熔焊工艺对自熔合金涂层组织的影响

利用显微镜和X射线衍射仪对感应熔焊、火焰喷焊、等离子堆焊Ni基自熔合金涂层的金相组织、结合面形态、涂层微区成分及焊层合金化学成分进行了分析。研究结果表明，感应熔焊涂层与基体界面出现了白亮带，焊层底部形成了明显的针条状组织，并且涂层中部w（Fe）整体高于粉末本身；火焰喷焊层得到均匀一致的奥氏体和碳化物共晶析出物，涂层与基体也属于冶金结合，扩散熔合区w（Cr）和w（Ni）较感应熔焊涂层的有所降低；等离子堆焊层在快速冷凝过程中生成了树枝状结晶组织，焊层中的C、B、Si、Cr等元素烧损率以等离子堆焊最大，火焰喷焊重熔次之，感应熔焊最小；感应熔焊对基体与涂层界面处Fe原子的激活度最大。

Influence of welding technology on coating microstructure of self-fluxing alloy powders

The microstructures,joint face morphologies,composition of micro spraying area,and chemical composition of coating alloy of Ni-base self-fluxing alloy coating obtained with faradic,autogenous and plasma spraying respectively are studied by means of SEM and X-ray diffraction meter(XRD). The research results indicate that there is white-light band in the interface between the base and coating,the obvious needle-like microstructure is formed,and the Fe-content as a whole is higher than that in the powders in faradic spraying coating; there is uniform austenitic carbide eutectic in autogenous spraying coating,the coatings and the base are metallurgically jointed,and the Cr and Ni content in scattering fusion zone are less than that in faradic melting zone; the dendrite is produced during faster cooling process in plasma spraying coating.The loss of C,B,Si,Cr and other elements in coatings decreases in the order of plasma,autogenous and faradic spraying.The Fe atom activation degree is the strongest on the interface between the coating and base for faradic melting technology.