Helium defectoscopy of cerium gadolinium ceramics [Ce.sub.08][Gd.sub.0.2][O.sub.1.9] with a submicrocrystalline structure in the impurity disorder region

• Published in: Physics of the solid state Vol. 55; no. 12; pp. 2537 - 2542
• Main Authors: Koromyslov, A.V, Zhiganov, A.N, Kovalenko, M.A, Kupryazhkin, A. Ya
• Format: Journal Article
• Language: English
• Published: Springer 01.12.2013
• Subjects: Analysis; Ceramic materials; Ceramics; Cerium; Electric properties; Electrical conductivity; Gadolinium; Toy industry
• ISSN: 1063-7834; 1090-6460
• DOI: 10.1134/S1063783413120159

The concentration of impurity anion vacancies formed upon the dissociation of gadolinium--vacancy complexes has been determined using helium defectoscopy of the cerium gadolinium ceramics [Ce.sub.08][Gd.sub.0.2][O.sub.1.9] with a submicrocrystalline structure in the temperature range T = 740-1123 K and at saturation pressures ranging from 0.05 to 15 MPa. It has been found that the energy of dissociation of gadoliniumvacancy complexes is [E.sup.D.sub.eff] = 0.26 ± 0.06 eV, and the energy of dissolution of helium in anion vacancies in the impurity disorder region is [E.sup.P] = -0.31 ± 0.09 eV. The proposed mechanism of dissolution has been confirmed by the investigation of the electrical conductivity of the cerium gadolinium--ceramics, as well as by the high-speed molecular dynamics simulation of the dissociation of gadolinium--vacancy complexes. It has been assumed that a decrease in the effective dissolution energy in comparison with the results of the previously performed low-temperature investigations is caused by the mutual repulsion of vacancies formed upon the dissociation of gadolinium--vacancy complexes in highly concentrated solutions of gadolinium in Ce[O.sub.2] with increasing temperature.