English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

TiO2–Ta2O5–CaCO3 varistor ceramics were prepared by hot isostatic pressing (HIP) and annealed in oxygen and nitrogen, respectively. The nonlinear coefficient α, the breakdown voltage EB and the leakage current JL of samples were tested using a varistor dc parameter meter. The average barrier height ΦB of the unannealed samples and the samples annealed in oxygen and nitrogen was calculated. The microstructure of samples was analyzed by STEM-EDS, XRD and SEM. TiO2–Ta2O5– –CaCO3 varistor ceramics with uniform microstructure, fine grains and low porosity was obtained by HIP. By annealing, α increases, while EB and JL decrease. When annealing is performed in oxygen, the oxygen enrichment at the grain boundaries is also helpful to increase α and reduce JL. TiO2–Ta2O5–CaCO3 varistor ceramics with Ta2O5 and CaCO3 contents of 0.20 mol. % sintered at 1200 °C and annealed at 700 °C for 3 h in oxygen possesses best varistor performance with α = 11.2, EB = 22.6 V·mm and JL = 8.7 μA·cm.

PREPARATION AND CHARACTERIZATION OF TiO₂-Ta₂O5-CaCO₃ VARISTOR CERAMICS BY HOT ISOSTATIC PRESSING (HIP) AND POST-ANNEALING