Pure ZrO2 powders were prepared by the sol-gel method from zirconium oxychloride. For hydrolysis and peptization aqua ammonia and nitric acid were used. The obtained hydrogel was converted to xerogel by aging in air at room temperature and subsequent drying at 373 K for 30 min. This initial xerogel was calcinated in air at different temperatures in the range from 873 to 1273 K for 30 min. Beta irradiated powder exhibit four thermoluminescence peaks with maxima at 340, 415, 470 and 540 K. To clarify the structure of the glow curves a thermal cleaning procedure was used. The initial rise method and deconvolution of the glow curves recorded after preheats were applied to determine the peaks kinetic parameters. All the peaks are well described by one set of the kinetic parameters. The kinetics orders are equal to 2.0, 1.4, 1.7, 1.3 and the activation energies are equal to 0.65, 0.78, 1.1, 1.2 for the increasing peak temperatures, respectively. The calcination temperature strongly influences the sensitivity of ZrO2. The dependences of the peak areas on the calcination temperature are fitted well with straight lines in the Arrhenius coordinates with the activation energy of 1.7 eV that can be related with migration of oxygen vacancies.
Bibliographical noteFunding Information:
We acknowledge financial support from SEP and Conacyt Grant Nos. 36521, 37641.
- Sol-gels (xerogels)