title: Strontium-doped hematite as a possible humidity sensing material for soil water content determination.
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.
authors.affiliation: Department of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino, Italy. jeanmarc.tulliani@polito.it.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Tulliani
authors.forename: Chiara
authors.initials: C
authors.lastname: Baroni
authors.forename: Laura
authors.initials: L
authors.lastname: Zavattaro
authors.forename: Carlo
authors.initials: C
authors.lastname: Grignani
mesh_terms: D004784:Environmental Monitoring / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005290:Ferric Compounds / Q000737:chemistry*; D006813:Humidity; D012987:Soil / Q000737:chemistry*; D013324:Strontium / Q000737:chemistry*; D014159:Transducers; D014867:Water / Q000032:analysis*
chemical_list: D005290:Ferric Compounds; D012987:Soil; D014867:Water; C000499:ferric oxide; D013324:Strontium