Strontium-doped hematite as a possible humidity sensing material for soil water content determination

Sensors (Basel). 2013 Sep 10;13(9):12070-92. doi: 10.3390/s130912070.

Abstract

The aim of this work is to study the sensing behavior of Sr-doped hematite for soil water content measurement. The material was prepared by solid state reaction from commercial hematite and strontium carbonate heat treated at 900 °C. X-Ray diffraction, scanning electron microscopy and mercury intrusion porosimetry were used for microstructural characterization of the synthesized powder. Sensors were then prepared by uniaxially pressing and by screen-printing, on an alumina substrate, the prepared powder and subsequent firing in the 800-1,000 °C range. These sensors were first tested in a laboratory apparatus under humid air and then in an homogenized soil and finally in field. The results evidenced that the screen printed film was able to give a response for a soil matric potential from about 570 kPa, that is to say well below the wilting point in the used soil.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Environmental Monitoring / instrumentation*
  • Equipment Design
  • Equipment Failure Analysis
  • Ferric Compounds / chemistry*
  • Humidity*
  • Soil / chemistry*
  • Strontium / chemistry*
  • Transducers*
  • Water / analysis*

Substances

  • Ferric Compounds
  • Soil
  • Water
  • ferric oxide
  • Strontium