Phase stability analysis of shocked ammonium dihydrogen phosphate by X-ray and Raman scattering studies

Abstract

Impact of shock waves on non-linear optical materials bring about a lot of unknown behaviors of materials and such kinds of shock wave recovery experiments are highly required for the better understanding of material-property relationship. In the present context, we have performed experiments on the impact of structural properties of ammonium dihydrogen phosphate (ADP) samples under shock wave loaded conditions and the results of the test samples have been evaluated by X-ray diffraction (XRD), Raman spectroscopy, diffused reflectance spectroscopy (DRS) and field emission scanning electron microscopic (FESEM) technique. Interestingly, prismatic face of ADP shows loss of degree of crystallinity whereas pyramidal face shows enhancement of crystalline nature with respect to number of shock pulses due to shock wave induced dynamic re-crystallization. Hence, the present problem is worthy enough to unearth and understand the anisotropic nature of the ADP crystal and their structural modifications at shock wave loaded conditions.

Experimental Evidence of Acoustic Shock Wave-Induced Dynamic Recrystallization: A Case Study on Ammonium Sulfate

“…As observed, the enhancement of the intensity ratio, as shown in Figure c,d, is linearly increased while increasing the number of shock pulses, and the obtained results clearly show that the degree of recrystallization increases linearly when increasing the number of shock pulses. The observed results are found to be in good agreement with the attachment energy theory of crystallization − and the previously obtained shock wave-induced results of structural properties. , To draw a parallel line, shocked samples of ammonium dihydrogen phosphate (ADP) and potassium dihydrogen phosphate (KDP) polycrystalline are considered for a better comparative analysis of the observed results. Note that the ADP and KDP crystals have two dominant planes that are (200) and (101), respectively, with the respective growth rates of 2.21 and 2.25.…”

“…Note that the ADP and KDP crystals have two dominant planes that are (200) and (101), respectively, with the respective growth rates of 2.21 and 2.25. In addition, the attachment energies of the (200) and (101) planes for the KDP crystal are 36 and 101 kcal/mol, respectively, and hence, under shocked conditions, the (101) peak intensity increases with respect to the number of shock pulses; similar results have been observed for the ADP crystal under shocked conditions, and the values of the intensity ratio for the (200)/(101) plane are presented in Figure d with respect to the number of shock pulses …”

“…For a clear understanding of the enhancement of the optical transmittance of AS samples under shocked conditions, the optical transmittance percentage is measured at three different wavelength regions such as 400, 450, and 500 nm; the measured values of the optical transmittance are displayed in Figure b with respect to the number of shock pulses. Figure b clearly demonstrates that the linear enhancement of the optical transmittance with respect to the number of shock pulses is because of the formation of a high degree of crystalline AS samples under shocked conditions, and similar kinds of results have been found under shocked conditions …”

“…The observed results are found to be in good agreement with the attachment energy theory of crystallization 24−26 and the previously obtained shock wave-induced results of structural properties. 27,28 To draw a parallel line, shocked samples of ammonium dihydrogen phosphate (ADP) and potassium dihydrogen phosphate (KDP) polycrystalline are considered for a better comparative analysis of the observed results. Note that the ADP and KDP crystals have two dominant planes that are (200) and (101), respectively, with the respective growth rates of 2.21 and 2.25.…”

“…Figure 5b clearly demonstrates that the linear enhancement of the optical transmittance with respect to the number of shock pulses is because of the formation of a high degree of crystalline AS samples under shocked conditions, and similar kinds of results have been found under shocked conditions. 27 FE-SEM Results. To provide considerably convincing evidence for the shock wave-induced dynamic recrystallization process occurring within milliseconds in the AS sample, FE-SEM analysis has been performed such that the obtained micrographs are portrayed in Figures 6 and 7.…”