文摘
Kinetic features and the contact interaction mechanism of hot-pressed (residual porosity <3%) of titanium carbonitride samples of various compositions with the Ni–25% Mo melt (t = 1400–1500°C, τ = 0.1–25 h) are investigated by electron-probe microanalysis. It is established that the dissolution rate of the interstitial refractory phase (IRP) in the Ni–Mo melt lowers in a series TiC–TiC0.7N0.3–TiC0.5N0.5, while the degree of process incongruence rises. The composition of intermediate interaction products varies correspondingly. The peculiarities of formation of the most important phase component of the TiCN cermets—K-phase of the Ti1–nMonCx composition—are revealed. It is proven by the local mass spectrometry method that the K-phase has a carbide nature. It is also established that it is formed only if the initial titanium carbonitride TiC1–xNx is sufficiently enriched with carbon (x ≤ 0.5). It is stated that the K-phase is an actual basis of all cermets with the Ni–Mo binder. Its bulk concentration in alloys exceeds the content of the nominal alloy base by a factor of several times. The chemical substantiation of the selection of titanium carbonitride of the TiC0.5N0.5 composition as an optimal “precursor” of the K-phase, which is formed during liquid-phase sintering of TiCN cermets, is given originally.