Titanium carbonitride powder

Bonetti, R. S., et al., CVD of Titanium Carbonitride atModerate Temperature Properties and Applications, Metal Powder... 

An unusual new synthesis method involves carrying out reactions in a molten salt medium, and has been used on an industrial scale for the production of metallic nitride, carbide or carbonitride powders.25 An illustration of this CEREX process is the preparation of oxygen-free titanium nitride in molten calcium chloride. The method involves the reaction between titanium tetrachloride and calcium nitride ... 

The boundary between hardmetals and cermets is not strict because many of these compacts resemble microstructure features of both type of materials [106] faceted WC crystals together with round-shaped titanium carbonitride-based hard particles. Generally, these titaniiun carbonitride hardmetals are comparable with respect to properties and microstructure to WC-based hardmetals. The powders of these materials are liquid phase sintered with Ni or Ni-Co binder metal alloys. The core-and-rim structure of the hard phase usually exhibit a molybdenum- and carbon-rich (Ti,Mo)C rim and a titanium- and nitrogen-rich Ti(C,N) but can also be inverted (compare Fig. 26). The metallurgy of the phase reactions is (because of the complexity of the multicomponent system) not yet fully understood [69]. 

The powder of silicon nitride of the SHS-Az type can contain in the structure from 40% up to 95% (a-nitride phase as anisotropic whiskers by a diameter 1 pm forming wave structure (Figure 8.2)). The particles of the boron nitride powder of the SHS-Az type are ultra fine and have the disc form, and the diameter of disks at 10-15 of time exceeds their thickness having the linear size about 20 nm. The crystal lattice BN has deformations of turbostrate kind with a degree of three-dimensional order 0.40-0.50. The powder of titanium carbonitride with composition TiCggNog of the SHS-Az type differs from similar powders of traditional technologies of synthesis of more branched structure, typical for formation of... 

All precursors are amorphous up to calcination temperatures of around 600°C. At higher temperatures, in most cases powders with extremely small crystallite sizes of around 20-40 nm are formed (Fig. 7). A further increase in calcination temperature promotes crystal growth. With aluminum nitride, a white powder with a low oxygen and carbon content is obtained [97]. Other main group element precursors exhibit fairly different behaviors Mg and Ca precursors yield metal cyanamide [99]. Calcination of the transition element precursors (Fig. 8) results in the formation of nitrides, carbonitrides, or carbides. For the titanium-containing precursors, TiN/TiC solid solutions can be obtained [96] the quantity of carbon strongly depends on the calcination atmosphere applied (argon, 31 wt% ammonia, 5.1 wt%). 

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