Thin film thermocouples for internal combustion engines
The feasibility of fabricating thin film thermocouples on internal combustion engine hardware was investigated. The goal was to find a procedure that would be useful for the measurement of the surface metal temperature of valves, valve seats, combustion chamber surfaces, cylinder walls, and piston heads during engine operation. The approach pursued was to coat the engine hardware material with an aluminum-containing, oxidation-resistant ferrous alloy (FeCrAlY) which forms a thermal oxide layer with good electrical resistance. This thermal oxide was coated with a thin layer of reactively sputtered aluminum oxide and sputtered thin film type S thermocouple legs of platinum and platinum plus rhodium. This project was used to investigate the materials problems related to obtaining good adhesion in the metal/metal--oxide/oxide/metal laminate and the electrical insulating properties of the oxide. Thermal oxidation, reactive sputtering of Al/sub 2/O/sub 3/, and platinum alloy sputtering were investigated using optical microscopy, x-ray photoemission spectroscopy (XPS), laminar adhesion testing, and the evaluation of high temperature electrical properties. A successful method for fabricating thin film thermocouples on internal combustion engine materials was developed. Adherent, electrically insulating aluminum oxide with a type S thermocouple was produced on a 10 cm long stainless steel bar. The fabrication techniques and results of tests run on that bar as well as on numerous small test coupons are presented.
- Research Organization:
- Center for Chemical Engineering, National Bureau of Standards, Gaithersburg, Maryland 20899
- OSTI ID:
- 7241799
- Journal Information:
- J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 4:6; ISSN JVTAD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
330101* -- Internal Combustion Engines-- Spark-Ignition
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CHROMIUM ALLOYS
DESIGN
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON SPECTROSCOPY
ELEMENTS
EMISSION
ENGINES
FABRICATION
FEASIBILITY STUDIES
FILMS
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
IRON ALLOYS
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
MICROSCOPY
OPTICAL MICROSCOPY
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
PHOTOEMISSION
PHYSICAL PROPERTIES
PLATINUM
PLATINUM METALS
RHODIUM
SECONDARY EMISSION
SPECTROSCOPY
THERMOCOUPLES
THIN FILMS
TRANSITION ELEMENTS
YTTRIUM ALLOYS