摘要
利用热重分析法、XRD和SEM (EDS)对比研究了700℃超超临界发电机组用K317和K325铸造合金在900和1000℃大气环境下氧化行为。结果表明,K317的氧化性能要优于K325。在900℃氧化时,2种合金的氧化增重遵循抛物线规律,而在1000℃氧化时,氧化增重均分段遵循抛物线规律。K317的氧化膜分3层,外层是NiO、TiO_2和NiCr_2O_4,中间层是致密的Cr_2O_3,内层是内氧化产物Al_2O_3。而K325的氧化膜分2层,外层是NiO, NiCr_2O_4和Nb_2O_5,内层是致密的Cr_2O_3和嵌入的Nb_2O_5颗粒,没有内氧化现象发生。在1000℃氧化时,K325中的Mo严重被氧化形成挥发性MoO_3;同时氧化膜发生了局部剥落现象,氧化膜的附着性相对较差。
High temperature oxidation behaviors of cast K317 and K325 alloy at 900 and 1000°C in air environment were contrastively investigated by TGA,XRD and SEM(EDS).The results show that K317 alloy has a superior oxidation resistance compared with K325alloy.The kinetic curves of the two alloys oxidized at 900°C for 100 h obey the parabolic rate law while those at 1000°C obey sectionally the parabolic rate law.The oxide structure of K317,from the top surface down to the base material,consists of NiO-TiO2-NiCr2O4composite oxide,Cr2O3 oxide dense band and Al2O3 internal oxide.In comparison,internal oxidation is not observed in K325 alloy whose oxide layer is composed of two oxide layers:NiO-NiCr2O4-Nb2O5 composite oxide and Cr2O3 oxide layer.Serious MoO3 volatilization and oxide spallation take place in K325 alloy after the oxidation at 1000°C for 100 h.In addition,the adhesion property of K325 alloy is worse than that of K317 alloy due to the occurrence of the micro-voids on the oxide layer/substrate interface.
作者
高双
侯介山
杨飞
王常帅
周兰章
Gao Shuang;Hou Jieshan;Yang Fei;Wang Changshuai;Zhou Lanzhang(Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2019年第3期960-966,共7页
Rare Metal Materials and Engineering
基金
国家能源局项目(NY20150102)
国家自然科学基金(51571191)
关键词
镍基高温合金
抗氧化元素
氧化动力学
氧化机理
Ni-based
superalloy, anti-oxidation
element
oxidation
kinetics, oxidation
mechanism
