9页Rare Metal Materials and Engineering

摘　　要：采用激光熔覆技术制备了Cr质量分数为10%、20%和40%的Ni-Cr合金熔覆层,研究了其在900℃下的高温氧化特性和600℃下Na_(2)SO_(4)+25%K_(2)SO_(4)混合盐中热腐蚀特性。结果表明,Cr含量对熔覆层的高温特性起着关键作用。提高Cr含量对提升熔覆层抗硫酸盐诱导的热腐蚀能力比提升抗循环高温氧化能力更有效。Cr40涂层抗高温氧化和热腐蚀性能最佳。Cr10的氧化产物以NiO为主,极易脱落,内部氧化严重。虽然Cr40表面可以形成单一的Cr_(2)O_(3)层,但热应力和生长应力引起的富Cr氧化物内部开裂,使Cr40的抗循环高温氧化能力仅略好于Cr20。面对热腐蚀时,Cr10表面呈现层状NiO和Ni_(3)S_(2)叠层分布的腐蚀产物,内部腐蚀区也生成了Ni的硫化物。Cr20表面Cr_(2)O_(3)层被破坏,内部腐蚀严重,生成了CrS。Cr40表面生成了致密的Cr_(2)O_(3)保护层,有效地防止了进一步腐蚀。Ni-Cr alloy cladding layers with Cr contents of 10wt%,20wt%,and 40wt%were prepared by laser melting technique and their high temperature oxidation characteristics at 900°C and hot corrosion characteristics in Na_(2)SO_(4)+25wt%K_(2)SO_(4)mixed salt at 600°C were investigated.The results show that the Cr content plays a key role in the high temperature characteristics of cladding layers.Increasing the Cr content is more effective in improving the resistance of cladding layers to sulfate-induced hot corrosion than in improving the resistance to cyclic high-temperature oxidation.Cr40 provides the best resistance to high-temperature oxidation and hot corrosion.The oxidation products of Cr10 are dominated by NiO,which is extremely easy to shed and the internal oxidation is serious.Although a single Cr_(2)O_(3)layer can be formed on the Cr40 surface,cracking within the Cr-rich oxides caused by thermal and growth stresses renders the resistance of Cr40 to cyclic high-temperature oxidation only slightly better than that of Cr20.Suffering from hot corrosion,the surface of Cr10 presents lamellar NiO and Ni_(3)S_(2) stacked distribution of corrosion products,and Ni sulfide is also generated in the inner corrosion zone.The Cr_(2)O_(3)layer on Cr20 surface is destroyed,and internal corrosion is severe,generating CrS.A dense protective Cr_(2)O_(3)layer is generated on Cr40 surface,efficiently preventing further corrosion.

关 键 词：NI-CR合金 激光熔覆技术 高温氧化 高温硫酸盐腐蚀 

分 类 号：TG174.4[金属学及工艺—金属表面处理] TG665[金属学及工艺—金属学]