摘要
利用循环氧化法,研究了不同Si含量(0%,1%,3%,质量分数)的625合金熔覆层在700、800、900℃下氧化144 h后的高温氧化行为。用XRD分析了氧化物相。通过SEM/EDS研究了氧化物表面和截面的形貌、元素组成和氧化膜的厚度。结果表明,不同温度下试样的氧化动力学都保持抛物线规律,随着温度的升高,氧化增重逐渐增加。通过观察,在900℃时,0%Si含量的625合金熔覆层出现了氧化膜大面积剥落的情况,3%Si含量的合金熔覆层氧化膜保持完整。在700℃时,随着Si含量增加,氧化膜表面的氧化颗粒尺寸减小且更加致密,同时促进了Cr_(2)O_(3)氧化物的生成。在700℃下,0%Si含量的试样出现了大片的内氧化区域;1%Si含量的试样基体部分出现了2处条状的含Ni,Cr,Mo的氧化物相区;而3%Si含量的试样氧化后由于生成了富Si的内氧化层,这阻止了内氧化的发生。外层Cr_(2)O_(3)氧化膜和内层SiO_(2)的联合作用既阻止了O阴离子的渗入也抑制了Fe等金属离子的扩散,提高了合金熔覆层的抗氧化性。
The high temperature oxidation behavior of 625 alloy cladding layer with different Si contents was studied by cyclic oxidation method after 144 h oxidation at 700,800 and 900°C.The oxide phase was analyzed by XRD.The surface and cross section morphology,elemental composition and oxide film thickness were studied by SEM/EDS.The results show that the oxidation kinetics of the samples at different temperatures keep a parabolic law,and the oxidation mass gain increases gradually with the increase of temperature.The oxidation film of 0wt%Si 625 alloy cladding sample peels off in a large area at 900°C,while the oxidation film of 3wt%Si alloy cladding sample remains intact.With the increase of Si content at 700°C,the oxidation particles on the surface of the oxide film decrease in size and become denser,which promotes the formation of Cr_(2)O_(3).At 700°C,a large area of internal oxidation appears in 0wt%Si sample,there are two strip oxides containing Ni,Cr and Mo in the substrate of 1wt%Si sample,while the inner oxidation of 3wt%Si samples is prevented due to the formation of Si-rich inner oxidation layer.The combined effect of the outer layer of Cr_(2)O_(3) oxide film and the inner layer of SiO_(2) not only prevents the infiltration of O anions but also inhibits the diffusion of Fe and other metal ions,thus improving the oxidation resistance of the alloy cladding.
作者
张剑
刘宗德
马荷蓉
李悦
李家璇
Zhang Jian;Liu Zongde;Ma Herong;Li Yue;Li Jiaxuan(Key Laboratory of Power Station Energy Transfer Conversion and System,Ministry of Education,North China Electric Power University,Beijing 102206,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2022年第10期3602-3610,共9页
Rare Metal Materials and Engineering
基金
General Fund Project in Equipment pre Research Field(61409220202)。
关键词
激光熔覆
625合金
氧化动力学
氧化膜
扩散
laser cladding
625 alloy
oxidation kinetics
oxidation film
diffusion
作者简介
张剑,男,1997年生,硕士,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,电话:010-61772277,E-mail:120202202118@ncepu.edu.cn。
