Conventional and Microwave‐Assisted Sintering of CaCu₃Ti₄O₁₂ Ceramics Obtained from Coprecipitated Powders

Abstract

CaCu 3 Ti 4 O 12 (CCTO) powders were prepared by coprecipitated method starting from CaCO 3 , Cu(NO 3 ) 2 , and Ti-butoxide. The exclusive presence of CCTO phase was confirmed by X-ray diffraction analyses after calcination at 850°C for 2 h. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) confirmed nanosized particles of CCTO phase. Samples were sintered in conventional and microwave oven at 1050°C, producing differences on particles and grain size, densification, microstructure, and dielectric properties of the ceramics. Energy dispersive X-ray spectroscopy (EDS) was performed in the grain and grain boundary to investigate the formation and composition of the secondary phase formed during sintering methods. It could be noted that the presence of this secondary phase interferes directly on dielectric constant and loss factor values.

Improved dielectric properties of Na1/2Y1/2Cu3Ti4O12 ceramics synthesized by ball-milling and reactive sintering

“…Several studies aimed to replace SSR by lower temperature fabrication process without scarifying the giant dielectric properties of the ceramic. One strategy is to use rapid sintering techniques such as spark plasma sintering (SPS) [11,17] and microwave sintering [18]. Another strategy is to use sol-gel process to prepare the precursor powder with nano-metric size which reduce the calcination and sintering temperature to prepare the dense ceramics [19].…”

Yttrium Copper Titanate as a Highly Efficient Electrocatalyst for Oxygen Reduction Reaction in Fuel Cells, Synthesized via Ultrafast Automatic Flame Technique

“…The main FT-IR absorption peaks were found at 576, 528, and 446 cm −1 , which were assigned to the absorption regions of the Ti ion ascribed to ν Ti−O (653–550 cm −1 ) and ν Ti−O−Ti (495–436 cm −1 ) as shown in Fig. 2(c) 30 . Therefore, the main resonance absorptions are in good agreement with those of a structurally similar CCTO perovskite 31 .…”

Deficient or excessive CuO‐TiO2 phase influence on dielectric properties of CaCu3Ti4O12 ceramics

“…Studies on the CuO stoichiometry by Fang et al revealed that CuO‐rich stoichiometric compositions exhibit exaggerated grain growth, confirming that this liquid phase assisted the sintering mechanism. This fact is consistent with the microstructural results obtained in CC X T Y O ceramics, where the liquid phase generated by both the stoichiometric excess of Cu and Ti and by the liquid phase derived from the decomposition of the CCTO phase had a noticeable influence in the microstructure consolidation.…”

“…It is clear that the sintering temperature is strongly dependent on the CC X T Y O composition and this parameter will also affect the dielectric properties of these ceramics. Supported by previous studies by Thomazini et al, all CC X T Y O ceramics were sintered at a single sintering temperature, which was above the highest temperature value recorded in the dilatometric analysis, thus, the temperature was fixed at 1050°C. Temperatures close to this are commonly reported in the literature for sintering CCTO ceramics, and many of them reaching long holding times; but with the synthesis method proposed in this study, the holding time used was 120 minutes.…”