Dilatometer studies of praseodymium doped ceria: Effect of synthesis methods on sintering behaviour

Abstract

Praseodymium-doped ceria (Ce<inf>0.9</inf>Pr<inf>0.1</inf>O<inf>2</inf>, PDC), as an electrolyte material for IT-SOFCs, is investigated with respect to the effect of synthesis method and a detailed analysis was carried out to understand the effect on crystallite size, morphology, specific surface area and sintering behaviour. The various synthesis routes such as microwave assisted co-precipitation method, room temperature co-precipitation method and EDTA-citrate complexing method was adopted for the synthesis of praseodymium doped ceria-based nano-materials. XRD pattern confirms the fluorite-type crystal structure of ceria and Raman spectroscopy analysis confirms the structure with the presence of oxygen vacancies. PDC synthesised by microwave assisted co-precipitation method using isopropyl alcohol as solvent exhibited better sintering activity, reduced the sintering temperature and promoted the densification rate when compared to other synthesis methods with uni-model shrinkage behaviour with shrinkage maxima at 765 °C. Based on two sintering models (CHR/Dorn method), the initial stage sintering mechanism was investigated in the present study and confirmed that the grain boundary diffusion (m = 2) as the dominant mechanism and the activation energy was found to be 116 kJ/mol (CHR model) and 176 kJ/mol (Dorn Method) for initial stages of sintering for PDC material synthesised by microwave assisted co-precipitation method using isopropyl alcohol as solvent. © 2019 Elsevier B.V.