@article{Wang2026, 
author = {Qi Wang and Yan Hu and Xuetong Zhao and Shenglin Kang and Jianglin Wang and Yuchen Li and Jing Guo and Gang Liu and Hansheng Cai and Lulu Ren and Lijun Yang and Ruijin Liao},
title = {Regional microstructural and electrical variations in large-sized ZnO varistor ceramics processed by cold sintering assistance},
year = {2026},
journal = {Journal of Advanced Ceramics},
keywords = {microstructure, cold sintering, ZnO-based varistor ceramics, regional heterogeneity, breakdown field},
url = {https://www.sciopen.com/article/10.26599/JAC.2026.9221333},
doi = {10.26599/JAC.2026.9221333},
abstract = {The cold sintering process (CSP) is recognized as an emerging low-temperature densification strategy that provides a scalable and energy-efficient route for producing advanced ceramics and composite materials. However, its application has thus far been largely confined to small samples (diameter <15 mm), leaving the behavior of large-sized electronic ceramics scarcely explored. Here, a multidoped ZnO-based varistor ceramic with a diameter of 40 mm was employed to investigate the regional heterogeneity induced by cold sintering and subsequent annealing. The synergistic effects of radial pressure attenuation, liquid-phase migration, Marangoni convection, and pore evacuation accelerated densification at the edges, leading to an intensified dissolution–precipitation process. Consequently, the edge region exhibited higher densification (relative density (ρr) = 94.3%), smaller pore volume (VP = 0.215 cm3·g−1), and larger grains (average grain size (Gaver) = 233 nm) compared with the center part (ρr = 91.6%, VP = 0.385 cm3·g−1, and Gaver = 189 nm). Furthermore, the regional heterogeneity originating from the CSP extended into the annealing stage, as reflected by a reduced leakage current (JL = 0.3 μA·cm−2), enhanced nonlinearity (α = 66), and a high breakdown field (Eb = 1108 V·mm−1) at the edge region. The superior electrical performance is attributed to the larger interface state density (NS = 2.9×1015 m−2) and higher barrier height (φb = 1.92 eV). This work elucidates the regional effect of cold sintering and offers theoretical insight for its industrial application.}
}