Science and Technology of Energetic Materials

Vol.79, No.1 (2018)

Research paper

Study of the hygroscopic deterioration of ammonium perchlorate/magnesium mixture
Yosuke Nishiwaki, Takehiro Matsunaga, and Mieko Kumasaki


A Study of hygroscopic deterioration is necessary because it can improve the safety and quality of pyrotechnics. For effective prevention of hygroscopic deterioration, this paper shows the deterioration mechanism of ammonium perchlorate (AP)/magnesium (Mg) mixture under the presence of moisture. The mixture has been used as Tenmetsuzai (Strobe composition in Japanese) and Mg has been known for its high hygroscopy. In this paper, the hygroscopic deterioration of strobe composition (AP/Mg mixture) was measured by aging test which we were developed, and the deterioration products were analyzed with X-ray diffraction system and scanning electron microscope. The experiments identified two deterioration products : magnesium hydroxide and magnesium perchlorate. The influence of storage temperature and humidity to the rate of deterioration were investigated, and it revealed that the relative humidity of atmosphere has a significant impact. AP/Mg showed drastic change at a point, and the point was considered to be Critical Relative Humidity. The rate equation which called Jander's equation was applied to the deterioration behavior obtained in the experiments, and its coefficients were obtained which enable to predict the degree of deterioration as function of time.

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pyrotechnics, ammonium perchlorate, magnesium, aging, humidity

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