METHOD FOR OBTAINING POROUS ALUMINIUM OXIDE CERAMICS Russian patent published in 2017 - IPC C04B35/111 C04B35/65 C04B38/08 

FIELD: metallurgy.

SUBSTANCE: for manufacturing of porous aluminium oxide ceramics, charge is obtained by mixing aluminium powder of PAP grade in amount of 30-70 vol %, alominium oxide powder consisting of porous spherulites, and aqueous solution of PVOH (2-7 wt % on dry basis). Aluminium powder is heated in advance to 360-370 °C and matured for 3-5 hours, and aluminium oxide powder undergoes thermal treatment at 1320-1370 °C for 1-3 hours. Raw material is obtained from dried charge by pressing at 50-500 MPa and used to burn PVOH out at 340-355 °C for 1-5 hours, followed by thermal treatment in the air by heating at 20-25 °C/minute rate to 500-550 °C with ageing for 5-15 minutes, then heating continues at 20-30 °C/minute to 700-750 °C with further ageing for 10-30 minutes and is followed by caking in the air at 1450-1500 °C for 0.5-1.0 hours. Phase composition of ceramics is represented by α-Al₂O_3, total porosity comprises 42-52 %, open porosity is 38-50 %, bending strength is 10-50 MPa, heat conduction factor in the air at 1000 °C is 1.8-2.3 W/m⋅K.

EFFECT: increased share of open porosity of material, improved thermal resistance with high strength preserved.

6 cl, 1 tbl, 2 dwg