Advanced metal oxide varistor concepts. Final report
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
Similar Records
Varistor-initiated arcs in lightning arrestor connectors
Processing and properties of ZnO-based varistors
Related Subjects
24 POWER TRANSMISSION AND DISTRIBUTION
CHALCOGENIDES
CURRENTS
ELECTRIC POWER
ELECTRICAL EQUIPMENT
ELECTRICAL TRANSIENTS
EQUIPMENT
NONLINEAR PROBLEMS
OVERVOLTAGE
OXIDES
OXYGEN COMPOUNDS
POWER
RESISTORS
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SEMICONDUCTOR RESISTORS
SURGES
TRANSIENTS
VOLTAGE DROP
VOLTAGE REGULATORS
ZINC COMPOUNDS
ZINC OXIDES