FORMATION AND SINTERING OF TIO2 (ANATASE) SOLID-SOLUTION IN THE SYSTEM TIO2-SIO2

In the TiO2-SiO2 system, anatase solid solutions (ss) containing up to approximate to 15 mol% SiO2 are formed in the as-prepared state by th e hydrazine method. The lattice parameters a and c decrease linearly f rom 0.3785 to 0.3776 nm and from 0.9514 to 0.9494 nm, respectively, wi th increased SiO, content, At high temperatures, the solid solutions b y transformation decompose into rutile and amorphous SiO2, The anatase (ss) powders have been characterized for particle size and surface are a, They consist of very fine particles (7-25 nm). Surface areas at low temperatures are very high and do not drop below 60 m(2)/g at 1000 de grees C. Nanostructured anatase(ss) ceramics, with greater than or equ al to 99.5% of theoretical density and an average grain size of 72 nm, have been fabricated by hot isostatic pressing for 1 h at 850 degrees C and 196 MPa. Their mechanical and electrical properties have been e xamined.