Abstract
The present paper describes the effect of firing atmosphere and additive Cu2O on the non-linearity of SiC varistors; the non-linearity is expressed by a equation, I=(V/C)α. The SiC varistor fired in air has a low resistance and shows a high α which remarkably decreases with an increase in the current flowing through the SiC varistor while the SiC varistor fired in H2 and N2 has a high resistance and shows a low α which slightly decreases with the current. Partial pressure of oxygen in N2 has a strong effect on the resistance of SiC varistor; the lowest resistance is obtained with about 5mmHg of oxygen partial pressure. When SiC varistor incorporated with a minor amount of Cu2O is fired in N2 or H2, it produces a low resistance and a high α which is constant with a current flowing through the SiC varistor, An effect of additive Cu2O is discussed in view of the X-ray microanalyser.
