Composite Damping Ceramic Coatings by Polymer Impregnation

Abstract

The interest in the use of thermal barrier ceramic coatings as damping treatments has recently arisen since they were shown to provide sufficient additional damping. Ceramic coatings can be applied mainly by either Air Plasma Spraying (APS) or Electron Beam - Physical Vapour Deposition (EBPVD). APS was used to deposit the specimens studied here. Previous research has shown that it is possible to enhance their damping effectiveness by tailoring the deposition parameters. This paper presents further work aimed at improving their damping effectiveness significantly by introducing a second material in the ceramic coating; thus creating a composite system. This paper covers the experimental findings of impregnating a ceramic damping coating with a number of commercially available polymeric materials. The most promising case of a type of Polyurethane provided over 40% improvement and was selected for further tests at various temperatures, ranging from -40 to 150 􀁱C. Furthermore, the damping and stiffness of ceramic coatings present amplitude-dependent behaviour which was also taken into consideration when evaluating the composite system. Finally, the paper concludes with a discussion of these promising findings as well as planned research into understanding the physical mechanisms dissipating energy in this composite material.