Materials Science Forum, Vol.455-456, 560-563, 2004
Activated sintering of TiC-TiB(2)SHS-powders
This work is part of a research project directed to the manufacture of high performance cutting tools by consolidation of ceramic powders produced by SHS (Self-propagating High Temperature Synthesis). The process used here was based on low/medium cost raw materials. The reaction of TiO(2) and B(4)C with carbon and magnesium took place in. argon atmosphere, yielding a TiC-TiB(2) powder. In view of further liquid phase sintering as a TiC-TiB(2) metal-bonded cermet, an extensive investigation on the sintering additives was performed. The most suitable metallic binders turned out to be Ni and Fe. The best results were achieved through addition of Mo(2)C as wettability activator to the metallic Ni phase. In particular, the vacuum sintering of the system 60%TiC-40%TiB(2) with a binder addition of 15%Ni-7.5%Mo(2)C led to the achievement of cermets characterised by a sintered density of 95% of theoretical density and homogeneous microstructure. The hardness measurement on the sintered samples showed the achievement of good results (1650 HV), qualifying the new developed cermet compositions as suitable for cutting tools and wear-resistant applications.
Keywords:nanostructured materials;self-propagating high temperature synthesis (SHS);powders;sintering