| 摘要 |
<p>PURPOSE:To produce a zinc oxide varistor having an anisotropic structure in the c-axis direction by molding acicular zinc oxide particles crystallized in the c-axis direction so as to orient the particles in the c-axis direction and by sintering the molded body. CONSTITUTION:Zinc oxide particles of about several mum average particle size are hydrothermally treated under proper conditions to grow the crystals in the c-axis direction. About 0.1-0.8mol. several kinds of oxides such as oxides of Bi, Mn, Co and Sb are added to the resulting acicular zinc oxide particles 1 and they are mixed and press-molded so as to orient the particles 1 in the c-axis direction. The molded body is sintered as usual and electrodes are fitted to both ends of the sintered body to produce a zinc oxide varistor 10 having a structure in which acicular zinc oxide particles 1 are enclosed with a grain boundary layer 2 of the added oxides.</p> |
