Accession Number:

AD0606565

Title:

TUNGSTEN/TUNGSTEN-RHENIUM THERMOCOUPLES IN A CARBON ATMOSPHERE,

Descriptive Note:

Corporate Author:

ARMY MATERIALS RESEARCH AGENCY WATERTOWN MASS

Personal Author(s):

Report Date:

1964-07-01

Pagination or Media Count:

36.0

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 WW 26 Re and W 5 ReW 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 WW 26 Re and W 5 ReW 26 Re types. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE