Study On Anti-oxidation Technology And Infrared Extinction Performance Of Copper-based Smokescreen

Micron-grade copper powder is very easy to oxidize in the humid air.Against disadvantages of micron grade easy oxidation of copper powder,this paper adopts the surface modification technology of bronze powder.Respectively using ethyl orthosilicate(TEOS)and silane coupling agent(KH-550)as the cladding material,the TEOS and KH-550 modified bronze powders were finally made by hydrolytic polycondensation reation under the condition of high water-silicon ratio and temperature.The antioxidant properties of bronze powder were improved after modification.Exothermic peak temperature of TEOS modified bronze powder reduced from 332.2? to 330.1?,and its weight gain rate reduced from 16.5%to 13.7%.The infrared extinction ability of TEOS modified bronze powder was declined.In order to improve the antioxidant properties of bronze powder,preparation technology of cordierite infrared ceramic material was studied.Polymerization reaction was made at high water-silicon ratio,with magnesium nitrate,aluminum nitrate and ethyl orthosilicate as the main body,and with some ionic products as the elements addition,such as Ni,Bi.At the same time,the cordierite sample was also made by solid phase reaction with magnesium oxide,alumina and silica as the main body in the 250?300 r/min ball grinding speed.After the analysis,the infrared absorption peak of cordierite was fouced on far-infrared range(8?14?m),its thermal stability interval was above 400?,and its temperature of crystal shape changing was at 1000?.Secondly,antioxidant properties and infrared extinction performance of bronze powder and its cordierite compound were studied.We found that the initial oxidation temperature of bronze powder and copper-based compound(Ni-doped cordierite)were 290 ? and 320 ? by TG-DTA,and the first exothermic peak temperature(Tm)of these two changed from 166 ?to 320 ?.Membrane method and smoke box method were used to test IR spectrum date of various copper-based materials in this paper.According to the data of surface density(m/S)and mean transmissivity(T)of interfering material,the mass extinction coefficient(?)of all kinds of materials could be calculated.In 3?5?m,the a of bronze powder and its coordination compounds calculated by smoke box methods were 0.29?0.34m2·g-1 and 0.23?0.32m2·g-1.And in the 8?14?m,their mass extinction coefficient were both 0.02m2·g-1.In this paper,in view of the problem of spatial dispersion of copper-based smoke screen materials,a self-designed pneumatic spray test device was used to study the smoke formation characteristics of smoke particles under different smoke nozzle pressure(p).When the nozzle pressure was 0.02MPa,the diffusion angle of the single nozzle smoke screen was 10°?15°while the double nozzle smoke screen was 56°?66°.The results showed that the smoke screen effect of the double nozzle was better.The maximum surface density(Mmax)increased with the increase of time(t),and decreased with the increase of the nozzle pressure(p).