cBN composites with nanosized binding phase
|Wioletta Gorczyńska-Zawiślan 1, Ewa Benko 1,2, Piotr Klimczyk 1|
1. Institute of Metal Cutting, Wrocławska 37A, Kraków 30-011, Poland
The cubic boron nitride (cBN) is the second hardest material next to diamond. Because of its many excellent physical and chemical properties cBN is even considerably superior to diamond in two areas where diamond`s performance is poor: its abrasion resistance with ferrous alloys, such as steels and its oxidation resistance. The cBN-ceramics shows high mechanical properties and cutting tools made from it are being widely used for cutting hardened steels, cast iron and nickel-based superalloys. Ti and their compounds are widely used as a binding phase and as a layered phase in the cBN composites. In the present work cBN-TiN composites were investigated. These composites were made using HPHT technique (p=8 GPa, T=1750 0 C). The TiN binding phase was used in two forms: as micro and nanomaterials. From thermodynamical calculations it followed that formation of new phases in the cBN-TiN composites is not possible in the investigated conditions. XRD investigations confirmed that no new phases were formed in the cBN-TiN systems studied. Surface morphology of BN-TiN nanocomposites was observed by scanning electron microscopy. The structure of these composites is compact; TiN phase is uniformly distributed between cBN grains. Hardness was measured by Vickers method using an indentation load of 9.81 N. Hardness of the investigated samples depends on the volume and grain size of the binding phase. Young's modulus of elasticity was measured. It was found that its value depends on the grain size of the TiN phase.
Presentation: poster at E-MRS Fall Meeting 2004, Symposium G, by Wioletta Gorczyńska-Zawiślan
See On-line Journal of E-MRS Fall Meeting 2004
Submitted: 2004-05-26 12:12 Revised: 2009-06-08 12:55