Multi-layered surface coatings of refractory ceramics prepared by combined laser and flame spraying

Hybrid laser-flame spraying provides a new opportunity for depositing multi-layered surface coatings with a range of densities and microstructures. In the present study, multi-layered zirconia-alumina coatings of various densities and thicknesses were applied onto an alumina-based refractory substrate by the hybrid laser-flame spraying method, using several sets of process parameters. The microstructures and porosity data for the coatings were characterized by scanning electron microscopy and the image analysis method. The results showed that the combined laser and flame spraying technique was a practicable approach for preparing multi-layered coatings. The relationships between the coating microstructure, process parameters and types of powder materials are discussed.