Airbrushing: a novel method for preparation of high-emissivity black coating for infrared measurement

The reliability of infrared (IR) imaging is strongly dependent on the surface emissivity of the investigated object. Achieving near-unity emissivity is essential to IR measurement accuracy. To meet this requirement, black paint coatings are commonly applied onto the studied samples. However, there is a lack of a systematic study of the coating preparation for IR measurements. In this work, a new procedure is developed for the preparation of black paint coatings using the cost-effective airbrush tool. With this novel method, it can achieve black paint coatings as thin as ≈3 µm or thicker, depending on the number of layers. The coatings are homogeneous and with excellent adhesion to the substrate. Furthermore, the coatings can be entirely removed from the substrate using conventional laboratory solutions. The coatings exhibited an average emissivity of ≈0.95 within the 0.5–2.5 µm wavelength range. The quality of the coatings is validated by directly measuring the magnetocaloric response of a commercially available material, which is in excellent agreement with the supplier's datasheet. In this way, a novel affordable black coating method is showcased, which can be applied on a wide variety of samples for IR measurements, broadening the possibilities for IR characterizations.