کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
701947 | 1460811 | 2011 | 5 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Me-DLC films as material for highly sensitive temperature compensated strain gauges Me-DLC films as material for highly sensitive temperature compensated strain gauges](/preview/png/701947.png)
In technical applications strain gauges are widely used. Apart from conventional polymer foil based strain gauges that are glued to the work piece surface, sputtered strain gauges are already commercially used in special applications. Those sputter strain gauges are typically made of NiCr alloy and the sensor layer is as sensitive to strain as the ones used in the glued strain gauges with a gauge factor of 2, but neglecting problems of creeping and swelling of the involved polymer materials. Diamond-like carbon (DLC) films offer significantly higher strain sensitivity, but usually they are also very sensitive to temperature effects. Using metal doped diamond-like carbon (Me-DLC), higher strain sensitivity than conventional metal based systems, in combination with thermal compensation, is possible. The influence of different process parameters on the gauge factor and temperature coefficient of resistance (TCR) of DLC and Me-DLC films produced in industrial sputtering systems was investigated. Gauge factors up to 13 in combination with a high negative TCR in the range of a few thousand ppm/K were reached with sputtered DLC films. The substrate bias voltage in particular showed a strong influence on the resulting gauge factor of the films. For Me-DLC films different deposition methods (dc and rf sputtering) and various doping metals (Ag, Ni, Ti, and W) were investigated. Using dc sputtering of the Me-DLC films only Ni-DLC showed gauge factors slightly higher than 2. Furthermore, only for Ni-DLC zero crossing of the TCR was observed by variation of the metal content. Using rf excitation especially Ni-DLC films showed gauge factors exceeding values of 15 in combination with a TCR close to zero.
Research highlights
► Influence of deposition parameters on gauge factor and TCR for sputtered DLC films.
► Comparison of gauge factor and TCR for different Me-DLC films.
► Significant differences in gauge factors for dc and rf sputtered Ni-DLC films.
► TCR is independent of whether dc or rf sputtering was used for Ni-DLC.
► Discussion with several referenced models about reason for behavior of Ni-DLC.
Journal: Diamond and Related Materials - Volume 20, Issues 5–6, May–June 2011, Pages 814–818