摘要
为研究Si对简单NiAl涂层抗高温氧化性能的影响规律,改变料浆中Si/(Si+Al)比值(8%、17%和30%,质量分数),制备了3种不同Si含量的改性NiAl涂层。采用XRD、SEM、EPMA等表征方法分析了简单NiAl涂层和3种Si改性NiAl涂层氧化前后的相结构和显微组织。结果表明:4种铝化物涂层主要相均为δ-Ni_(2)Al_(3)和β-NiAl相。Si以CrSi_(2)、Cr_(5)Si_(3)和Ni_(2)Si硅化物的形式存在于涂层表层。在1000℃氧化500h后,简单NiAl涂层具有最大的氧化增重为1.93mg·cm^(-2),而Si/(Si+Al)比值为8%的Si改性NiAl涂层具有最小的氧化增重。在NiAl涂层中掺杂Si可促进α-Al_(2)O_(3)膜的形成,通过形成硅化物减少难熔金属元素向涂层表面扩散,改善氧化膜表面质量,降低氧化速率。但是掺杂过量的Si会降低涂层表层Al含量,使涂层在氧化后期出现β相不足的问题,无法维持表面Al的选择性氧化。因此,当料浆中Si/(Si+Al)为8%,涂层表面Si含量为9.6%时,具有最高的抗高温氧化性能。
Si-modified NiAl coating has been studied by researchers due to its good performance in high temperature corrosive environment,but the effect of Si content on the high temperature oxidation resistance of the aluminide coatings has been seldom studied.To figure out this issue,three modified NiAl coatings with different Si contents were prepared by varying the Si contents 8wt%,17wt%and 30 wt%in the slurry.Phase structures and microstructures of the simple NiAl coatings and three Si-modified NiAl coatings before and after oxidation were analyzed by XRD,SEM and EPMA,etc.The results show that theδ-Ni_(2)Al_(3)andβ-NiAl are the primary phases of the four aluminide coatings.Si mainly locates in the upper zone of the Si-modified NiAl coatings in the form of silicides as CrSi_(2),Cr_(5)Si_(3)and Ni_(2)Si.After oxidation at 1000℃for 500 h,the simple NiAl coating has the maximum mass gain of 1.93 mg/cm^(2),while the Si-modified NiAl coating with Si content of 8wt%has the smallest mass gain.The dopant of Si into NiAl coatings can promote the formation of protectiveα-Al_(2)O_(3)film,retard the outward diffusion of refractory metal elements and improve the surface quality of the oxide film,resulting in reduced oxidation rate.However,the addition of Si reduces the Al content on the surface layer of the coating and may make the coating insufficient ofβphase to maintain the selective oxidation of Al in the later period of long-time oxidation.Therefore,when the Si content is 8wt%,the Si-modified NiAl coating possesses the best oxidation resistance.
作者
马德政
范其香
王铁钢
张超
于昊君
Ma Dezheng;Fan Qixiang;Wang Tiegang;Zhang Chao;Yu Haojun(Tianjin Key Laboratory of High Speed Cutting and Precision Machining,Tianjin University of Technology and Education,Tianjin 300222,China;Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;No.703 Research Institute of CSSC,Harbin 150078,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2024年第2期509-519,共11页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51501130)
天津市教委科研计划(2022ZD033,2022ZD020)
天津市研究生创新基金(2021YJSS228)
天津市科技计划项目(22YDTPJC00450)
国家重点研发计划(2020YFB2010400)。
关键词
料浆法
AL-SI涂层
高温氧化
组织结构
slurry method
Al-Si coating
high temperature oxidation
structure
作者简介
马德政,男,1996年生,硕士,天津职业技术师范大学,天津300222,E-mail:1908187337@qq.com;Corresponding author:Fan Qixiang,Associate Professor,Tianjin Key Laboratory of High Speed Cutting and Precision Machining,Tianjin University of Technology and Education,Tianjin 300222,P.R.China,E-mail:qxfan@tute.edu.cn。
