Formulating Infrared Coatings for Defence Applications

Relevant physical laws governing the response of coatings to solar and infrared radiation have been reviewed. The reflection of infrared radiation by a paint is controlled primarily by the refractive index and particle size of the pigments in the coating. Pigments have been evaluated for reflectance, transparence and hiding power in the near infrared region, and guidelines for pigment selection for various applications given in terms of their optical properties in the near infrared region. Raw materials selection, manufacture and evaluation of coatings have been discussed with respect to tailoring infrared reflectance. By employing the principles developed herein and using pigments with appropriate properties, organic coatings have been developed which are consistent with the visible colour requirements of the Australian and US Navies. Significant increases in the reflection of infrared radiation have been demonstrated by the new formulations. The need for a very clear understanding of the threat systems and the operational conditions of service platforms has been emphasised. It is only with this understanding that optimum paint schemes can be devised. However, it can be stated that the use of the solar infrared reflecting paints described herein would reduce conspicuity of isolated platforms to surveillance and seeker systems operating in the mid and far infrared without detriment to visual camouflage characteristics. Emissivity, Absorption, Coating systems, Thermal infrared, Near infrared, Paints, Reflectance