Effect of oxygen content on the reaction course and radiation performance of Si/MTV system

Abstract

Large numbers of studies show that silicon (Si) will not be oxidized into silicon fluoride (SiF4) and silicon oxide (SiO2) in the MSiTV (Magnesium Silicon Teflon Viton) system, which causes a waste of energy. The limited efforts in this paper focused on adding the oxidant barium nitrate (Ba(NO3)2) to the MSiTV pyrotechnics to study the oxidation reaction course and the effect of oxygen content on the radiation combustion performance. The infrared radiation of the agent during the combustion process is tested with a Spectraline SC7000 imaging spectrometer, and the combustion performance such as the burning area and radiation temperature is tested by the SC7000 thermal imager. The solid combustion products of the medicament are collected in a vacuum box combustion experiment and tested by infrared spectroscopy for their combustion products. Assumed that the amount of oxygen in the air participating in the reaction is constant. Then the oxygen difference theory (The calculation method is listed at the end of 3.1) can be used to calculate the hypoxia degree of the pyrotechnics and simply predict the oxidation reaction history. The experimental results show that the oxidation sequence of MSiTV compositions can be divided into 3 steps with the increase of oxidant content. The first step is to oxidize the incompletely reacted Magnesium (mg) to Magnesium Oxide (MgO). The radiation performance changes little during this process for the reaction release a lot energy and make up for the mass loss of MTV. The second step is the carbon ash oxidized to generate CO which greatly reduce the emissivity of the agent. The near-infrared radiation (NIR) spectral energies was reduced by up to 33% from 724.2 J/g*sr to 484.8 J/g*sr and the mid-infrared radiation (MIR) spectral energies reduced by up to 27% from 298.0 to 218.6 J/g*sr. The third step is the simultaneous oxidation of Si to SiO2 and Carbon monoxide (CO) to (carbon dioxide) CO2 by excess oxygen. The NIR intensity gradually decreases from 484.8 J/g*sr to 232.3 J/g*sr and the MIR spectral energies decreases from 218.6 J/g*sr to 122.3 J/g*sr for the reduction of MTV content even though the oxidation of Si released much heat. The far-infrared radiation (FIR) spectral energies of the pyrotechnics increased from 29.2 W/Sr to 59.9 W/Sr, an increase of 105% owing to the strong emissivity of Si in FIR. At this moment, the near-middle-far infrared ratio changed from 2.4: 1: 0.15 of MTV to 1.9: 1: 0.5.