Preparation and properties of ceramic sensor elements based on MgCr2O4

Abstract

Using TiO₂, ZrO₂ and SnO₂ as additives, the intrinsic electrical resistivity-humidity characteristics of MgCr₂O₄ material used for humidity sensors is varied. By choosing a particle size fraction of the starting powders with a radius less than or equal to 1 μm and varying the sintering temperature from 1200 °C to 1500 °C, the sintered porosity and pore-size distribution of the sensor ceramic elements are controlled. By macerating the ceramic elements with solutions of various salts containing CO₃²⁻ ions, the sensitivity of the impedance of the sensor elements to CO₂ in air is diminished.