| Nowadays, it's believed that the development trends of multi-layer ceramic capacitor (MLCC) production and technology would be micromation, high specific capacitance, high voltage, low production cost and high reliability. However, the key to the manufacture of high capacitance MLCC is to reduce the thickness of each layer and increase the number of layers. To achieve this target, the vital step must be the preparation of nano-sized or submicron-sized ceramic powder.Barium-titante (BaTiO3) is the primary material for high dielectric constant ceramic capacitors and multi-layer ceramic capacitors manufacture due to its excellent electronic performance, such as ferroelectric, piezoelectric, high dielectric constant and positive temperature coefficient effect, etc. If the nano-sized BaTiO3 powder can be prepared, then it will realize the material of manufacturing thin-layer, high capacitance, high reliability MLCC which may replace the position of tantalum and aluminium capacitors. At present, with the advancement of ultrafine high performance medium ceramic material research and technology, the layer thickness of MLCC has been reduced to submicrongrade and the layer number raised to over 600. However, regarding to the preparation of nano-sized or submicrpn-sized BaTiO3 powder, using the traditional TiO2 and BaCO3 solid sintering technology is a very difficult way, while using hydrochemical method to prepare the precursor of ultrafine BaTiO3 and then calcining it to get the ultrafine powder is a relatively more applicable one. The ceramic powder prepared by this method can be highly squandered in one thin layer because of its ultrafine particle size and that ensures the consistency of same layer and multi-layer which is the basis of MLCC's electronic performance and reliability.In this article the barium-titante preparation techniques in recent years have been summarized, their respective advantages and disadvantages compared, and then a experimental scheme of preparing ultra-fine barium-titante powder for multi-layer ceramic capacitor by carbonate coprecipitation synthesis worked out. In order to make contrast, two different ways, EbTiOa coprecipitation and TiCl4 coprecipitation, have been carried out respectively to synthesize the ultra-fine BaTiO3 powder. The influences of barium to titanium ratio, TiOSO4 concentration, TiCl4 concentration, amount of surfactant, reactant applying method, reaction temperature, reaction time, calcinations temperature and etc. on the powder properties have been investigated. The powder's crystal constitution, composition, particle shape and size have been measured using SEM, XRD and laser particle sizing instrument. The following experiment results have been achieved: Coprecipitating H2TiO3, the middle product of vitriolic titanium manufacture, used as titanium source, with BaCl2-2H2O and (NH4)2CO3 can synthesize ball-shaped nano barium-titante powder with an average particle size of 100 nm. Using the technique mentioned above to prepare barium-titante, the precipitation does not need heating, the progress is simple and easy to be controlled. Compared with techniques ashydrothermal synthesis and etc., the coprecipitation synthesis does not have special requirements for apparatus and reaction environment thus the investment on hardware and consume of energy can be cut down. The optimized reaction conditions of this technique are: titanyl vitriol solution's concentration: 0.4mol/L; BaCl2-2H2O to H2TiO3 ratio: 1.04; (NH4)2CO3 to BaCl22HbO ratio: 1.08; reaction temperature: room temperature (about 25 centigrade); reaction time: 1.5 hours; calcination temperature: 920 centigrade; calcination time: 2 hours.Coprecipitating TiCU with BaCl2-2H2O and NH4HCO3 can synthesize ball-shaped nano barium-titante powder with an average particle size of 0.1-0.3 jo.m. The TiCU coprecipitation synthesis has advantages of short technique flow length, operation simplicity and quality stability. The optimized reaction conditions are: TiCU concentration 0.6M, NH4HCO3 to BaCh ratio: 1.2; fina...
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