| Research status, basic theories and influencing factors about delay composition were mainly introduced in this paper. Using moulds by self-designed, the photoelectric test methond was used to test the effects of delay elements with different diameters on delay of sillicon delay composition. And Barium chromate was selected as auxiliary oxidant to prepare high period millisecond delay composition. At the same time, to understand the possible chemical reactions of this delay composition, combustion products of silicon delay composition doped with barium chromate were analyzed by X-ray diffraction. In orde to further slow down the burning rate of silicon delay composition, based on silicon reagent loaded with barium chromate, three kinds of slow burner were added to investigate the their effects on delay time of millisecond delay composition. And the conclusions were drawn as follows:(1)With the number of the drawing times increasing, the column diameter decreases gradually, when the diameter of the delay element is 3.00 mm, the burning rate is the fastest. Meanwhile, the combustion is the most stable.(2) For barium chromate as the auxiliary oxidant, with increasing the content of barium chromate, the average burning rate gradually slowed down. And after decomposition of barium chromate, the products appear to continue to be oxidized.(3) After adding slow burners, cryolite and selenium, into the delay composition, the longest delay time can be achieved 2 seconds. Besides, the precision of delay has been improved. However, it can not be guaranteed that, when the content of the fuel is too low, adding composite slow burners will reduce combustion stability(4) Using calcium fluoride as slow burner, the delay time have greatly increased. And with the increasement of calcium fluoride content, the burning rate can reduce to be 0.61 cms-1. The optimum content is ranging from 5% to 8%. Additionally, the high combustible content is conducive to composition storage. |
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