ALKALI METAL RESISTANT WIRE
Abstract
A ceramic coated conductor system was developed that was unaffected by 172 hours exposure to K (potassium) vapor at 850 C. This system was Metco 201 Zirconia, plasma sprayed on nickel aluminide coated Nickel clad Silver AWG 8 (Sylvania) wire. This system, however, is not suitable for electrical operation at 850 C since the resistance of the zirconia coating drops to about 5 ohms at 600 C. Overcoating the zirconia with aluminum nitride by a vapor plating technique results in a resistance at 850 C in argon for the multicoat of 1.8 x 10 to the 4th power ohms. The aluminum nitride overcoated zirconia is unaffected by 172 hours exposure. A number of high purity insulators were found to be resistant to potassium vapor at 850 C. These were alumina, magnesia, and strontium zirconate. A primary problem with plasma spray coatings of these materials is loss of adhesion in the potassium vapor even when a nickel aluminide undercoat is used.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 15, 1964
- Accession Number
- AD0436294
Entities
People
- E. S. Bober
- R. E. Stapleton
- W. H. Snavely
Organizations
- Westinghouse Electric Corporation