Process for production of varistor material

A process for the production of a varistor material having a nonlinear index (c) of at least 20, which comprises adding a manganese compound to zinc oxide; heating the obtained mixture in the form of a powder in the atmosphere at 1050 to 1150°C; grinding the material to give a particle size of 150 mesh or below; molding the powder into a desired shape; and sintering the same at 1200 to 1350°C; is disclosed.