Abstract: The WC+Ni base selffluxing alloy coating was fabricated by plasma sprayingand then remelted in furnace. The results show that, after being remelted, the coating's morphology changes from laminar structure containing some pores and unmelted particles to dense crystal structure, and the adhesion between coating and substrate transforms from mechanical combination to chemicometallurgical reaction combination, so the coating's cohesive strength and adhesive strength are improved remarkably. The remelted coating consists of γ-Ni, Ni-B(Ni2B), 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 solidification process, and the amorphous crystallizes after remelting process.
详情信息展示
DOI:10.19476/j.ysxb.1004.0609.2001.01.025
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
向兴华 刘正义 陈康年 李尚周
华南理工大学机电工程系!广州510640
摘 要:
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 (Ni2 B) , 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。
Influence of remelting in furnace on microstructure of plasma sprayed WC+Ni base self-fluxing alloy coating
Abstract:
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, the coating's morphology changes from laminar structure containing some pores and un melted particles to dense crystal structure, and the adhesion between coating and substrate transforms from mechanical combination to chemico metallurgical reaction combination, so the coating's cohesive strength and adhesive strength are improved remarkably. The re melted coating consists of γ Ni, Ni B (Ni 2B) , Cr B (CrB) , Ni Si (Ni 5Si 2) 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 solidification process, and the amorphous crystallizes after re melting process. [
Fig.4 Fracture surface morphologies of WC+Ni base self-fluxing alloy coating (a) —Ni base alloy component in plasma sprayed coating; (b) —Ni base alloy component; (c) —WC component in remelted coating
图5 Ni基WC型自熔合金重熔层与38CrMoAl基材的结合界面形貌
Fig.5 Coherent interface morphologies between remelted coating and steel substrate (a) —Optical photograph; (b) —SEM photograph
为涂层成分沿晶界向钢基材内部扩散。
表1 炉熔Ni基WC型合金涂层与38CrMoAl基材结合界面区域各组织的成分
Table 1 Composition of interface zones between remelted coating and steel substrate (mass fraction, %)