Study of the Hydrolytic Stability of Fine-Grained Ceramics Based on Y2.5Nd0.5Al5O12 Oxide with a Garnet Structure under Hydrothermal Conditions |
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| Authors: | Liudmila Alekseeva,Aleksey Nokhrin,Maksim Boldin,Eugeniy Lantsev,Artem Murashov,Albina Orlova,Vladimir Chuvil’ deev |
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| Affiliation: | Materials Science Department, Physico-Technical Research Institure, Lobachevsky State University of Nizhny Novgorod, 603022 Nizhny Novgorod, Russia; (M.B.); (E.L.); (A.M.); (A.O.); (V.C.) |
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| Abstract: | The hydrolytic stability of ceramics based on Y2.5Nd0.5Al5O12 oxide with a garnet structure obtained by the spark plasma sintering (SPS) method has been studied. The tests were carried out in distilled water under hydrothermal conditions in an autoclave and, for comparison, in a static mode at room temperature. The mechanism of leaching of Y and Nd from the ceramics was investigated. It has been shown that at “low” temperatures (25 and 100 °C), the destruction of pores occured, and the intensity of the leaching process was limited by the diffusion of ions from the inner part of the sample to the surface. At “high” test temperatures (200 and 300 °C), intense destruction of the ceramic grain boundaries was observed. It was assumed that the accelerated leaching of neodymium is due to the formation of grain-boundary segregations of Nd3+ in sintered ceramics. |
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| Keywords: | ceramic matrices immobilization of radioactive wastes garnet hydrolytic tests leaching mechanism |
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