Effects of B₂O₃ Dopants on the Electrical Properties of Ta‐Doped SnO₂ Varistors

As a new core component of surge arresters, it is crucial for manganese dioxide varistors to solve the challenges of reducing the leakage current and lowering the residual voltage ratio. In this study, the electrical characteristics of tin dioxide varistors using B 2 O 3 as the acceptor dopant and Ta 2 O 5 as the donor dopant are investigated. Several tin dioxide based varistors doped with different amounts of B 2 O 3 are prepared and characterized by the researchers. X ray diffraction (XRD) is used to analyze the structural features of the samples and to observe the phases involved. It is found that the B 2 O 3 dopant provides oxygen vacancies, reduces the grain size, increases the barrier height, and decreases the residual pressure ratio. The Ta 2 O 5 dopant provides donor defects and free electrons needed to form the barrier. When balancing the concentrations of B 2 O 3 and Ta 2 O 5 , the optimum dopant concentrations is found to be 0.1 mol% of B and 0.05 mol% of Ta; these concentrations result in a leakage current of 0.25 μA cm −2 , a residual pressure ratio of 1.95, a nonlinear coefficient of 25, and a voltage gradient of 394 V mm −1 for the varistor.