Flame-sprayed coatings as de-icing elements for fiber-reinforced polymer composite structures: Modeling and experimentation

The development of embedded de-icing elements for polymer-based composite materials, coupled with mathematical models that describe their performance, is of interest to the aerospace, communications, and energy industries. Nickel-chromium-aluminum-yttrium (NiCrAlY) coatings were deposited on to fiber-reinforced polymer composite (FRPC) plates by using a flame spraying process. Electric current was supplied to the metal alloy coatings to generate energy by way of Joule heating (or resistive heating) and to enable the coatings to act as heating elements for the FRPC structures. De-icing tests were performed at ambient temperatures of −5 °C, −15 °C, and −25 °C, after liquid water was sprayed on the samples. Heat transfer models were developed to predict the heating and melting times of the ice during the de-icing process with the flame-sprayed coatings. The models were based on the separation of variables method for a finite length-scale melting problem and Stefan's problem applied to a semi-infinite medium. It was found that a coating that was on the order of 100 μm thick was effective for melting accumulated ice on polymer composite structures that were exposed to cold environments. The results of the finite length-scale model and its agreement with experimental data suggest that a heat conduction model based on the separation of variables method may be applied to free boundary problems to predict phase change phenomena induced by thermal-sprayed coatings.