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Title: Process for fabricating ZnO-based varistors

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.

Inventors:
 [1]
  1. (Oak Ridge, TN)
Issue Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN
OSTI Identifier:
865403
Patent Number(s):
4510112
Assignee:
United States of America as represented by United States (Washington, DC) ORNL
DOE Contract Number:  
W-7405-ENG-26
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
process; fabricating; zno-based; varistors; producing; incorporating; metal; oxide; dopant; form; comprises; providing; varistor; powder; mix; colloidal; particles; zno; metal-oxide; dopants; including; hot-pressed; compact; temperatures; below; 850; degree; conditions; effecting; reduction; sub-stoichiometric; promotes; densification; restricting; liquid; formation; grain; growth; heated; restoring; zinc; stoichiometric; composition; improving; properties; produces; fine-grain; characterized; breakdown; voltage; average; individual; boundary; colloidal particles; temperatures below; comprises providing; breakdown voltage; zinc oxide; metal oxide; process produces; liquid form; grain growth; grain boundary; zno-based varistors; stoichiometric composition; /264/338/

Citation Formats

Lauf, Robert J. Process for fabricating ZnO-based varistors. United States: N. p., 1985. Web.
Lauf, Robert J. Process for fabricating ZnO-based varistors. United States.
Lauf, Robert J. Tue . "Process for fabricating ZnO-based varistors". United States. https://www.osti.gov/servlets/purl/865403.
@article{osti_865403,
title = {Process for fabricating ZnO-based varistors},
author = {Lauf, Robert J.},
abstractNote = {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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1985},
month = {1}
}

Patent:

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