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Science and Technology of Energetic Materials

Vol.76, No.4 (2015)

Research paper

[ISEM2014]
Catalytic mechanism in combustion of propellant with ammonium nitrate
Larisa A. Demidova, Ye Z. Htwe, and Anatoli P. Denisjuk
p.87-91

Abstract

To clarify the catalytic mechanism in combustion of propellant with high ammonium nitrate (AN) contents the temperature distribution in combustion waves of catalyzed propellant with 70% AN at 1.2 and 2.1 MPa pressures was studied by the aid of tungsten-rhenium alloy micro-thermocouples (thickness ~5 μm). In addition, the structure and composition of combustion surface of quenched samples at 2 MPa pressure were also analyzed by the aid of electron microscope and x-ray microprobe analyzer (XMA). It was shown that by the aid of combined catalyst, consisting of 3% nickel salicylate, 3% potassium dichromate and 1.5% soot, combustion rate of base propellant with 70% AN can be raised up to 7 times at low pressure region with desirable decrease in pressure exponent ν (from 0.88 to 0.43). It was established that a carbonaceous skeleton layer with large accumulation of metallic catalyst agglomerates is formed on combustion surface of catalyzed propellant with AN, resulting the significant increase in conductive heat flow (qλ) from gas phase to condense phase. According to the result of heat balance of condense phase, qλ plays the leading role in propagation of combustion process at 2.1 MPa pressure. It was also established that the decomposition rate constant of catalyzed AN in condense phase is ~16 times higher than that of pure AN.

Keywords

ammonium nitrate, catalyst, thermocouple, electron microscope, x-ray microprobe analyzer

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