Advanced metal oxide varistor concepts. Final report

Technical Report · Sun Jul 01 00:00:00 EDT 1984

OSTI ID:6506142

Philipp, H R; Mahan, G D; Levinson, L M

Zinc oxide varistors are ZnO-based ceramic semiconductor devices with highly nonlinear current-voltage characteristics similar to back-to-back Zener diodes but with much greater current, voltage, and energy-handling capabilities. Zinc oxide varistors have proven useful in a variety of applications, particularly as high-quality voltage suppression devices for the protection of ac and dc electric power transmission systems against the effects of transient overvoltages due to switching surges and lightning strikes. In the work described in this report, we have chosen to study simple varistor systems that use Bi or Pr as the varistor-forming additive and Co or Mn as the varistor-performance ingredient. Commercial varistor materials generally use Bi as the varistor-forming ingredient, and the sintering process in such material probably proceeds in the liquid phase. Varistor materials that use Pr as the varistor-forming ingredient are also produced commercially. However, owing to the high melting point of Pr/sub 2/O/sub 3/ compared to Bi/sub 2/O/sub 3/, sintering in these materials probably takes place in the solid state. The performance ingredients Co and Mn are present in almost all commercial mixes. Co is an interesting choice because it is known to introduce a deep level into ZnO, giving such varistors a green color.

• Research Organization: General Electric Co., Schenectady, NY (USA). Research and Development Center
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6506142
• Report Number(s): ORNL/Sub-84-17457/1; ON: DE84016677
• Country of Publication: United States
• Language: English

Related Subjects

24 POWER TRANSMISSION AND DISTRIBUTION
OVERVOLTAGE
ELECTRICAL TRANSIENTS
SEMICONDUCTOR DIODES
VOLTAGE REGULATORS
ZINC OXIDES
SEMICONDUCTOR RESISTORS
CURRENTS
ELECTRIC POWER
ELECTRICAL EQUIPMENT
NONLINEAR PROBLEMS
SURGES
CHALCOGENIDES
EQUIPMENT
OXIDES
OXYGEN COMPOUNDS
POWER
RESISTORS
SEMICONDUCTOR DEVICES
TRANSIENTS
VOLTAGE DROP
ZINC COMPOUNDS
200300* - Electric Power Engineering- Power Transmission & Distribution- (-1989)