METHOD OF PRODUCING HIGHLY POROUS CORUNDUM CERAMICS Russian patent published in 2024 - IPC C04B35/10 C04B35/64 B22F3/11 B22F3/12 

FIELD: ceramic materials.

SUBSTANCE: invention relates to the technology of ceramic materials and can be used for making highly porous corundum articles, used as light high-temperature heat insulation, heat-shielding coatings, filters for liquids and hot gases, as well as catalyst carriers. Method involves mixing hollow corundum microspheres with an aqueous solution of a hardening binder, loading the mixture into a mould and drying it in air until the binder hardens, removing the green article from the mould, heat treatment in air and sintering in a vacuum, wherein the hardening binder used is a solution of sodium hydrosilicate in amount of 15 to 18 wt.% in terms of the dry residue of the substance with respect to the weight of the hollow corundum microspheres, aluminium powder, consisting of scaly particles with a ratio of the mass of hollow corundum microspheres to the mass of aluminium powder from 5.8:1 to 7.0:1, is added to the sodium hydrosilicate solution, after loading the mixture into the mould, it is compacted by pressing the punch under pressure of 1.6⋅10^-2 to 3.2⋅10^-2 MPa, thermal treatment of the raw product in air is carried out by heating at rate of 300–350 °C/hour to temperature of 600–650 °C with isothermal holding for 30–35 minutes, then heating is carried out at rate of 300–500 °C/hour to temperature 1,590–1,630 °C with isothermal holding for 15–30 minutes, sintering in vacuum is carried out at temperature of 1,650–1,700 °C with isothermal exposure for 30–45 minutes.

EFFECT: increased strength of raw material and sintered material with increase of its porosity and reduction of sintering temperature.

1 cl, 3 dwg, 1 tbl, 3 ex