Solid particle erosion resistance of thermally sprayed functionally graded coatings for polymer matrix composites

Thermally sprayed functionally graded coatings based on a polyimide matrix filled with varying volume fractions of WC–Co have been investigated to improve the erosion and oxidation resistance of polymer matrix composites. A study of the coatings' effectiveness as erosion barriers was accomplished through a statistical analysis of the results of solid particle erosion testing of coated and uncoated polymer matrix composite (PMC) samples using a design of experiments (DoE) approach. Two coating systems and a control sample were evaluated in a randomized test matrix. The coatings were tested at room temperature and 250 °C, using an alumina erodent impacting the coatings at a speed of 100 m/s at angles of 20° and 90°. In general, as the angle of incidence of the eroding material increased from 20° to 90° the volume loss increased. Erosion volume loss at 250 °C was approximately twice that at room temperature.