PRODUCTION OF ZINC OXIDE SINTERED COMPACT

摘要

PURPOSE: To uniformly carry out the grain growth and obtain a zinc oxide sintered compact useful for providing a varistor of good quality at a low cost by adopting specific heat-up conditions in baking a zinc oxide varistor composition having a specified composition. CONSTITUTION: This method for producing a zinc oxide sintered compact is to adopt the following conditions in sintering a zinc oxide varistor composition containing at least >=78mol% zinc oxide, 0.1-2mol% bismuth oxide, 0.1-2mol% TiO2 and 0.01-0.5mol% antimony oxide (expressed in terms of Sb2 O3 ). That is, the temperature is increased at 175-500/hr heat-up rate within the baking temperature range of 650-950 deg.C which is an initial phase temperature range of a zinc oxide spinel solid solution and 30-500 deg.C/hr heat-up rate within the temperature range of 950-1300 deg.C. The binder is preferably previously removed at 350-650 deg.C temperature in an oxidizing atmosphere before normal sintering within the initial phase temperature range and the normal sintering is then preferably carried out by replacing the atmosphere or in another furnace.