Research On SrTiO₃Capacitance-Pressure Sensitive Composite Function Ceramics Rheostat Dielectric Properties

SrTiO3composite ceramics is a new type of pressure-sensitive semiconductor ceramics, with good dielectric properties, can be used to fabricate piezoresistor and boundary layer capacitor, widely used in various fields, especially important in the overvoltage protection.This experiment using a blending method, namely in weighing the SrTiO3base powder, an incorporation of various modifying dopant, then ball milling. Ball milling method for dry grinding, replace the traditional need to join the ion water as dispersing agent of wet grinding. Sintering atmosphere environment sintering in vacuum environment using vacuum carbon tube furnace building to replace the traditional hydrogen and nitrogen, and safe experimental process. Vacuum sintered samples and then into the boiling two sintering, the last electrode test and dielectric properties.Selection of Nb2O5as a donor doping, MnCO3and CaCO3as acceptor-doped,SiO2as sintering aids. Using vacuum reducing sintering promoting grain of semi-conducting technology on SrTiO3capacitance-pressure sensitive composite dielectric properties of functional ceramics rheostat has carried on the experiment. Experimental results show that:the double acceptor doped samples with CaCO3as a single acceptor doping prepared samples compared with the nonlinear coefficient increased, SEM scanning display sample grain size is more dense. SiO2as sintering additives can effectively reduce the sintering temperature. Experiments of the preparation of SrTiO3compound functional ceramics overall performance is good, the dielectric properties in the following areas:the scope of nonlinear coefficient is4.1 12.3, the scope of the dielectric constant epsilon is2.1×104～8.5×104, ressure-sensitive voltage V1mA range of20～90V/mm, dielectric loss tan delta range of0.24～0.24.