Study On Good BaTiO₃ Powders For Electronic Ceramics

BaTiO3, a kind of electronic ceramics with high dielectric constant, is useful for the manufacture of multilayer ceramic capacitors, thermistors and electro-optic components. Routes for synthesis BaTiO3, technical characteristics, research status and recent progress have been presented in this paper firstly. Low temperature wet chemical routes offer an exciting possibility for the synthesis of high purity, homogeneous, ultrafine powders which meet the need of electronic components in factual application. Sol-gel Autoignition Synthesis, simple, self-cleaning and easy to undertake scale production, is the one of the prospective routes for manufacturing barium titanate powders.BaTiO3 nanopowders with the particle size 20-90nm, specific surface area 15m2/g, fine particle distribution, ratio of Ba/Ti 1.002 and with the dielectric constant more than 3000, were synthesized by SAS BaTiO3-TiCl4-ammonia-citric acid system. And BaTiO3-Ti(OC4H9)4-ammonia-citric acid system, another useful system was also set up successfully.With complexometric titration and gravimetry, the content of titanium in TiCl4, Ti(OC4H9)4 and TiO(NO3)2 as raw material and intermediate product for preparation of BaTiO3, as well as the content of barium and titanium in the end product were determined. The method applied was simple, rapid and accurate, which has been used for the analysis and control of the synthesis of barium titanate nano-powder.Specific surface area, one of the important properties that powders have, can express particle size and the value of it is related with the particle shape , appearance and so on. It is very important to set up the measuring method of particle size for people to control powders properties and its manufacturing process. This experimentmade use of simple BET equipment to measure the specific surface area of BaTiO3.Monodispersed particle is also an important index for powders with good property. Sedimentometry is the most common method applied to measure particle size and distribution which may be used more than any other measuring instrument. In this method, we can calculate the particle distribution by means of monitoring particle sediment velocity in the fluid. In this experiment, the distribution of barium titanate powders was obtained in this way by centrifuge photosediment equipment made in Japan.