Ice formed on radome surfaces causes communication disruption due to radio-frequency interference (RFI), which reveals the importance of de-icing systems for radomes. As a radome de-icing application, in this work, carbon nanotube (CNT) thin films were fabricated using a spray-coating method, and influence of process parameters on RF transmittance and electrothermal properties was investigated. With the increase of spraying time, sheet resistance of the fabricated film decreases, which results in a decrease of the RF transmittance and improvement of the heating performance. Also, the de-icing capability of the fabricated CNT film was evaluated at –20oC, and efficient removal of ice under cold conditions was demonstrated.

The mechanism in which the coatings made by thermal spraying adhere to the substrate is in most cases of a mechanical nature, thus being dependent on the morphology of the substrate surface. This paper study how the texture of the substrate influences the behavior of dry sliding wear, a behavior based on the adhesion to the substrate of the analyzed coatings. For this purpose, a Co – base powder, was chosen for atmospheric plasma spraying. For the substrate, a rectangular profile made of low-alloy steel was chosen, the surface of which was textured by mechanical abrasion, in order to obtain different degrees of roughness: sample S1 – Ra1 = 1.59 µm, sample S2 – Ra2 = 2.32 µm, sample 3 – Ra3.1 = 1.25 μm, Ra3.2 = 3.88 μm. In the case of sample 3, the texturing was done on one direction, with an elongated profile, so that the effect of the main direction of dry sliding wear on the quality of the coating could be studied. The tests were performed on an Amsler test machine, at constant load, for 1 hour. The samples were mounted in a fixed position, and the wear occurred on the basis of the rotation of the metal disc, without lubrication. It was found that the coating of sample 1 was the most affected, resulting even a partial delamination, and the best behavior was recorded in the case of sample 3.1.

Cold spraying as a low-temperature coating deposition method is intended for thermally sensitive materials. Due to its precise temperature control, it limits the formation of structural defects, and can therefore be easily applied to spray corrosion protective coatings made from metal or metal-ceramic powders. However, the formation of pure ceramic coatings with the use of cold spraying is still not so common. Titanium dioxide is one of the most interesting ceramics due to its photocatalytic properties. Nevertheless, these types of coating materials usually work in a corrosion favoring humid atmosphere. In the presented paper, amorphous TiO2 powder was deposited onto aluminum alloys and steel substrates and then submitted to potentiodynamic corrosion tests in a 3.5 wt.% NaCl solution. The as-sprayed coating showed phase transition from amorphous TiO2 to anatase, and also revealed porosity. As a result, electrolytes penetrated the coating and caused undercoating corrosion in the tested environment of an aqueous NaCl solution. The analysis of the potentiodynamic curves showed that the presence of the coating decreased corrosion potential on both substrates. It arose from the mixed phases of TiO2, which consisted of photocathode – amorphous material and photoanode – crystalline anatase. The phase mixture induced the galvanic corrosion of metallic substrates in the presence of electrolytes. Moreover, pitting-like corrosion and coating delamination were detected in aluminium alloy and steel samples, respectively. Finally, the corrosion mechanism of the titanium dioxide coatings was characterized and described.