METHOD OF OBTAINING CONSTRUCTIONAL ALUMINA CERAMICS Russian patent published in 2015 - IPC C04B35/111 C04B35/626 C01F7/42 

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of ceramic materials for the constructional purpose and can be applied for the production of porous products for high-temperature heat-insulation or heat-protection, carriers of catalysts and filters for the purification of liquid and gas media. To obtain constructional alumina ceramics an aluminium alloy, which includes (wt %): lithium 1.2-1.5, silver 0.1-0.3, zinc 0.05-0.2, copper 3-5, manganese 0.03-0.07, iron 0.25-0.4, magnesium 0.02-0.1, silicon 0.03-0.2, nickel 0.06-1, chromium 0.06-0.1 and aluminium - the remaining part, is subjected to rolling with relative cobbing of 50-70% with the removal of chips which consist of fragments with the area of 160-230 mm² and width of 0.1-0.2 mm. After annealing in vacuum at a temperature of 450-500°C the chips are processed with a NaOH water solution until sediment is formed in mother liquor. The sediment is extracted, washed, dried and thermally processed in air at 1350°C for 1 hour, then milled, an air brick is pressed and sintered in air at a temperature of 1500°C for 1 hour. The phase composition of ceramics is: α-Al₂O₃ (base), CuAl₁₂O₁₉, NaAl₁₁O₁₇ and X-ray amorphous phases. The open porosity is 44-48%, the flexural strength is 40-55 MPa, relative loss of the flexural strength after 15 thermo-cycles (1000°C - air) is 3-7%.

EFFECT: increase of the material thermal resistance in conditions of successive multiple thermo-cycles with the preservation of a sufficiently high strength.

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