Influence of processing condition of Ti, Al, and B2O3 mixed powders on the preparation of Al2O3-40.5 mass % TiB2 sintered compact by HIP

Abstract

The Al2O3–TiB2 sintered compact was synthesized by a reaction, Ti + 2Al + B2O3 = Al2O3 + TiB2, during hot isostatic press (HIP) with mixed powders of Ti, Al and B2O3 as starting materials. It was found that pre-cooling at −5°C and milling at 0°C suppress the reaction to proceeding mechanochemically, and extend the time for mixing. Scraping off clung powders inside of container during the milling made powders fine and uniform. The longer milling time and uniformity of the powders achieved by the above treatments made it possible to obtain Al2O3–40.5 mass % TiB2 with 99.5% relative density and Hv = 2800.