炉熔处理对等离子喷涂Ni基WC型自熔合金涂层组织形态的影响

摘要

The WC+Ni base self-fluxing alloy coating was fabricated by plasma spraying and then re-melted in furnace. The results show that, after being re-melted, th e coating's morphology changes from laminar structure containing some pores and un-melted particles to dense crystal structure, and the adhesion between coatin g and substrate transforms from mechanical combination to chemico-metallurgical r eaction combination, so the coating's cohesive strength and adhesive strength ar e improved remarkably. The re-melted coating consists of γ-Ni, Ni-B(Ni 2B), Cr-B( CrB), Ni-Si(Ni5Si2) and WC phases that are alike the one of plasma sprayed coating. A little amorphous phase lies in the plasma sprayed coating due to the rapid sol idification process, and the amorphous crystallizes after re-melting process.%研究了等离子喷涂Ni基WC型自熔合金涂层炉熔处 理前后的组织形态。 结果表明， 经重 熔处理后， 涂层由富含孔隙、 未熔颗粒的层状结构转变为致密的结晶组织结构， 涂层与 基材 由机械咬合结合转变为冶金反应扩散结合， 涂层的内聚强度和涂层/基材的结合强度都得以 显著改善。 涂层的相组成在重熔前后变化不大， 均主要由γ-Ni固溶体相， Ni-B(N i2B)， Cr-B (CrB)， Ni-Si(Ni5Si2)和WC硬质相等组成。 由于等离子喷涂是 一种快速 凝固工艺， 在喷涂态涂层中形成了部分非晶相， 经重熔处理后， 非晶相发生完全晶化。