The Surface Structure and Properties Analysis of Ammonium Dinitramide Crystal

To investigate the surface properties of ammonium dinitramide (ADN) crystal, the number of anion and cation exposures, the roughness, the electronegativity, and the surface free energy of the important crystal planes were investigated by theoretical simulation. The relationship between above parameters and the hygroscopicity of crystal was discussed. The bond length distribution, the relationship between trigger bond density and surface free energy, the trigger bond energy and the mechanical sensitivity of different crystal planes were investigated. The results show that when the surfaces of ADN are negatively charged or neutral, the hygroscopicity is low, indicating that the exposed anions and cations on the crystal surfaces are related to the hygroscopicity. The more anions expose on the crystal surfaces, the stronger the hygroscopicity. It is found from the surface structure properties of crystal that the smoother the crystal surfaces, the lower the hygroscopicity, and the lower the mechanical sensitivity. The higher the surface free energy is, the stronger the hygroscopicity is. The smaller the trigger bond density of the crystal planes and the lower the trigger bond energy, and the greater the mechanical sensitivity. Among them, the (0 2 0) and (1 0 0) crystal planes have a higher degree of smoothness, less surface free energy, and greater trigger bond density and trigger bond energy, thus the hygroscopicity and mechanical sensitivity are low. © 2022, Editorial Board of Journal of Explosives & Propellants. All right reserved.