| 引用本文: | 靳鸣,邵蔚,贺定勇,陈广辉,谈震,郭星晔,周正.放电等离子烧结Y掺杂Mo-Si-B涂层的高温抗氧化性能[J].中国表面工程,2024,37(4):134~141 |
| JIN Ming,SHAO Wei,HE Dingyong,CHEN Guanghui,TAN Zhen,GUO Xingye,ZHOU Zheng.High Temperature Oxidation Resistance of Y-doped Mo-Si-B Coating by Spark Plasma Sintering[J].China Surface Engineering,2024,37(4):134~141 |
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| 摘要: |
| 稀土元素的掺杂可提升 MoSi2体系涂层的高温抗氧化性能，但稀土元素 Y 对于 MoSi2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 1 250 ℃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 MoSi2、MoB、Mo5Si3和 SiO2 相构成，Y 在涂层中以 Y2Si2O7颗粒的形式弥散分布于 SiO2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 SiO2、硅硼玻璃相(SiO2-B2O3)和 Y2Si2O7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 Y2O3 加速了晶态 SiO2 和硼硅氧化膜的形成，随后形成的 Y2Si2O7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。 |
| 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 |
| DOI：10.11933/j.issn.1007-9289.20230427001 |
| 分类号:TG174 |
| 基金项目: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 |
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| High Temperature Oxidation Resistance of Y-doped Mo-Si-B Coating by Spark Plasma Sintering |
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JIN Ming，SHAO Wei，HE Dingyong，CHEN Guanghui，TAN Zhen，GUO Xingye，ZHOU Zheng
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Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124 , China
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| Abstract: |
| 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 SiO2 oxide scale, MoSi2-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 MoSi2, B was introduced to form a continuous and dense borosilicate (B2O3-SiO2). Borosilicate has higher fluidity than SiO2, which can accelerate the formation of the oxide scale and improve the intermediate-temperature oxidation resistance of the MoSi2 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 1 250 ℃ 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 MoSi2, MoB, Mo5Si3 and SiO2. Mo5Si3 and SiO2 were derived from the oxidation of MoSi2 during SPS. In addition, Y was segregated in the interior of SiO2 in the form of Y2Si2O7 in the Y-doped Mo-Si-B coatings. During the initial stage of the oxidation experiment, the Nb-Si-based alloy coated with the Mo-Si-B coating had weight loss owing to the volatilization of MoO3. The oxidation weight increase of the alloy coated with Mo-Si-B coating after 100 h was 0.421 mg cm?2 , which was higher than that of the alloy samples coated with Y-doped Mo-Si-B coating (0.351 mg·cm?2 ). Moreover, the oxidation rate constant (kp) of the Mo-Si-B coating was 2.0×10?3 mg2 ·cm?4 ·h?1 , which was also higher than that of the Y-doped Mo-Si-B coating. The oxidation kinetics of the coatings indicate that the Y-doped coating has better high-temperature oxidation resistance. After oxidation, an oxide scale was formed on the surface of the Mo-Si-B coating, consisting of crystal SiO2 and borosilicate glass. Additionally, Y2Si2O7 emerged in the oxide scale of the Y-doped Mo-Si-B coating. Owing to its low Gibbs free energy, Y2O3 was preferentially formed on the surface of the Y-doped Mo-Si-B coating. Y2O3 particles provided nucleation points, accelerating the formation of crystalline SiO2 and borosilicate glass. The subsequent formation of Y2Si2O7 prevented the inward diffusion of O and improved the oxidation resistance of the coatings. This study proposes a new method for oxidation protection of Nb-Si-based alloys and promotes the application of Nb-Si-based alloys in aero-engine high-pressure turbine blades. |
| Key words: spark plasma sintering Mo-Si-B coating Y-doped high-temperature oxidation resistance |
