Preparation And Research On The Ir Properties Of Low Emissivety Flake Aluminium Powder

Advanced infrared detection technology offers a serious challenge to the infrared stealth property of weapon and equipment. Coated low infrared emissivity coating on the weapon equipment is one of the most common methods for infrared camouflage technology. The flake metal pigment is widely used in low emissivity coating because of its low emissivity, but it has strong metallic luster and high reflectivity of visible light, which is harmful to visible light camouflage. Due to the diversification of modern military war, it is difficult for flake metal pigment to adapt to the need of modern war by simply infrared camouflage. Therefore, to design one kind of material that can be compatible with visible light-infrared absorbing properties would be of great significance for practical applications.In this paper, the Al/Bi₂O₃ composite was prepared via coating Bi₂O₃ particles on surface of flake aluminum by direct precipitation method. The brown Al/MnO2 composite pigment was prepared via coating manganese oxide particles on surface of flake aluminum. Technological parameters like the dropping speed rate of precipitant, reaction time, calcination temperature and so on were discussed. The morphology, crystal phase structure, the thermal infrared emissivity and color parameters of the composite powder were respectively analyzed by SEM, XRD, Fourier infrared spectrometer and burnish meter.The results have shown that the aluminum is well coated after calcined at 450℃for 2h when the precipitation reaction temperature is 40℃, n(Bi³⁺) to n（Al） ratio is 0.2:1, the dropping speed rate of precipitant is 0.3ml/min. The lightness L* can be decreased by 13.4 as compared to the uncoated aluminum, but the infrared emissivity is only increased 0.05. The results have shown that the aluminum is well coated after calcined at 350℃for 2h when the reaction temperature is 30℃, the SDS is used as surfactant, the molar ratio of KMnO₄ to Al equals to 0.1:1, the reaction time is 2h. The emissivity of the composite powder is 0.63, while the Lightness is 50.3. Comparing the original flake aluminum pigments, the lightness L* of Al/MnO2 composite powder can be decreased by 27.3, but the infrared emissivity is only increased 0.14. Both composite powders make visible compatible stealth compatible with infrared stealth.Research shows that: the raw materials, preparation methods and technological parameters have a great influence on the morphology and structure of the composite powder particles, and finally affects the compatible camouflage performance of the composite pigment. The nuclear shell structure powder paint that we finally get can effectively reduce the lightness of the normal aluminum, and has low infrared emissivity. In this paper the research also has certain significant exploring and reference values for the related composite pigment engineering preparation.