The objective of this research program is to improve high temperature piezoelectric aluminum nitride (AlN) sensor technology to make it useful for instrumentation and health monitoring of current and future electrical power generation equipment. The program will extend the temperature range of the sensor from approximately 700 C to above 1000 C, and ultrasonic coupling to objects at these temperatures will be investigated and tailored for use with the sensor. The chemical vapor deposition (CVD) AlN deposition process was successfully transferred from film production on tungsten carbide substrates to titanium alloy and silicon carbide (SiC) substrates. Further evaluation of the ...
continued below
Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.
Descriptive information to help identify this report.
Follow the links below to find similar items on the Digital Library.
Description
The objective of this research program is to improve high temperature piezoelectric aluminum nitride (AlN) sensor technology to make it useful for instrumentation and health monitoring of current and future electrical power generation equipment. The program will extend the temperature range of the sensor from approximately 700 C to above 1000 C, and ultrasonic coupling to objects at these temperatures will be investigated and tailored for use with the sensor. The chemical vapor deposition (CVD) AlN deposition process was successfully transferred from film production on tungsten carbide substrates to titanium alloy and silicon carbide (SiC) substrates. Further evaluation of the piezoelectric films on titanium caused it to be discarded as a candidate material due to an excessive thermal expansion coefficient mismatch, causing film failure upon reheating from room temperature. Deposition on SiC is proceeding well, with a highly conductive grade of silicon carbide required for practical use. Additional substrate materials, including refractory metals and conductive ceramics, have been considered but are generally not promising in light of the experience with titanium. Pulsed laser deposition (PLD) was investigated as an alternate means of creating the films as an alternative to CVD. A concurrent effort has focused on investigation of means of coupling ultrasound from the sensor into the test object at high temperature. A literature search combined with preliminary experimentation has resulted in the selection of two methods for coupling: low melting point glasses and metal foil- pressure couplant. The work in the next two years of the program will include continued improvement of the CVD deposition process, experimental testing of films and coupling at high temperatures, and a laboratory demonstration of the sensor in a simulated industrial application
This report is part of the following collection of related materials.
Office of Scientific & Technical Information Technical Reports
Reports, articles and other documents harvested from the Office of Scientific and Technical Information.
Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.
Sebastian, James.Elevated Temperature Sensors for On-Line Critical Equipment Health Monitoring,
report,
September 29, 2003;
United States.
(digital.library.unt.edu/ark:/67531/metadc881279/:
accessed April 25, 2018),
University of North Texas Libraries, Digital Library, digital.library.unt.edu;
crediting UNT Libraries Government Documents Department.