铸钢表面复合涂层的微观组织分析

Analysis on Microstructure of Surface Composite Coating on As-cast Steel

通过铸造反应合成技术在铸钢表面形成Tic／Ni3Al复合涂层，采用扫描电镜（SEM）和透射电镜（TEM）研究了复合涂层及界面的微观组织形貌。结果表明：TiC含量明显影响表面复合涂层及界面微观形貌。复合涂层的微观组织为1～3μm的TiC颗粒呈球形镶嵌在Ni3Al基体上，随着TiC含量的提高，颗粒尺寸略有长大、分布更均匀、涂层更致密，且涂层与钢基体界面为良好的冶金结合。在TiC含量〈25％时，表面复合涂层组织不致密，涂层与钢基体界面处存在较多的裂纹和孔洞。

A TiC/Ni3Al surface coating was fabricated on the steel substrate by casting route with reaction synthesis. The microstructure and interface morphology of the coating were studied by using scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The results show that content of TiC has an obvious effect on microstructure and interface morphology of the coating. The microstructure of the coating is TiC particulates with diameters of 1 -3 μm mounted in Ni3Al. With increasing TiC content, TiC particulates have slightly growth and more uniform distribution. The better metallurgical bonding between the coating and steel substrate is obtained as well.. When content of TiC is less than 25wt%, the microstructure of the coating is not dense and there are a large number of cracks and pores in the interface.