Influence of spark plasma sintering temperature on the microstructures, dielectric and I–V properties of CaCu3Ti4O12 ceramics

• Published in: Journal of alloys and compounds 2020-07, Vol.829, p.154595, Article 154595
• Main Authors: Li, T., Sun, Y., Dai, H.Y., Liu, D.W., Chen, J., Xue, R.Z., Chen, Z.Q.
• Format: Article
• Language: English
• Subjects: Alternating current; Barrier layers; CaCu3Ti4O12 ceramics; Ceramics; Copper; Dielectric loss; Dielectric properties; Dielectric property; Frequency ranges; Frequency stability; High temperature; Nonlinear behavior; Plasma sintering; Positron annihilation; Potential barriers; Sol-gel processes; Spark plasma sintering; Spectrum analysis
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.154595

CaCu3Ti4O12 (CCTO) ceramics were prepared by the sol–gel process and sintered by the spark plasma sintering (SPS) process at different temperatures. The SPS process temperature has an important effect on the microtopography of CCTO ceramics. The results of EDS and positron annihilation spectroscopy indicate that Cu2+ diffuses from the inside to the surface of grains during the sintering process at high temperature. The permittivity (εr) of CCTO ceramics at the corresponding frequencies increases with increasing SPS temperature. However, the frequency stability of εr over the frequency range 40–106 Hz wanes gradually. The CCTO ceramics sintered at 900°Cand 950 °C present very low dielectric loss values(about 0.02) near 10 kHz. The change in εr and tanδ for CCTO ceramics can be explained by the internal barrier layer capacitance (IBLC) model and AC (alternating current) impedance spectra. The results of I–V nonlinear characteristics for CCTO ceramics make clear that the potential barrier height has a positive effect on the value of nonlinear coefficient. •CCTO ceramics was prepared by Thermal Technology’s SPS (spark plasma sintering) method.•Positron annihilation lifetime spectra is used to investigate the Cu2+ distribution in CCTO cermics, which supports the results of EDS.•900 ℃ is considered as a suitable SPS process temperature to obtain perfect micromorphology for CCTO ceramics.