PREPARATION OF TITANIUM DIBORIDE FROM THE BOROTHERMIC REDUCTION OF TIO2, TIOX(OH)Y, OR TI(O-N-BU)4-DERIVED POLYMERS

The reaction between amorphous boron powder and TiO2, TiOx(OH)y or tit anium-alkoxide derived polymers (B: Ti = 4:1) was studied at 25-1500-d egrees-C in a flow of argon. The borothermic reduction of TiO2 resulte d information of Ti2O3 and TiBO3 at 600-degrees-C; TiB2 was formed by further borothermic reduction of Ti2O3 and TiBO3 above 700-degrees-C; the overall reaction was found to be complete at 1300-degrees-C. The p article sizes of TiB2 powders obtained were directly related to the st arting material used as the titania source. The largest particles were obtained when TiO2 powder was used as the starting material. The part icles were smaller when TiOx(OH)y powder was used, and the smallest pa rticles were obtained when the partially-hydrolyzed Ti polymer, [BuOTi O1.5]n, was used as the titanium source. The pyrolysis chemistry of th ese precursors as well as the morphology of the pyrolysis products wer e studied by FT-IR, TGA, SEM, XRD, BET, elemental analyses and particl e size analyses.