Abstract MoSi2-B4C coatings with different B4C contents were prepared on Nb alloy by spark plasma sintering (SPS) process. Powder mixtures of Mo, Si and B4C were used as the coating starting materials. Besides MoSi2 and B4C phases, small amounts of SiC and MoB are also found in the coatings because of the reactions of Mo, Si and B4C powders during sintering. Compared with single MoSi2 coating, the MoSi2-B4C coatings show better oxidation resistance at 1450 ℃, and dense B2O3-SiO2 oxide scales form after 100 h oxidation. The B4C or MoB in the MoSi2-B4C coatings can serve as the B donor for the formation of B2O3. A slight degradation in the microstructure of the MoSi2-B4C coatings after oxidation is observed, which can be attributed to the presence of an NbB layer in the inter-diffusion zone of the coatings that retards the inward diffusion of Si from the coating into the substrate alloy. The microstructure development and oxidation behavior of the MoSi2-B4C coatings have been discussed.

中文翻译：

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放电等离子烧结MoSi2-B4C涂层反应合成Nb合金氧化保护

摘要 采用放电等离子烧结(SPS)工艺在Nb合金上制备了不同B4C含量的MoSi2-B4C涂层。Mo、Si和B4C的粉末混合物用作涂层起始材料。除了 MoSi2 和 B4C 相外，由于 Mo、Si 和 B4C 粉末在烧结过程中的反应，涂层中还发现了少量的 SiC 和 MoB。与单一的MoSi2涂层相比，MoSi2-B4C涂层在1450 ℃表现出更好的抗氧化性，氧化100 h后形成致密的B2O3-SiO2氧化皮。MoSi2-B4C 涂层中的 B4C 或 MoB 可作为 B2O3 形成的 B 供体。观察到氧化后 MoSi2-B4C 涂层的微观结构略有退化，这可归因于在涂层的相互扩散区​​中存在 NbB 层，该层阻止了 Si 从涂层向内扩散到基体合金中。讨论了 MoSi2-B4C 涂层的微观结构发展和氧化行为。