Abstract:
With SnO
2 powder, CuO powder, Nb
2O
5 powder and Cr
2O
3 powder as raw materials,(98.95-
x)SnO
2-1CuO-0.05Nb
2O
5-
xCr
2O
3(
x=0, 0.01, 0.02, 0.03, 0.05, mole fraction/%)varistor was prepared by powder metallurgy technique. The effect of Cr
2O
3 doping amount on the microstructure and electrical properties of the varistor was studied. The results show that with the increase of Cr
2O
3 doping amount, the relative density, shrinkage rate and average grain size of sintering samples first increased and then decreased. When the Cr
2O
3 mole fraction was 0.02%, the relative density and shrinkage rate of sintering sample were both the highest. When the Cr
2O
3 mole fraction was 0.01%, the grain size was the largest and the particle size distribution was the most uniform. With the increase of Cr
2O
3 doping amount, the voltage gradient of SnO
2 varistor increased, the leakage current density decreased first and then increased, and the nonlinear coefficient increased first and then decreased. When the mole fraction of Cr
2O
3 was 0.02%, the leakage current density was the smallest, the nonlinear coefficient was the largest, and the voltage gradient was high, indicating the best comprehensive electrical performance.