氧乙炔火焰喷焊制备自熔性合金涂层及其性能研究

目的研究镍基自熔性合金喷焊涂层成形机理,比较不同合金材料制备涂层的综合性能,以获得综合性能最佳的喷焊材料。方法以四种不同成分的镍基自熔性合金粉末作为喷焊材料,通过氧乙炔火焰在45钢基材表面进行喷焊。使用金相显微镜、X射线衍射、扫描电子显微镜等对喷焊层进行显微结构分析,并利用维氏硬度计、磨损试验机等对喷焊涂层性能进行对比分析。结果氧乙炔火焰制备的涂层与基体呈现良好的冶金结合,涂层和基体在喷焊过程中发生元素扩散,生成了金属间化合物,基体的整体性能有显著改善。随着材料中Cr、B、Si等合金元素含量的增加,喷焊时涂层中生成的BCr、Ni17Si3等共晶硬质相含量上升,促使涂层的显微硬度、耐磨性能等得到显著提升。其中,Ni60A涂层提升最为显著,其涂层硬度相当于基体硬度的2.5倍,耐磨性为基体的18.1倍。Ni25A涂层提升最小,其显微硬度是基体的1.3倍,耐磨性是基体的6.6倍。结论喷焊状态下的Ni60A涂层与基体冶金结合良好,涂层表面质量好,涂层性能最佳。

Properties of Self-fluxing Alloy Coating Prepared by Oxy-Acetylene Flame Spray Welding

The work aims to study forming mechanism of nickel-based self-fluxing alloy coating prepared by spray welding, and compare overall properties of coatings made from different alloy materials, and find out the spray welding material exhibiting the best overall properties. With four pieces of nickel-based self fluxing alloy powder made of different components as spray welding materials, spray welding was applied to the surface of 45# steel substrate with oxygen acetylene flame. Microstructures of the spray welding layers were analyzed with metallographic microscope, X-ray diffractometer, scanning electron microscope, etc., and properties of the spray welding coatings were comparatively analyzed with Vickers hardness tester and wear tester. Good metallurgical bonding could be obtained between coatings prepared with oxyacetylene flame and substrate. Elemental diffusion occurred on the coatings and substrate during the process of spray welding, intermetallic compound was produced, and overall properties of the substrate were improved remarkably. With the increase of alloy elements including Cr, B and Si in the materials, content of eutectic carbide phases including BCr and Ni17Si3 in the coatings increased during spray welding, thus microhardness and wear resistance were of the coatings were significantly improved. Among all, those of Ni60A coating were improved most significantly, its hardness was 2.5 times as high as that of the substrate, wear resistance was 18.1 times as high as that of the substrate; and those of Ni25A coating were improved least, its hardness was 1.3 times as high as that of the substrate, and wear resistance was 6.6 times as high as that of the substrate. The Ni60A coating subject to spray welding has good metallurgical bonding with the substrate, exhibits good surface quality and best coating properties.