Microstructure of Fe-Based Alloy Composite Coatings Reinforced by Ti (C0.3 N0.7) Particles Through Laser Cladding Technology

Fc-bascd alloy layer reinforced by Ti(C, N) particles was produced on the surface of cast steel. X-ray diffraction (XRD) was used for phase identification in the composite coating. The microstructure of laser cladding layer was analyzed by means of optical microscope (OM), electron probe microscope analyzer (EPMA), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that Ti(C0.3 N0.7) particle is introduced by an in-situ metallurgical reaction of TiN particle and graphite powder in the process of laser cladding. The shape of lots of Ti(C0.3 N0.7) particle is irregular. The sizes of Ti(C0.3 N0.7) particles range from 0.1 to 6.0 μm, and they arc dispersed evenly in the matrix, which is fine dendritic or cellular crystal. A new kind of phase named Ti(C0.3 N0.7) particles arc tightly bonded with α-Fe microstructure, and there is a clean and smooth phase interface between ceramic reinforcement phase and the matrix.