METHOD OF PREPARING ALKALI AND ALKALI-EARTH METAL TITANATES, ZIRCONATES, AND NIOBATES Russian patent published in 1997 - IPC

FIELD: nonferrous metallurgy; inorganic syntheses. SUBSTANCE: in order to increase purity and homogeneity of product and at the same time reduce its cost, synthesis is carried out in the mode of self-propagating high-temperature synthesis, wherein exothermicity of reaction of alkali and alkali-earth metal nitrates with oxides in presence of carbon or corresponding metal (titanium, zirconium, niobium) carbide is utilized. Reaction blend is prepared with following molar proportions of components: alkali metal nitrate : oxide : carbon (carbide) = 2:1:(1.0-2.5); alkali-earth metal nitrate : oxide : carbon (carbide) = 1:1:(1.0-2.5). A part of nitrate (up to 50 mol %) may be replaced with equimolar quantity of corresponding alkali or alkali-earth metal carbonate. Possible is also substitution of a part (up to 50%) of oxide by equimolar quantity of titanium, zirconium, or niobium carbide, substitution being performed in the following molar proportions: titanium or zirconium oxide to carbide = 1:1, and niobium oxide to carbide = 1:2. Prepared substances can be employed for manufacturing ceramic dielectrics. EFFECT: optimized parameters of synthesis resulting in increased purity of products. 3 cl, 2 tbl