DEVELOPMENT OF SOL-GEL DERIVED NANOCERAMIC FOR INFRARED SENSING DEVICES

Abstract

Many advanced ceramics are used as sensors such as temperature, pressure, gas, humidity and infrared sensors. These sensors are based on various properties of the ceramics, for example, grain boundary and grain size, piezoelectric effect, oxygen ion conductivity or controlled pore structures. Current research is focused on method for the production of high surface area nanoparticles and nanocomposites. Recently some attention has been paid to develop some piezoelectric and pyroelectric composites made from polymer and ferroelectric ceramics for improvement of some of the properties of these materials. From the literature survey on ABO3 type compounds, it was found that some of the oxides, such as ABO3 (A= Ca, Ba, Sr, Cd, Pb; B= Ti, Sn, Zr, Nb, Ta) have extensively been studied. Easy preparation of fine powder, large dielectric and piezoelectric constant and high electro-optical coefficient of Pb(Zr/Ti)03 (PZT) have attracted our attention to prepare the complex solid solutions of PZT. Here we report the structural and electrical properties of the prepared PZT ceramics by sol-gel technique. Polycrystalline samples of Pb(Zro.53 Ti0,47 )03 have been synthesized by the coprecipitation method. X-ray diffraction and FTIR analysis suggests the formation of the single-phase compound. The scanning electron microscopy (SEM) study shows the uniform distribution of grains in the sample and the particle size of the compound is --25μm. Differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) (from room temperature to 1500°C) of the coprecipitated compound has been done to know the temperature of formation of the compound and its thermal stability. Detailed dielectric studies of the compound as a function of temperature (from 20°C to210°C) at 1 KHz, 10 KHz and 100 KHz shows that the compound under goes a diffuse phase transition. Diffusivity (y) study of phase transition of this compound provides its value between 1 and 2, indicating the variation of degree of disordering in the system.