Inhibition effect of ammonium dihydrogen phosphate on the thermal decomposition characteristics and thermal sensitivity of ammonium nitrate

Abstract In order to analyze the inhibition effect of the additive on the thermal decomposition characteristics of ammonium nitrate (AN), thermal stability and thermal decomposition behavior of AN and its mixtures with various concentrations of ammonium dihydrogen phosphate (ADP) are systematically investigated by DSC-TG, DSC-TG-QMS and TG-FTIR. Breaking point value of the samples is obtained as an evaluation parameter for thermal safety. Experimental results show that the AN-ADP mixtures show higher onset decomposition temperatures, narrower reaction temperature region and lower enthalpy values than those of pure AN. The main evolved decomposition gases of AN are NH 3 , H 2 O, NO, N 2 O, NO 2 and HNO 3 , while the major gaseous products of the AN mixture with ADP are NH 3 , H 2 O, NO, N 2 O and NO 2 . Furthermore, the generation of NO and NO 2 is obviously postponed in the AN mixture. In addition, the breaking point value of AN is markedly improved by ADP. The decomposition mechanism of AN-ADP mixture is concluded and the inhibition mechanism of ADP is proposed. It is concluded that ADP is an effective inhibitor for AN and its thermal stability is effectively enhanced.