含稀土真空熔结镍基合金涂层的界面组织和分布特性

Interface structure and distribution characteristics of vacuum fusion sintered Ni-based alloy coating containing rare earth element

通过研究了真空熔结镍基合金涂层纵截面的微观组织、相结构、以及合金元素和显微硬度的分布特征,结果表明,稀土(Ce+La)改善了N i60涂层的组织,使针状相改变成了小球状相,加强了界面的冶金结合。N i60+RE涂层还析出了新的第二相WC、N i2B、N iB和Cr6.5N i2.5S i。稀土阻碍了涂层中N i、Cr、S i等原子向母材的扩散和母材中Fe原子向涂层的扩散,提高了涂层中N i、Cr、S i等元素的含量,降低了Fe的含量,减轻了碳钢母材中的Fe对合金涂层的"稀释"作用。稀土还明显地提高了合金涂层的显微硬度,两种N i60合金涂层显微硬度的最大值都出现在距涂层表面的0.4 mm处。

The microstructure, phase structure, and distributing characteristics of alloy elements and microhardness of vertical section of vacuum fusion sintered Ni-based alloy coatings were studied in this paper. The results showed that rare earth elements (Ce+La) improved structure of Ni60 coating, needle-shaped phase transformed to small globular-shaped phase, and the metallurgical binding of interface between the steel matrix and coating was reinforced. New second phases WC, Ni2B, NiB and Cr6.5Ni2.5Si precipitated in Ni60+RE coating. Rare earth elements held back the diffusion of Ni, Cr and Si atoms from coating to steel matrix and Fe atom from steel matrix to coating, and alleviated dilution function of Fe atom from steel matrix to Ni-based alloy coating. Rare earth elements increased Ni, Cr, and Si contents, and decreased Fe content in the coating too. The microhardness of Ni-based coating could apparently be enhanced by introduction of rare earth elements, and microhardness values of two kinds of coating reached their maximum values at 0.4 mm near by coating surface.