The Preparation And Performance Representation Of High Precision Nano Porous Silicon Delay Composition

In this paper, we used nano porous silicon/barium chromate delay composition asthe research object, mainly studied the formula, preparation technology and combustionproperties. Firstly, the nano porous silicon powder was prepared by chemical etching method.Secondly, the delay composition ratio by zero oxygen balance theory is8/92(wt%), as thebasis, eight formulas were chosen, which were respectively8/92,14/86,20/80,22/78,24/76,26/74,28/72and30/70. Thirdly, by comparing the manual mixing method and chemicalprecipitation method of the two kinds of mixing methods, chosen the chemical precipitationmethod as the preparation process of nano porous silicon/barium chromate delaycomposition. Then, the preparation technology was optimized by three factors and three levelsorthogonal test to obtain optimum technology, which were the stirring rate of reactionsolution was200r/min, the titration rate was2.013mL/min, and the reaction temperature was60℃. Finally, the nano porous silicon/barium chromate delay composition of eightformulations were prepared by optimum conditions of the chemical precipitation method,assemble and store them according to the requirement. On the basis of the above mentionedexperiments, the burning rate of the eight groups of different formulations were tested in25℃environment. Selected the delay composition with stable combustion and good delayprecision from them to create the following tests: the burning rate test under high and lowtemperature environment; the burning rate test of porous silicon compared with silicon delaycomposition; the effects of assembly density on the burning rate; the effects of storage time onthe burning rate and delay precision. After careful analysis and research, some usefulconclusions were as follows:(1) In25℃environment, burning rate of delay composition formulation of8/92and14/86were not ignited; formulation of20/80was ignited, but the individual could not besustained combustion; the rest of the delay composition were combustion stability. With thegradual increase of porous silicon content in the delay composition, the burning rate sloweddown gradually.(2) Compared with25℃environment, the burning rate of delay composition decreasedin low temperature-15℃environment, to reduce the rate of8%; but in high temperature50℃ environment, the burning rate of increase would be more obvious, to grow12.24%.(3) Under the same conditions compared with ordinary silicon delay composition, thedelay time of nano porous silicon delay composition decreased, as well as the burning rateincreased. Moreover, the burning rate was more uniform, the delay precision was moreaccurate.(4) With the gradual increase of assembly density, the burning rate slowed downgradually. When the pressing density reached a certain degree, the burning rate would tend tobe stable.(5) After90days of storage, the second volume of delay composition had changed, andthat the burning rate decreased. Compared with the initial state, the burning rate reduced by13.64%, almost every10days on average reduced by1.62%.