Evaluation of new metal-insulator-semiconductor varistor: Final report
A new, composite varistor material containing a metal, an insulator, and a semiconductor was evaluated. Although other constituents can be substituted, the materials that were investigated contained varying proportions of nickel metal, silicon dioxide, and silicon carbide in a silicon rubber binder. The material has rubber-like flexibility and is easily formed into complex shapes. A higher leakage resistivity (/approximately/10/sup 12/ ohm cm) and greater nonlinearity (/approximately/10) than for commercial silicon carbide varistors will permit the material to be used as a gapless surge suppressor. The breakdown voltage (1 kV/cm-10 kV/cm) and other properties of the material vary with composition. High-current capability (>200 A/cm/sup 2/) and good energy absorption (>40 J/cm/sup 3/) are found. The material exhibits a low-temperature coefficient (/approximately/4 x 10/sup -3//K) and a low dielectric constant (/approximately/10) with no observed loss peak. These dielectric properties are suited to high-frequency applications, such as antenna protection. The material has a response time (<1 ns) that should provide some protection against fast pulses generated by nuclear and directed-beam weapons. At this stage, the physics of the material are mostly conjecture, but the electrical conduction is almost certainly controlled by grain-boundary barriers. However, the conduction is not thermally activated, and it probably has a percolative character. The material will not replace zinc oxide varistors at this time, but it will find specialized applications in which its flexibility, formability, and frequency response are advantageous. 8 refs., 12 figs., 2 tabs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 7189648
- Report Number(s):
- ORNL/TM-10886; ON: DE88015708
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
Similar Records
Development of a new type of nonlinear resistance valve block for surge arresters. Final report
Electrical properties of medium field, chem-prep varistors. [ZnO doped with Co, Mn, or Al]
Related Subjects
36 MATERIALS SCIENCE
SEMICONDUCTOR RESISTORS
DIELECTRIC PROPERTIES
ELECTRICAL PROPERTIES
NICKEL
PROGRESS REPORT
SILICON CARBIDES
SILICON OXIDES
TESTING
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
DOCUMENT TYPES
ELECTRICAL EQUIPMENT
ELEMENTS
EQUIPMENT
METALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RESISTORS
SEMICONDUCTOR DEVICES
SILICON COMPOUNDS
TRANSITION ELEMENTS
420800* - Engineering- Electronic Circuits & Devices- (-1989)
360104 - Metals & Alloys- Physical Properties
360603 - Materials- Properties