Annealing effects of high sensitive thin strain gauges consisting of nickel carbon nanocomposites

Hybrid laminates consisting of fiber-reinforced thermoplastic films and metallic thin sheets are successively replacing thermoset-based systems due to their obvious advantages of higher formability and the aptitude for mass production. In order to monitor the material under operating condition, hybrid laminates need to be equipped with smart sensor units. Therefore, the aim of the present work is to evaluate the temperature stability of the Ni-C thin film strain gauge sensors. The analyses of the deposited Ni-C films manufactured by means of a magnetron sputtering process were carried out by means of Raman spectroscopy and X-ray diffraction to investigate the phase development after a heat treatment at different temperatures and holding times. In addition, the four-terminal sensing was utilized to study the change of temperature coefficients of resistance after a single annealing treatment