BAKED CERAMIC MATERIAL BASED ON ALUMINUM OXIDE AND PROCESS FOR PRODUCING BAKED CERAMIC MATERIAL Russian patent published in 1994 - IPC

FIELD: manufacture of ceramic powdery materials. SUBSTANCE: this method is used for producing baked ceramic material containing 95 to 99 percent by mass aluminum oxide and 1.0 to 5.0 percent by mass titanium dioxide. The least percentage (95 %) of crystallites have grain size of less than 4 microns (preferably less than 2 microns), preferable microhardness either equal to or less than ≥ 18 GPa and breaking strength of either equal to or less than ≥ 2 MPa·m^1/2 (preferably equal to or less than ≥ 4,5 MPa·m^1/2. Material may contain about 0.01 percent by mass additive selected from group including SiO₂, MgO, ZrO₂, MgAl₂O₄, MgTiO₃, α-Fe₂O₃, NiO, FeAl₂O₄, NiTiO₃, NiAl₂O₄, α-A₂O₃, α-Cr₂O₃, CeO₂, ZnTiO₃, ZnAl₂O₄, and Y₂O₃. Material is prepared by preparing sol, formation of gel, drying, comminuting, fractionating, molding and baking prepared stock. Sol contains finely divided or highly dispersed component selected from group including TiO₂ and/or Al₂TiO₅ and Al₂O₃ and/or substance that decomposes to form TiO₂ and/or Al₂TiO₅ and Al₂O₃. Material is baked with two standings, one at temperature of 300 to 700 C and another at temperature of 1250 to 1500 C. Baking step may be followed by repeated thermal treatment of T₂ at 800 to 1300 C. However, T₂ temperature is by at least 20 C lower than baking temperature. Baking process may be run at atmospheric pressure. Either boehmite or Al(OH)₃ is used as prescribed aluminum compound. EFFECT: more sophisticated technique. 13 cl, 6 tbl