METHOD OF PRODUCING ALUMINA NANOCERAMIC Russian patent published in 2010 - IPC C04B35/10 C30B28/00 C30B29/20 B82B3/00 

FIELD: chemistry.

SUBSTANCE: invention relates to production of optical materials which are transparent in the infrared (IR) spectrum with high transmission coefficient and high mechanical strength. The method involves preparation of a colloidal solution from finely dispersed γ-Al₂O₃ powder, from which a transparent supernatant - sol is extracted, which, through ultrasonic treatment, heating, acidification and thickening, is brought into a state gelling takes place after several days - formation of a viscous sol which is poured into a moulding hydrophobic container, where the said sol is kept until a moulded volume of gel is formed - gel workpiece. After removal from the mould, the gel workpiece undergoes thermal treatment in several steps, preferably three steps, where in each subsequent step temperature is approximately doubled, and the obtained polycrystalline mechanical strong material undergoes sintering at 1200-1750°C at pressure of 30-300 MPa for 20-30 minutes, after which temperature of furnace is brought down to ambient temperature under inert conditions.

EFFECT: invention enables to obtain high-quality optical polycrystalline material from structured elements with dimensions of several nanometres and having high optical transparency in the visible an infrared spectra and high mechanical strength which is 3-5 times higher than that of ceramics with micro-sized particles, as well as obtaining material for the input lens of a photodetector which, while retaining main optical parametres, has properties required for material for this purpose - heat resistance, thermophysical stability in a high-temperature plasma current.

6 cl, 1 ex, 1 tbl