Analysis of the sintering process in gadolinia-doped ceria by thermodilatometry and correlation with microstructure evolution
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The non-isothermal sintering process of cerium dioxide containing gadolinium sesquioxide powders within a wide range of specific surface area was investigated by dilatometry. Linear shrinkage data of powder compacts were recorded under several constant rates of heating. Dilatometry data were analyzed by two methodologies enabling to preview the relative density for any temperature/time profile, and determination of the apparent activation energy for sintering. Correlation of dilatometry results with microstructure evolution was also carried out. Remarkable differences in sintering powders with different specific surface areas were found. The apparent activation energy for sintering increases with decreasing specific surface area and, in most cases, it does not change significantly in the approximately 70–85% range of relative density.
KeywordsCeria Sintering Dilatometry Modeling Microstructure
The authors acknowledge FAPESP (2013/07296-2), CNPq (Proc. no. 304073/2014-8) and CNEN for financial supports, and the Laboratory of Electron Microscopy at IPEN for TEM observation. One of the authors (R.M.B.) acknowledges Capes for the scholarship.