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Durability Evaluation of a Thin Film Sensor System With Enhanced Lead Wire Attachments on SiC/SiC Ceramic Matrix CompositesAn advanced thin film sensor system instrumented on silicon carbide (SiC) fiber reinforced SiC matrix ceramic matrix composites (SiC/SiC CMCs), was evaluated in a Mach 0.3 burner rig in order to determine its durability to monitor material/component surface temperature in harsh environments. The sensor system included thermocouples in a thin film form (5 microns thick), fine lead wires (75 microns diameter), and the bonds between these wires and the thin films. Other critical components of the overall system were the heavy, swaged lead wire cable (500 microns diameter) that contained the fine lead wires and was connected to the temperature readout, and ceramic attachments which were bonded onto the CMCs for the purpose of securing the lead wire cables, The newly developed ceramic attachment features a combination of hoops made of monolithic SiC or SiC/SiC CMC (which are joined to the test article) and high temperature ceramic cement. Two instrumented CMC panels were tested in a burner rig for a total of 40 cycles to 1150 C (2100 F). A cycle consisted of rapid heating to 1150 C (2100 F), a 5 minute hold at 1150 C (2100 F), and then cooling down to room temperature in 2 minutes. The thin film sensor systems provided repeatable temperature measurements for a maximum of 25 thermal cycles. Two of the monolithic SiC hoops debonded during the sensor fabrication process and two of the SiC/SiC CMC hoops failed during testing. The hoops filled with ceramic cement, however, showed no sign of detachment after 40 thermal cycle test. The primary failure mechanism of this sensor system was the loss of the fine lead wire-to-thin film connection, which either due to detachment of the fine lead wires from the thin film thermocouples or breakage of the fine wire.
Document ID
20000034009
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Lei, Jih-Fen (NASA Glenn Research Center Cleveland, OH United States)
Kiser, J. Douglas (NASA Glenn Research Center Cleveland, OH United States)
Singh, Mrityunjay (DYNACS Engineering Co., Inc. Brook Park, OH United States)
Cuy, Mike (DYNACS Engineering Co., Inc. Brook Park, OH United States)
Blaha, Charles A. (Akima Corp. Brook Park, OH United States)
Androjna, Drago (Akima Corp. Brook Park, OH United States)
Date Acquired
September 7, 2013
Publication Date
March 1, 2000
Subject Category
Instrumentation And Photography
Report/Patent Number
NAS 1.15:209917
E-12154
NASA/TM-2000-209917
Funding Number(s)
PROJECT: RTOP 523-31-13
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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