X. Ma, M. Wang, T. D. Xiao, J. Roth, Inframat Corp., Farminton, CT
The physical and performance properties of a thermal sprayed coating are dependent on both the material chemistry and the process variables of that material. Of particular importance is the microstructure that is delivered. In a traditional or conventional thermal spray process, a coating is formed with microstructural characteristics of coarse micron-sized splats, distinct lamellar boundaries, large unmelted particle inclusions and defective porosity. These typical coating microstructural defects lead to decreased adhesion, cohesion, strain-tolerance, corrosion and wear resistance. In recent years, our attempts have been addressed to manipulating those microstructure features in submicron to nanometer scales. By using submicron and nanometer particles or their agglomerates as feeding materials, we have produced fine-structured thermal sprayed coatings of metal, metal-ceramic and ceramic materials through retrofitting thermal spray processes. As a result, it enables to engineer coating microstructure within individual splats, and achieve multiple desirable coating properties, including high hardness and high toughness. Based on case analyses, we will demonstrate that the fine-structured coatings have unique microstructure features and improved coating properties compared with coarse-structured coatings.
Summary: The physical and performance properties of a thermal sprayed coating are dependent on both the material chemistry and the process variables of that material. Of particular importance is the microstructure that is delivered. In a traditional or conventional thermal spray process, a coating is formed with microstructural characteristics of coarse micron-sized splats, distinct lamellar boundaries, large unmelted particle inclusions and defective porosity. These typical coating microstructural defects lead to decreased adhesion, cohesion, strain-tolerance, corrosion and wear resistance. In recent years, our attempts have been addressed to manipulating those microstructure features in submicron to nanometer scales. By using submicron and nanometer particles or their agglomerates as feeding materials, we have produced fine-structured thermal sprayed coatings of metal, metal-ceramic and ceramic materials through retrofitting thermal spray processes. As a result, it enables to engineer coating microstructure within individual splats, and achieve multiple desirable coating properties, including high hardness and high toughness. Based on case analyses, we will demonstrate that the fine-structured coatings have unique microstructure features and improved coating properties compared with coarse-structured coatings.
