TUNGSTEN/TUNGSTEN-RHENIUM THERMOCOUPLES IN A CARBON ATMOSPHERE,
Abstract
In an effort to extend the useful thermocouple range to 2500 C and beyond, investigations have been conducted in the use of refractory metal wires as thermocouple legs. To determine the feasibility of employing tungsten and tungsten-rhenium alloys in selected environments, both exposed bead and preformed tantalum-sheathed thermocouples were studied. A series of thermal stability tests have been conducted at temperatures up to 1400 C, as well as a very high temperature test at 2400 C. Both W/W 26% Re and W 5% Re/W 26% Re thermocouples were tested in a reduced pressure carbon-argon atmosphere. A comparison was made of the electromotive force obtained and that predicted by the standard published data. Analysis of the findings indicates that thermal cycling can effect a 2.5% increase in emf output; furthermore, the use of thoria insulators limits the maximum useful temperature of the thermocouples to 2300 C. The effectiveness of the tantalum sheath is discussed, as well as the comparative capabilities of the preformed and exposed bead thermocouples of both the W/W 26% Re and W 5% Re/W 26% Re types. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1964
- Accession Number
- AD0606565
Entities
People
- Albert P. Levitt
- Raymond L. Farrow
Organizations
- United States Army Research Laboratory