High performance zinc-oxide varistors mfr. - by impregnating parts after firing binder with antimony contg. soln., drying and sintering the part

摘要

A ceramic mixt. is formed which contains at least ZnO, additives and an organic binder and compressed into the required cylindrical shape, the binder is removed by firing, a soln. of SbCl3 in water-free ethanol, pref. 5-10 wt.%, is applied to the cylindrical surface, if required this application is repeated several times, the part is sintered and electrodes are formed on the end surfaces. USE/ADVANTAGE - The penetration of the Sb is deeper than with current tecniques and the concn. can be easily adjusted by adjustment of the concn. of SbCl3 in the soln. or the number of applications of the soln. to the cylinder. The effect is to give a more controllable resistance increase at the edges of the varistor, resulting in fewer high current flashover channels and so a higher power dissipation capacity.