A scanning electron microscopy study of laser coating microstructures

Investigations were made, using scanning electron microscopy, to examine microstructural features of laser coatings. The scanning electron microscope makes it possible to observe clearly the detail of the structure in the laser-irradiated zone. It is shown that the microstructures in the laser-coated zone have various features, including a dendritic eutectic, dendritic solid solution, and residual graphite, and that the microstructures in the transitional zone are more complex, including cellular dendritic-cellular, dendritic eutectic, planar, and residual graphite. The laser coating process changes the nature of solidification of the coating melt, compared with common solidification.