High pressure sintering of B6O powder and properties of sintered compact
Itoh Hideaki; Maekawa Ichiro; Iwahara Hiroyasu
Abstract:B6O sintered compacts were prepared by high pressure and temperature treatments of in laboratory synthesized B6O powder. Sinterable B6O powder with grain sizes of 1.2 - 1.4mm was formed above 1300 deg. in 4 hours in a pure argon stream by a solid liquid reaction between amorphous boron and B2O3 powders. Single phase sintered compacts with relative densities above 95% were obtained under the sintering condition of 3 5GPa, 1700 deg. and 20 min. The Vickers microhardness of the sintered compact was 31 - 33GPa. The B6O sintered compact exhibited an oxidation resistance in air up to 600 deg. and a mild oxidation behavior in the temperature range of 700 - 1000 deg. with the formation of a liquid protective film of B2O3. Key Words:boron suboxide, sintered compact, high pressure sintering, supper-hard materials, oxidation resistance