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2011
Presentation
Titel
Boron suboxide (B6O) with oxide additives for cutting and wear applications
Titel Supplements
Presentation held at 12th Conference of the European Ceramic Society 2011, Stockholm, Sweden, 19-23 June 2011
Abstract
With a hardness up to 45 GPa measured on single crystals and a fracture toughness even exceeding that of cubic boron nitride (cBN), boron suboxide (B6O) is a promising candidate for wear and cutting applications. Additionally recent work has shown that B6O may be synthesized cost-effectively near ambient pressure which is a main advantage towards established cBN and diamond based hard materials. However, pure ceramic B6O materials are difficult to densify and are characterized by low fracture toughness < 2 MPam1/2. Therefore, the use of liquid phase forming additives may be a promising way for both assisting sintering and improving fracture toughness. The results of a systematic investigation of the influence of different amounts and ratio of Al2O3/Y2O3 oxide additives on densification and microstructure formation are given. Even low amounts of additives significantly decrease the required sintering temperature. Fracture toughness could be improved up to 3.6 MPa*m1/2 while the hardness is only marginally lowered as compared to pure B6O materials. Values up to 36 GPa (HV0.4) were measured. The hardness at high temperatures exceeds that of cBN materials. Therefore these materials could be a suitable candidate for cutting applications.