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S. Wawrzik, T. de Barros, W. Lengauer:
"Surface- and Interface-Zone Evolution of Cermets and Cermet/Hardmetal Laminates";
Poster: 18. Plansee Seminar 2013, Reutte; 06-03-2013 - 06-07-2013; in: "Proceedings", (2013), 1 - 13.

A (Ti,W)(C,N)-Co/Ni cermet grade without free hexagonal WC and (Ti,W)(C,N)-Co/Ni - WC-Co laminates were studied with respect to bulk microstructure, cermet surface and cermet/hardmetal interface evolution depending on the sintering temperature and atmosphere. Therefore, the samples were subjected to interrupted sintering profiles up to 1460°C with various nitrogen pressures. Free WC formation near the surface is strongly dependent on the nitrogen pressure. The onset of surface zone modification is located around 1300°C, where open porosity is still present.
In the cermet/hardmetal laminates the bonding of cermets to the hardmetals and that of mixtures 50% hardmetal + 50% cermet, 33% hardmetal + 66% cermet and 66% hardmetal + 33% hardmetal to cermet or hardmetal, respectively, is tight and gapless in most cases. No major distortion or bending is observed although the shrinkage of each of the alloys is quite different. With some combinations a clearly visible graded diffusion zone forms, partially with microstructures different from the starting material.

A (Ti,W)(C,N)-Co/Ni cermet grade without free hexagonal WC and (Ti,W)(C,N)-Co/Ni - WC-Co laminates were studied with respect to bulk microstructure, cermet surface and cermet/hardmetal interface evolution depending on the sintering temperature and atmosphere. Therefore, the samples were subjected to interrupted sintering profiles up to 1460°C with various nitrogen pressures. Free WC formation near the surface is strongly dependent on the nitrogen pressure. The onset of surface zone modification is located around 1300°C, where open porosity is still present.
In the cermet/hardmetal laminates the bonding of cermets to the hardmetals and that of mixtures 50% hardmetal + 50% cermet, 33% hardmetal + 66% cermet and 66% hardmetal + 33% hardmetal to cermet or hardmetal, respectively, is tight and gapless in most cases. No major distortion or bending is observed although the shrinkage of each of the alloys is quite different. With some combinations a clearly visible graded diffusion zone forms, partially with microstructures different from the starting material.

Laminates, Cermets, Hardmetals, Interface microstructure, gradient zone