| 摘要 |
PURPOSE:To obtain better hygroscopic property along with less irregularity and better electric characteristics by making the grain boundary layer in a sinter partly amorphous, and regulating the containing ratios of the bismuth in the amorphous phase and that in a delta-Bi2O3 phase. CONSTITUTION:Mixed liquid mud is obtained by mixing zinc oxide raw material adjusted to a specified particle size, and a specified quantity of additives consisting of a bismuth oxide, a cobalt oxide, a silver oxide, etc., adjusted to a specified particle size. The liquid mud is supplied to a spray dryer and made into particles. Then, the obtained powder made into particles is shaped into a specified form and burned temporarily, and oxide paste is applied to the side of the temporary sinter to a thickness of 60-300mum. Next, this is regularly burned with a temperature rising or falling speed of 20-60 deg.C/hr at 1,000-1,300 deg.C for 3-7 hours. The bismuth quantity of each phase in the sinter satisfies conditions; (1) 0.10<=B/A<=0.40, (2) 0.05<=C/A<=0.30, wherein A: all the bismuth quantity in the sinter, B: the bismuth quantity in a delta-Bi2O3 crystal layer, and C: the bismuth quantity in an amorphous phase including bismuth. |
