立方氮化硼含量对等离子喷焊层Ni60B+cBN/Ti组织与性能的影响

Effect of cBN Content on Microstructure and Properties of Ni60B+cBN/Ti Coatings Prepared by Plasma Spray Welding

采用扫描电镜、能谱仪、X射线衍射仪和显微硬度计等研究了cBN含量对Q235钢表面Ni60B+cBN/Ti等离子喷焊层显微组织与性能的影响。结果表明:喷焊层可分为熔合区、中部枝晶区和上部含cBN颗粒区。喷焊层中部枝晶区的主要物相为(Ni,Fe)、FeNi_3、(Fe,C)及富铬碳化物,喷焊层上部含有cBN颗粒区的主要物相为(Ni,Fe)、FeNi_3、NiTi、cBN、Cr B、TiB_2、TiB和CrN。随着cBN含量的增加,喷焊层表面硬质颗粒相增多。喷焊层表面的显微硬度随cBN含量的增加而增大,但cBN含量过多会导致其连接性变差,喷焊层会出现气孔及cBN颗粒脱落现象,从而降低喷焊层的力学性能。

The influences of cBN content on the microstructure and properties of Ni60B+cBN/Ti plasma spray welding layer on the surface of Q235 steel were studied by using scanning electron microscope(SEM),energy disperse spectrometer(EDS),X-ray diffraction(XRD)and microhardness meter(MM)techniques.The results show that the spray welding layer can be divided into three zones,namely fusion zone,middle dendrite zone and upper zone with cBN grain.The main phases in the middle dendrite zone of the spray welding layer are(Ni,Fe),FeNi3,(Fe,C)and chromium-rich carbides.The main phases in the upper cBN grain-containing zone of the spray welding layer are(Ni,Fe),FeNi3,NiTi,cBN,CrB,TiB2,TiB and CrN.The hard particle phases on the spray welding layer surface gradually increase with increasing cBN content.The microhardness of the spray welding layer surface increases with increasing cBN content,but excessive cBN content can lead to the degradation in its connectivity.The spray welding layer generates the appearance of pores and falling-off of cBN particles,which can reduce the mechanical properties of the spray welding layer.