DRIFT STUDIES ON CHROMEL-P-ALUMEL THERMOCOUPLES IN HELIUM ATMOSPHERES

Journal Article · Mon Jan 01 00:00:00 EST 1962 · Temp. Meas. Control Sci. Ind.

OSTI ID:4683027

Bennett, R L; Rainey, Jr, W T; McClain, W M

The use of Chromel-P-Alumel thermocouples under certain atmospheric conditions resulted in severe negative emf errors. These emf drifts were investigated in stagnant and flowing air and helium atmospheres with and without solid contaminants. Results indicated that the principai mechanism involved in the negative emf drift phenomenon was the selective oxidation of chromium in the 800-900 deg C region of the Chromel wire. Selective intergranular oxidation of the chromium occurred only in a limited temperature range and within rather critical limits of atmospheric oxidizing potential. (C.E.S.)

• Research Organization: Oak Ridge National Lab., Tenn.
• NSA Number: NSA-17-030829
• OSTI ID: 4683027
• Journal Information: Temp. Meas. Control Sci. Ind., Vol. Vol: 3: Pt. 2; Other Information: Orig. Receipt Date: 31-DEC-63
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

INSTRUMENTS AND INSTRUMENTATION
AIR
ALUMEL
ALUMINUM ALLOYS
CHROMEL
CHROMIUM ALLOYS
CONTAMINATION
ERRORS
HELIUM
HIGH TEMPERATURE
MANGANESE ALLOYS
NICKEL ALLOYS
OXIDATION
SILICIDES
THERMOCOUPLES