Temperature-Compensated Strain Gauges Using Metal-Semiconductor Nanocomposites

Abstract

The goal of this work is to develop a strain gage system which incorporates the aforementioned characteristics. To develop a sensor with embedded temperature compensation, a nanocomposite thin film sensing element was designed and fabricated. These nanocomposite films were prepared by mixing refractory metals such as tungsten, nickel or palladium, having a large, positive temperature coefficient of resistance (TCR) with a semiconductor such indium tin oxide (ITO) having a large negative TCR. The resultant was an optimal mixture of the two components alloys with a minimal TCR over an extended temperature range. The focus of this study was to investigate the plausibility of a self-temperature compensated nanocomposite alloy for use as the static strain elements in a thin film strain gage at elevated temperatures. Nanocomposite films were sputter deposited on a thin, flexible YSZ ceramic membrane substrates to facilitate easy attachment to sample surfaces with minimal interference from the sensor platform so that the measured strain is due to the compliance of the material to which the strain gage was attached. The purpose of the study was not to produce an optimized strain gage with near zero TCR and large gage factor, but rather provide an approach or roadmap to develop nanocomposites for static strain gage applications where low TCR’s are required.