TY - JOUR
T1 - Thermal-assisted cold sintering of ZnO varistor ceramics to realize high breakdown field
T2 - Roles of hydrated metal salts
AU - Kang, Shenglin
AU - Zhao, Xuetong
AU - Liao, Ruijin
AU - Wang, Qi
AU - Wang, Jianglin
AU - Li, Yuchen
AU - Liu, Gang
AU - Cai, Hansheng
AU - Guo, Jing
AU - Liu, Hongwen
AU - Yang, Jindong
AU - He, Jimou
AU - Gan, Yu
AU - Yin, Guilai
AU - Ren, Lulu
N1 - Publisher Copyright:
© 2026 Elsevier Ltd.
PY - 2026/12
Y1 - 2026/12
N2 - ZnO varistors with high breakdown strengths are essential for compact overvoltage protection devices, yet achieving high breakdown strength ( E b), high nonlinear coefficient ( α ), and low leakage current density ( J L) simultaneously remains challenging. Herein, ZnO varistor ceramics are fabricated via cold sintering process (CSP) using hydrated metal salts as both transient liquid media and dopants. This approach enables homogeneous dopant distribution along grain boundaries through a dehydration-assisted CSP at 350 °C, attaining a relative density of ∼94%. Subsequent annealing at 850 °C stabilizes grain boundaries and forms Bi-rich phases, constructing a high Schottky barrier of 3.36 eV. This combined approach of CSP and annealing suppresses ZnO grain growth (average grain size of 1.42 μm) and enhances densification to 98.8%, yielding an ultrahigh E b of 2777.52 V/mm, a high α of 147.53, and a low J L of 0.07 μA/cm2. This work provides an energy-efficient route to obtain superior ZnO varistor ceramics by cold sintering using hydrated metal salts, which was achieved by post-annealing.
AB - ZnO varistors with high breakdown strengths are essential for compact overvoltage protection devices, yet achieving high breakdown strength ( E b), high nonlinear coefficient ( α ), and low leakage current density ( J L) simultaneously remains challenging. Herein, ZnO varistor ceramics are fabricated via cold sintering process (CSP) using hydrated metal salts as both transient liquid media and dopants. This approach enables homogeneous dopant distribution along grain boundaries through a dehydration-assisted CSP at 350 °C, attaining a relative density of ∼94%. Subsequent annealing at 850 °C stabilizes grain boundaries and forms Bi-rich phases, constructing a high Schottky barrier of 3.36 eV. This combined approach of CSP and annealing suppresses ZnO grain growth (average grain size of 1.42 μm) and enhances densification to 98.8%, yielding an ultrahigh E b of 2777.52 V/mm, a high α of 147.53, and a low J L of 0.07 μA/cm2. This work provides an energy-efficient route to obtain superior ZnO varistor ceramics by cold sintering using hydrated metal salts, which was achieved by post-annealing.
KW - Annealing
KW - Cold sintering process
KW - Electrical performance
KW - Hydrated metal salts
KW - ZnO varistor ceramics
UR - https://www.scopus.com/pages/publications/105043426747
U2 - 10.1016/j.jeurceramsoc.2026.118641
DO - 10.1016/j.jeurceramsoc.2026.118641
M3 - 文章
AN - SCOPUS:105043426747
SN - 0955-2219
VL - 46
JO - Journal of the European Ceramic Society
JF - Journal of the European Ceramic Society
IS - 16
M1 - 118641
ER -