A study on phase transition of CsCl reversible arrow NaCl in CsCl, NH4Cl and NH4Br by simultaneous AE-DTA measurement

The phase transition of the CsCl reversible arrow NaCl type structure was followed in CsCl, NH4Cl and NH4Br powder samples by simultaneous AE-DTA measurement. Acoustic emission (AE) was detected during the transition, which arose from cracking and/or the transition itself. The cumulative counts of AE during the forward and backward transitions decreased with the number of repeated heating/cooling cycles, and finally became constant. The averaged power spectra of AE in three samples were found to be similar to each other and consist of low (50-400 kHz) and high frequency (above 500 kHz) components. The latter tended to decrease with a repeated number of the cycles.