放电等离子烧结Y掺杂Mo-Si-B涂层的高温抗氧化性能  

High Temperature Oxidation Resistance of Y-doped Mo-Si-B Coating by Spark Plasma Sintering

作　　者：靳鸣 邵蔚 贺定勇[1] 陈广辉[1] 谈震 郭星晔 周正[1] JIN Ming;SHAO Wei;HE Dingyong;CHEN Guanghui;TAN Zhen;GUO Xingye;ZHOU Zheng(Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学材料与制造学部,北京100124

出　　处：《中国表面工程》2024年第4期134-141,共8页China Surface Engineering

基　　金：北京市教委科技计划一般项目(KM202110005007);国家自然科学基金(25001014);高能束流加工技术重点实验室稳定支持项目。

摘　　要：稀土元素的掺杂可提升MoSi_(2)体系涂层的高温抗氧化性能,但稀土元素Y对于MoSi_(2)涂层抗氧化性能的影响机理还尚未明确。以Nb-Si基合金为基体,采用放电等离子烧结技术(SPS)在其表面制备Y掺杂(1 wt.%)的33Mo-62Si-5B(at.%)涂层。通过1250℃高温氧化试验,研究涂层的高温氧化行为以及Y对涂层高温抗氧化性能的影响。结果表明:涂层主要由MoSi_(2)、MoB、Mo_(5)Si_(3)和SiO_(2)相构成,Y在涂层中以Y_(2)Si_(2)O_(7)颗粒的形式弥散分布于SiO_(2)相内部。包覆Mo-Si-B涂层的合金样品在氧化试验初期出现质量损失,其100 h后的氧化增重高于包覆Y掺杂Mo-Si-B涂层的合金样品,表明Y掺杂涂层具有更好的高温抗氧化性能。氧化后涂层表面形成由晶态SiO_(2)、硅硼玻璃相(SiO_(2)-B_(2)O_(3))和Y_(2)Si_(2)O_(7)颗粒构成的氧化膜。阐明Y提升Mo-Si-B涂层抗氧化性能的作用机理:在涂层表面优先形成的Y_(2)O_(3)加速了晶态SiO_(2)和硼硅氧化膜的形成,随后形成的Y_(2)Si_(2)O_(7)阻碍了O的内扩散,使Y掺杂Mo-Si-B涂层抗氧化性能得到提高。Nb-Si based ultra-high-temperature structural materials exhibit high melting points and excellent mechanical properties at high temperatures,which are research focus areas of structural materials for next-generation aero engines.However,the high-temperature oxidation resistance of Nb-Si based alloys is poor because non-protected Nb-containing oxides are spontaneously produced without the formation of a protective oxide scale during oxidation.Because of the formation of a continuous and dense SiO_(2)oxide scale,MoSi_(2)-based coatings are expected to be protective coatings for Nb-Si-based alloys.However,it suffers from pest oxidation at temperatures between 400℃and 600℃.To avoid pest oxidation of MoSi_(2),B was introduced to form a continuous and dense borosilicate(B_(2)O_(3)-SiO_(2)).Borosilicate has higher fluidity than SiO_(2),which can accelerate the formation of the oxide scale and improve the intermediate-temperature oxidation resistance of the MoSi_(2)coating.Studies have shown that rare-earth elements,including Y,can improve the oxidation resistance of materials.However,the effect of Y on the oxidation resistance of Mo-Si-B coatings remains unclear.In this paper,Nb-Si based alloys were used as substrates,and spark plasma sintering(SPS)was employed to prepare 33Mo-62Si-5B(at.%)and Y-doped Mo-Si-B coatings on Nb-Si-based alloys.The phase constitution and microstructure of the coatings were characterized by X-ray diffraction and scanning electron microscopy,respectively.The presence of Y in the coating was confirmed by transmission electron microscopy and selective electron diffraction patterns.Subsequently,the high-temperature oxidation behavior and effect of Y on the high-temperature oxidation resistance of the coatings were studied during high-temperature oxidation experiments at 1250℃for 100 h.The results showed that the Mo-Si-B and Y-doped Mo-Si-B coatings had low porosities of 0.46%and 0.56%,respectively.Both coatings consisted of MoSi_(2),MoB,Mo_(5)Si_(3)and SiO_(2).Mo_(5)Si_(3)and SiO_(2)were de

关 键 词：放电等离子烧结 Mo-Si-B涂层 Y掺杂 高温抗氧化性能 

分 类 号：TG174[金属学及工艺—金属表面处理]