Use of indexed sensitivity factors in the analysis of nickel and iron based alloys: study of the decalibration of sheathed Chromel/Alumel thermocouples
Sheathed Chromel versus Alumel thermocouples decalibrate when exposed to temperatures in excess of 1100/sup 0/C. Thermocouples sheathed in Inconel-600 and type 304 stainless steel were studied in this work. Quantified SIMS data showed that the observed decalibrations were due to significant alterations that took place in the Chromel and Alumel thermoelements. The amount of alteration was different for each thermocouple and was influenced by the particular sheath material used in the thermocouple construction. Relative sensitivity factors, indexed by a matrix ion species ratio, were used to quantify SIMS data for three nickel-based alloys, Chromel, Alumel, and Inconel-600, and an iron-based alloy, type 304 stainless steel. Oxygen pressure >2 x 10/sup -6/ torr in the sputtering region gave enhanced sensitivity and superior quantitative results as compared to data obtained at instrumental residual pressure.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6426626
- Report Number(s):
- CONF-781076-1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400100* -- Analytical & Separations Chemistry
440300 -- Miscellaneous Instruments-- (-1989)
47 OTHER INSTRUMENTATION
ALLOYS
ALUMEL
ALUMINIUM ALLOYS
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CHROMEL
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
CORROSION RESISTANT ALLOYS
ERRORS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
INCONEL 600
INCONEL ALLOYS
ION MICROPROBE ANALYSIS
IRON ADDITIONS
IRON ALLOYS
IRON BASE ALLOYS
MANGANESE ALLOYS
MASS SPECTROSCOPY
MATERIALS
MEASURING INSTRUMENTS
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ALLOYS
NONDESTRUCTIVE ANALYSIS
SENSITIVITY
SILICON COMPOUNDS
SPECTROSCOPY
STAINLESS STEEL-304
STAINLESS STEELS
STEELS
THERMOCOUPLES
VERY HIGH TEMPERATURE