%0 Journal Article
%T Strontium-Doped Hematite as a Possible Humidity Sensing Material for Soil Water Content Determination
%A Jean-Marc Tulliani
%A Chiara Baroni
%A Laura Zavattaro
%A Carlo Grignani
%J Sensors
%D 2013
%I MDPI AG
%R 10.3390/s130912070
%X 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 ¡ãC. 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¨C1,000 ¡ãC 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.
%K hematite
%K strontium hexaferrite
%K humidity sensor
%K soil water content determination
%U http://www.mdpi.com/1424-8220/13/9/12070