The Preparation And Research Of High-temperature Resistant Coatings With Low Infrared Emissivity

With the quick development of infrared-detection technology,a number of infrared stealth technologies have been proposed around the world.The infrared low emissivity coating occupies an important position in infrared stealth technology due to their low emissivity,cheap cost and simple process.However,with the continuous development of aerospace technology,the aircraft's height and speed increase rapidly,and its exterior surface temperatures also increases.This further increases the temperature requirements for low infrared emissivity coating.At present,there are many reports about high-temperature resistant coatings,but these research seldom involve to the infrared stealth performance.In this paper,the high-temperature resistant coatings with low emissivity was prepared via screening the high-temperature organic binder,low emissivity pigment and black pigment.The specific research content and results of this paper were as follows:To begin with,by comparing the properties of commonly used binders and organic silicone resin,an organic silicone resin was selected as a high-temperature adhesive.Secondly,the effects of different kinds of low emissivity pigments on the high-temperature resistance of coatings were studied.After being heated at 600?for1h,the emissivity of the coating with flake aluminum pigments is as low as 0.27.Therefore,the aluminum flakes can be used as the high-temperature pigments with low emissivity.Besides,the heat resistance mechanisms of Al/organic silicone resin coating was analyzed.It was found that the thermal degradation of the resin matrix and the thermal expansion size(?L)mismatch between the coating and substrate were the main reasons for the coating failure at high temperatures.Thirdly,the effect of commonly used black pigments on the high-temperature performance of Al/organic resin coatings were discussed.The addition of copper chrome black can reduce the lightness(L*)of the coating without decreasing its high-temperature performance.Thus,it can be used as the high-temperature resistant black pigment to adjust the L* of Al/organic silicone resin coating.Finally,the influence of the relative content of aluminum pigments and copper-chromium black pigment on the high-temperature resistance properties ofcoating were studied.When the mass ratio is 7:3,the coating has the low L* of 71 at room temperature and the emissivity is 0.32.Besides,it can withstand heat treatment at500? for one hour.Thus,a high-temperature resistant coating with low infrared emissivity was obtained.