Kinematic Viscosities of High-Temperature Materials Used in Plasma Spraying
Abstract:A simple analytical model based on the law of conservation of energy was developed to estimate the kinematic viscosity of high-temperature materials. An energy balance between the kinetic, viscous dissipation, and surface energies of high-speed molten droplets and the splats formed after impact and spreading was conducted to produce a nondimensional relationship between kinematic viscosity and the maximum spread factor of the splat. The dimensional kinematic viscosities of a wide variety of high-temperature materials were determined and comparisons with experimentally measured viscosities were conducted. It was found that the predictions of the model agreed to within one order-of-magnitude of experimentally measured values. Experimental data for high-temperature ceramics such as yttria-stabilized zirconia were unavailable for comparison. However, the agreement between the model and experimental values of kinematic viscosity observed for alumina, coupled with the monoclinic fluorite structure and high density of zirconia, suggested that its kinematic viscosity was probably much lower than that of alumina, as predicted by the analytical model.
Document Type: Research Article
Affiliations: 1: Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada T6G 2G8 2: Department of Mechanical and Industrial Engineering, Center for Advanced Coatings Technology, University of Toronto, Toronto, ON, Canada M5S 1A4
Publication date: June 1, 2011