Effect of the nickel-chromium binder on the densification kinetics of chromium carbide-titanium nitride cermets in hot pressing

The paper studies the densification kinetics in hot pressing of mixtures with equimass content (50 ∶ 50) of Cr₃C₂ and TiN without a binder at 1350, 1470, and 1800°C under 16.2, 21.6, and 35.7 MPa, a mixture of Cr₃C₂-50 wt.% TiN with 5 wt.% of the Ni-Cr binder at 1300, 1350, and 1370°C under 5 and 10 MPa, and a mixture of Cr₃C₂-50 wt.% TiN with 20 wt.% of the Ni-Cr binder at 1180, 1220, and 1270 °C under 5 and 10 MPa with isothermal holding for up to 25 min. The behavior of materials in hot pressing is analyzed using the viscous flow theory for porous body. It is shown that the compaction of an alloy without a binder and with the Ni-Cr binder in hot pressing is described by a generalized equation of volume viscous flow of a porous body. It is controlled by non-linear creep with an effective activation energy of 3.2 eV in materials without a binder and by a viscous flow in alloys with a metal binder. The structure and mechanical properties of the materials obtained are studied. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 5–6 (455), pp. 29–37, 2007.