[Back]


Publications in Scientific Journals:

S. Fricke, A. Friedberger, H. Seidel, U. Schmid:
"High temperature measurement set-up for the electro-mechanical characterization of robust thin film systems";
Measurement Science & Technology, 25 (2014), 0150071 - 0150076.



English abstract:
Due to economic and environmental requirements there is a strong need both to increase the
efficiency and to monitor the actual status of gas turbines, rocket engines and deep drilling
systems. For these applications, micromachined pressure sensors based on a robust substrate
material (e.g. sapphire) as well as strain gauges made of platinum for long-term stable
operation are regarded as most promising to withstand harsh environments such as high
temperature levels, aggressive media and/or high pressure loads. For pre-evaluation purposes,
a novel, custom-built measurement set-up is presented allowing the determination of
electro-mechanical thin film properties up to 850 ◦C. Key components of the measurement
set-up are the one-sided clamped beam made of Al2O3 ceramics which is deflected by a quartz
rod and a high precision encoder-controlled dc motor to drive the quartz rod. The specific
arrangement of the infrared halogen heaters in combination with the gold coated quartz half
shells ensures a high degree of temperature homogeneity along the beam axis. When exposed
to tensile as well as compressive load conditions, the corresponding gauge factor values of
1 μm thick platinum thin films show a good comparison at room temperature and in the
temperature range from 600 up to 850 ◦C where the effects originating from grain boundaries
or from the film surfaces are negligible. Between 150 and 600 ◦C, however, a strong deviation
in the gauge factor determination depending on the mechanical load condition is observed,
which is attributed to the gliding of adjacent grains.

German abstract:
Due to economic and environmental requirements there is a strong need both to increase the
efficiency and to monitor the actual status of gas turbines, rocket engines and deep drilling
systems. For these applications, micromachined pressure sensors based on a robust substrate
material (e.g. sapphire) as well as strain gauges made of platinum for long-term stable
operation are regarded as most promising to withstand harsh environments such as high
temperature levels, aggressive media and/or high pressure loads. For pre-evaluation purposes,
a novel, custom-built measurement set-up is presented allowing the determination of
electro-mechanical thin film properties up to 850 ◦C. Key components of the measurement
set-up are the one-sided clamped beam made of Al2O3 ceramics which is deflected by a quartz
rod and a high precision encoder-controlled dc motor to drive the quartz rod. The specific
arrangement of the infrared halogen heaters in combination with the gold coated quartz half
shells ensures a high degree of temperature homogeneity along the beam axis. When exposed
to tensile as well as compressive load conditions, the corresponding gauge factor values of
1 μm thick platinum thin films show a good comparison at room temperature and in the
temperature range from 600 up to 850 ◦C where the effects originating from grain boundaries
or from the film surfaces are negligible. Between 150 and 600 ◦C, however, a strong deviation
in the gauge factor determination depending on the mechanical load condition is observed,
which is attributed to the gliding of adjacent grains.

Keywords:
gauge factor measurement set-up, high temperatures, platinum, robust thin film systems, pressure sensors, harsh environment


"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)
http://dx.doi.org/10.1088/0957-0233/25/1/015007



Related Projects:
Project Head Ulrich Schmid:
Mikrosystemtechnik Projektkonto Schmid


Created from the Publication Database of the Vienna University of Technology.