A synthetic diamond conductivity sensor: Design rules and applications
[Display omitted] •First example of a conductivity sensor fabricated entirely from synthetic diamond.•Two point probe configuration capable of conductivity measurements over six orders of magnitude.•Conducting diamond electrodes show corrosion resistance.•Ability to make solution conductivity measur...
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Veröffentlicht in: | Sensors and actuators. B, Chemical Chemical, 2017-01, Vol.238, p.1128-1135 |
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Format: | Artikel |
Sprache: | eng |
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•First example of a conductivity sensor fabricated entirely from synthetic diamond.•Two point probe configuration capable of conductivity measurements over six orders of magnitude.•Conducting diamond electrodes show corrosion resistance.•Ability to make solution conductivity measurements in 98% sulfuric acid.
Solution conductivity sensors (electrodes) are widely used in industrial and research settings to make measurements across the wide range of conductivities found in aqueous solutions, from distilled water to concentrated salts and acids. However, changes in electrode geometry as a result of mechanical wear, surface fouling or chemical attack result in changes to sensor performance, necessitating regular recalibration. Furthermore, direct contact with solution means exposed electrodes are susceptible to surface fouling or corrosion. In this paper we describe, a corrosion resistant, mechanically robust conductivity sensor fabricated from synthetically grown insulating and conducting diamond, using scalable chemical vapor deposition. In particular, using a two-step growth procedure pairs of co-planar conducting diamond band electrodes are integrated into an insulating diamond platform in a two point probe arrangement on a 10mm×10mm diamond platform. The all-diamond sensor is demonstrated to be capable of determining solution conductivity over six orders of magnitude (10−1 to 105μScm−1). Longer term continuous measurements (two month period) show this sensor performs just as well as a commercially available sensor (four point probe arrangement). The exceptional chemical resistance of diamond is demonstrated by using the sensor to measure the conductivity of 98% sulfuric acid. In general, these measurements bode well for the development and application of synthetic all-diamond conductivity sensors over extended periods of time, in-situ and in challenging pH environments. Finally, the use of diamond also opens up high pressure/high temperature solution conductivity applications for this sensor. |
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ISSN: | 0925-4005 1873-3077 |
DOI: | 10.1016/j.snb.2016.06.069 |