METHOD OF MANUFACTURING TRANSPARENT ALUMINA CERAMICS Russian patent published in 1997 - IPC

FIELD: ceramics production. SUBSTANCE: invention relates to technology of transparent polycrystalline aluminium oxide applicable, in particular, to manufacturing high-pressure gas-discharge sodium lamp tubes. Invention aims at reducing shrinkage of stocks when baked, accelerating stock baking process, and reducing power consumption on liquid evaporation. Aim is achieved by way of producing transparent alumina ceramics from aluminium oxide alcohol solution including hydrolysis of alkoxide, removing solvent and all side products from mixture, disintegrating gel, pressing and vacuum baking stocks, wherein hydrolysis is performed with aqueous solution of compacting additive, water to alkoxide molar ratio being (3-5):1. Before stock pressing operation, aluminium hydroxide powder is converted into corundum powder upon heating in oxidizing atmosphere with rate 300- 500 C/h to maximum temperature 950-1150 C and aging for 100-200 min followed by cooling together with kiln. As compacting additive, a mixture of water-soluble magnesium, yttrium, and lanthanum salts is used in amount not exceeding (on conversion to oxides) 0.2 wt % based on equivalent content of aluminium oxide. EFFECT: enhanced efficiency of process and reduced cost. 2 cl, 1 tbl