Abstract

Polymeric composite materials have been used to manufacture both jet engine fan blades and wind turbine blades. The main considerations in the blades design are efficiency, weight, and durability. The blades must be capable of withstanding solid particles impact with no damage. Polymeric composite does not have a good erosion resistance. In this thesis, application of thermal spray coatings on polymeric composite materials has been investigated to improve their erosion resistance. Three different coating materials namely, tungsten carbide-cobalt, martensitic chromium stainless steel, and alumina-titania are chosen because of their excellent abrasion and erosion resistant, good mechanical properties, and relatively low cost. Atmospheric plasma spray is used to deposit the coating on the composite. Composite panels are manufactured using carbon fiber reinforced polymer CFRP using hand layup and autoclave curing. During the layup, a stainless steel mesh is placed on the top of the panel. This metal mesh will protect the composite during coating deposition and serve as an anchor for keeping the coating in place. Different plasma spray processing conditions are tried to have a good coating on the panel. Flatwise tensile tests are performed to measure the adhesion between the composite substrate and coating. It is found that using stainless steel metal mesh makes uniform, high quality coatings with significant adhesion property between composite substrate and coat layer. The solid erosion testing was carried out using air-jet erosion testing (ASTM G76) by hard, angular alumina particles at 30˚, 60˚ and 90˚ impact angle. Different impact angles were measured to demonstrate the erosion regime (ductile or brittle) of each material. In order to determine mechanical properties and microstructure effect, roughness and the hardness of each material have been studied. It is shown that the proposed method of manufacturing can improve significantly the erosion resistance of the polymeric composites.