Plastic and nonmetallic article shaping or treating: processes – Disparate treatment of article subsequent to working,... – Effecting temperature change
Patent
1983-01-21
1985-04-09
Parrish, John A.
Plastic and nonmetallic article shaping or treating: processes
Disparate treatment of article subsequent to working,...
Effecting temperature change
264332, 264345, H01B 108
Patent
active
045101124
ABSTRACT:
The invention is a process for producing ZnO-based varistors incorporating a metal oxide dopant. In one form, the invention comprises providing a varistor powder mix of colloidal particles of ZnO and metal-oxide dopants including Bi.sub.2 O.sub.3. The mix is hot-pressed to form a compact at temperatures below 850.degree. C. and under conditions effecting reduction of the ZnO to sub-stoichiometric oxide. This promotes densification while restricting liquid formation and grain growth. The compact then is heated under conditions restoring the zinc oxide to stoichiometric composition, thus improving the varistor properties of the compact. The process produces fine-grain varistors characterized by a high actual breakdown voltage and a high average breakdown voltage per individual grain boundary.
REFERENCES:
patent: 3955168 (1976-05-01), Levinson
patent: 4046847 (1977-09-01), Kresge
patent: 4052340 (1977-10-01), Eijnthoven
patent: 4165351 (1979-08-01), Moy
patent: 4180483 (1979-12-01), Ho
patent: 4219518 (1980-08-01), Philipp
patent: 4243622 (1981-01-01), Kresge
patent: 4338223 (1982-07-01), Yokomizo
patent: 4349496 (1982-09-01), Levinson
Snow, "Hot Press With Flat Plate Heaters and Its Application to the Fabrication of Large Varistor Slugs", Am. Cer. Soc. Bull., May 1980, pp. 550-551.
Snow, "Characterization of High Field Varistors in the System ZnO-CoO-PbO-Bi.sub.2 O.sub.3 ", Am. Cer. Soc. Bull., Jun. 1980, pp. 617-622.
Hamel Stephen D.
Lewis Fred O.
Parrish John A.
The United States of America as represented by the United States
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