MoSi₂ coatings are prepared using spent and commercial MoSi₂ powders as raw materials to protect niobium (Nb) substrate by spark plasma sintering (SPS) technique, and the microstructure and oxidation resistance of the coatings at 1500 °C are investigated. Results showed that obvious pores are found in MoSi₂ coating using commercial MoSi₂ (MC coating) after SPS while MoSi₂ coating using spent MoSi₂ (MS coating) is dense with low porosity. (Mo,Nb)₅Si₃ diffusion layer is generated between MS coating and the substrate with no gap or cracks, showing excellent metallurgical bonding. After long‐term oxidation at elevated temperature, pores and exposed Mo₅Si₃ can be observed in the oxide scale of MC coating, while dense and complete oxide scale is obtained by MS coating. Lowest mass gain (2.78 mg cm⁻²) is acquired by MS coating after oxidation at 1500 °C for 40 h because SiO₂ oxide scale is completely formed on the dense and bentonite‐containing coating, blocking the diffusion of oxygen at high temperature. Compared with MC coating, no further oxidation occurs inside the MS coating or substrate, exhibiting better high‐temperature oxidation resistance.

中文翻译：

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废MoSi2基材料在铌上二硅化钼涂层的显微组织表征和抗氧化性能

以废旧和商业化的MoSi ₂粉末为原料，通过火花等离子体烧结（SPS）技术制备MoSi ₂涂层，以保护铌（Nb）基材，并研究了该涂层在1500°C时的微观结构和抗氧化性。结果表明，明显孔隙中的MoSi发现₂使用市售的MoSi涂覆₂ SPS之后（MC涂层），而的MoSi ₂涂层使用花费的MoSi ₂（MS涂覆）是致密的具有低孔隙率。（Mo，Nb）₅硅₃在MS涂层和基材之间产生无间隙或裂纹的扩散层，显示出优异的冶金结合。在高温下长期氧化后，在MC涂层的氧化皮中可以观察到孔和暴露的Mo ₅ Si ₃，而通过MS涂层可以获得致密而完整的氧化皮。在1500°C氧化40 h后，通过MS涂层获得的最低质量增益（2.78 mg cm ^-2）是因为SiO ₂氧化皮在致密且含有膨润土的涂层上完全形成，从而阻止了高温下氧气的扩散。与MC涂层相比，MS涂层或基材内部不会发生进一步的氧化，表现出更好的高温抗氧化性。