VARISTOR AND ITS MANUFACTURING PROCESS Russian patent published in 1998 - IPC

FIELD: electrical engineering. SUBSTANCE: varistor built on the basis of zinc oxide has glass-coated side surface of following composition, mass percent: PbO - 40-55; ZnO - 10-20; B₂O₃ - 15.5-21.0; Si O₂ - 11-17; Al₂O₃ - 0.5- 3.0; Al₂O₃ - 0.3-0.5; at least one oxide of groups Ti O₂ and Zr O₂ - 2-3; and at least one oxide of groups SrO and Bao - 0.5-5.0. Varistor glass layer contains, in addition, Cz₂O₃ , Mn₂O₃ , CoO - 0.05-0.5 mm of each. Varistor manufacturing process includes production of varistor blank by baking zinc oxide based mixture, coating side surface of blank with mixture of crystal glass powder and organic resin followed by annealing. Prior to coating side surface, slip is prepared from glass frit with grain size smaller than 25 mcm and solution of organic solvents, such as ethyl alcohol, as well as surface-active materials, such as polyethylene polyamine, slip is applied to side surface while subjecting it to mechanical actions, for example, by shaking and stirring. EFFECT: improved reliability of varistor. 2 cl, 1 dwg, 2 tbl