Microstructure and electrical properties of Si-doped α-Fe2O3 humidity sensor

✍ Scribed by C. Cantalini; M. Faccio; G. Ferri; M. Pelino

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 504 KB
• Volume: 16
• Category: Article
• ISSN: 0925-4005
• DOI: 10.1016/0925-4005(93)85198-j

✦ Synopsis

The humidity sensitivity of Si-doped x-hematite sintered compacts was investigated by precision volt-amperometric and impedance spectroscopy techniques in the 0-95% relative humidity (r.h .) range. 130 m2/g specific area a-hematite powders were dispersed in 3-amino-propyl-trihydroxy-silane solution and dried at 120 °C to yield 2 wt .% Si. Sintering was performed at 50 °C steps in the temperature range -850-1100 °C . Compacts were characterized by SEM, mercury intrusion and nitrogen adsorption techniques . The electrical response of Si-doped %+e2 03 Was affected by the microstructure and sintering temperature . The 850-950 °C sintered compacts showed a linear response of impedance, in the logarithmic scale, in the whole investigated r .h. range . The variation of impedance was measured from 101 (0% r.h.) to 10° ohm (95% r .h.). The response times of the sensors were evaluated by 0-60 r .h. variations . The results were compared with undoped sintered compacts .