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用扩散渗法在Nb/NbCr2合金表面制备硅化物涂层,研究了基体合金和涂层在1250℃的氧化行为。结果表明:在Nb/NbCr2合金表面渗Si所得硅化物涂层由(Nb,Cr)Si2和(Cr,Nb)Si2两相组成,过渡层为(Nb,Cr)5Si3,涂层的生长动力学服从抛物线规律。基体合金在1250℃氧化形成的氧化膜为Nb2O5和CrNbO4交替分布的疏松组织,与基体有剥离现象。渗Si涂层在1250℃氧化形成的氧化膜较为致密完整,与残留涂层结合良好,为SiO2和CrNbO4混合氧化膜,改善了合金的高温抗氧化性能。
The silicide coating was prepared on the surface of Nb / NbCr2 alloy by diffusion infiltration method. The oxidation behavior of the base alloy and coating at 1250 ℃ was studied. The results show that the silicide coatings on the surface of Nb / NbCr2 alloy consist of (Nb, Cr) Si2 and (Cr, Nb) Si2 two phases and the transition layer is (Nb, Cr) 5Si3. The growth kinetics Obey parabolic law. The oxide film formed by oxidation of the base alloy at 1250 ℃ is a loose structure with alternating distribution of Nb2O5 and CrNbO4, which is peeled off from the matrix. The oxide film formed by the infiltration of Si coating at 1250 ℃ is dense and complete, and it is well mixed with the residual coating, which is a mixed oxide film of SiO2 and CrNbO4, which improves the high temperature oxidation resistance of the alloy.