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Attachment of Free Filament Thermocouples for Temperature Measurements on CMCCeramic Matrix Composites (CMC) are being developed for use as enabling materials for advanced aeropropulsion engine and high speed civil transport applications. The characterization and testing of these advanced materials in hostile, high-temperature environments require accurate measurement of the material temperatures. Commonly used wire Thermo-Couples (TC) can not be attached to this ceramic based material via conventional spot-welding techniques. Attachment of wire TC's with commercially available ceramic cements fail to provide sufficient adhesion at high temperatures. While advanced thin film TC technology provides minimally intrusive surface temperature measurement and has good adhesion on the CMC, its fabrication requires sophisticated and expensive facilities and is very time consuming. In addition, the durability of lead wire attachments to both thin film TC's and the substrate materials requires further improvement. This paper presents a newly developed attachment technique for installation of free filament wire TC's with a unique convoluted design on ceramic based materials such as CMC's. Three CMC's (SiC/SiC CMC and alumina/alumina CMC) instrumented with type IC, R or S wire TC's were tested in a Mach 0.3 burner rig. The CMC temperatures measured from these wire TC's were compared to that from the facility pyrometer and thin film TC's. There was no sign of TC delamination even after several hours exposure to 1200 C. The test results proved that this new technique can successfully attach wire TC's on CMC's and provide temperature data in hostile environments. The sensor fabrication process is less expensive and requires very little time compared to that of the thin film TC's. The same installation technique/process can also be applied to attach lead wires for thin film sensor systems.
Document ID
19970025591
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Lei, Jih-Fen (NASA Lewis Research Center Cleveland, OH United States)
Cuy, Michael D. (NASA Lewis Research Center Cleveland, OH United States)
Wnuk, Stephen P. (HITEC Products, Inc. Ayer, MA United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1997
Subject Category
Instrumentation And Photography
Report/Patent Number
E-10785
NAS 1.15:107488
NASA-TM-107488
Report Number: E-10785
Report Number: NAS 1.15:107488
Report Number: NASA-TM-107488
Accession Number
97N25087
Funding Number(s)
PROJECT: RTOP 537-04-22
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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