Barium titanate (BaTiO$sb3$) and barium tetratitanate (BaTi$sb4$O$sb9$) are two important compounds in the BaO-TiO$sb2$ system widely utilized in the manufacture of the thermistors, multilayer capacitors, electro-optic devices and microwave resonators. The performances of these electronic ceramics heavily depend on their microstructure. Chemical processes, which can improve the microstructure and significantly enhance their performance, are of great technical interest.;An important, rather novel procedure for bulk syntheses of BaTiO$sb3$, BaTi$sb4$O$sb9$ and $rm Pbsb{x}Basb{1-x}Tisb4Osb9$ has been investigated. $rm Ba(NOsb3)sb2, TiO(NOsb3)sb2, Pb(NOsb3)sb2$ and alanines are intimately mixed by spray drying an aqueous solution of them. Incandescent oxidations occur when the spray dried mixtures are heated to 300$spcirc$C. Alanines serve as reducing agents which react with nitrate. The heat evolved from the reactions converts the mixtures to $rm BaTiOsb3, BaTisb4Osb9$ and $rm Pbsb{x}Basb{1-x}Tisb4Osb9$ directly. The selections of alanines as reducing agents and 300$spcirc$C for the reaction are based on thermal decomposition of the spray dried mixtures tested by TG/DTA.;XRF indicates good stoichiometry between barium and titanium in the BaTiO$sb3$. The as-prepared BaTiO$sb3$ contains a small amount of carbonate that can be eliminated by heating the powder at 900$spcirc$C for an hour. Therefore, high purity BaTiO$sb3$ can be obtained by that heating step. The particle size of the BaTiO$sb3$ has been measured by XRD line broadening, SEM, BET and Fraunhofer laser diffraction. SEM micrographs indicate 0.1 $mu$ particle and very even distribution. The sinterability of the powder is characterized by thermodilatometry of a pressed pellet over the temperature range from 600 to 1400$spcirc$C. Three stages of sintering are observed. The activation energy for the last stage has been determined by the Ozawa method to be 4.2 $times$ 10$sp6$ Joule/mole. Impedance spectra and densities of the sintered pellets have been measured.;$rm Pbsb{0.5}Basb{0.5}Tisb4Osb9$ and $rm Pbsb{0.2}Basb{0.8}Tisb4Osb9$ are prepared for the first time by this combustion synthesis method and have never been reported before. $rm Pbsb{0.5}Basb{0.5}Tisb4Osb9$ is found unstable above 800$spcirc$C. It decomposes to $rm BaTisb5Osb{11}, PbTiOsb3$ and TiO$sb2$ upon heating to 900$spcirc$C. Lattice constants of these compounds have been calculated according to their powder XRD. They are linear with the molar fraction of lead.;The method should be applicable to the synthesis of other compounds in the BaO-TiO$sb2$ system and can easily and uniformly introduce dopants and major substitutions into the desired compounds. It offers a new route to synthesize novel, metastable compounds, which cannot be prepared by conventional methods and which may have undiscovered properties and great technical importance.
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