Nanocorundum - Advanced Synthesis and Processing
Inorganic and organic approaches are described for the synthesis of redispersible corundum powders with particle sizes of about 50 nm (vol-%). A key issue of advanced processing is the preparation of dense sintered bodies at < 1300 degC and with a sub-5m grain size; the bodies are large enough to enable the measurement of a Vickers macrohardness HV10 > 21 GPa. Porous sintered corundum bodies and membranes have been produced with average pore sizes between 15 and 60 nm (and > 100 nm) and with equiaxed pore shape by both powder and sol/gel approaches within the framework of the new ssynthesis; they are applied as chemically and thermally highly stable filtration membranes or as catalyst supports. Other applications of the new synthesis are the preparation of amorphous or crystalline nanoporous Al2O3 products.