Formation of nanocrystalline titanium carbonitride by pyrolysis of poly(titanylcarbodiimide)

Abstract

The chemical formation of advanced ceramics from organometallic precursors is promising with respect to structural design and tailormade properties. We report on the synthesis of nanocrystalline titanium carbonitride materials at different pyrolysis temperatures via the polymer-to-ceramic transformation of synthesised poly(titanylcarbodiimides) and their structural and nanochemical characterization using high-resolution and analytical electron microscopy, in combination with quantummechanical calculations. Pyrolysis at 800 • C leads to a mixture of amorphous carbon and titanium nitride as crystalline particles of about 4 nm in size. Pyrolysis at 1100 • C yields titanium carbonitride as crystalline particles of 20-30 nm in size. The identification of all phases was possible by the analysis of the measured energy-loss near-edge spectra of their C-K and N-K edges, and comparison with measured standards and with simulated fine structures using calculations based on the density functional theory.

Reaction sequences and influence factors during preparation of Ti(C,N) powders

“…Regrettingly, only commercial submicrometric (0.5-2 m) powders are available nowadays on the market [2]. Recently, approaches synthesizing ultrafine or nano-Ti(C,N) powders have been developed include hydrogen plasma [3], mechanical alloying (MA) [4][5][6], sol-gel [7], low temperature chemical [8],carburization of TiN [9], pyrolysis of poly(titanylcarbodiimide) [10]. However, synthesis methods of ultrafine or nano-Ti(C,N) are not well established and relevant studies are still rare [5].…”

Macroporous SiCMoSi2ceramics from templated hybrid MoCl5–polymethylsilane

“…In addition, many groups have also reported the synthesis of zirconium-or titanium-containing polymers that displayed an enhanced electrical conductivity or unique magnetic behavior. 17,18 However, there have been few reports about molybdenum-containing non-oxide ceramics from polymeric routes, although it is well known that SiC-MoSi 2 composites can be used as high-temperature structural materials and heating elements owing to their many novel properties, such as high creep resistance, high oxidation resistance at elevated temperature, high heat conductivity and high electrical conductivity.…”

Mechanically induced self-propagating reaction of vanadium carbonitride

“…The composition x¼ 0.25 has a spectrum with the peak at 286 eV and a higher intensity peak at 296 eV; according to the literature [41][42][43], this behavior indicates the presence of amorphous carbon or a nitride with the amorphous carbon on a grain boundary. However, this composition is obtained by a diffusion mechanism, and more milling time was required.…”

“…4 shows the nitrogen and C K-edges for the different prepared samples. The data in the literature for such compounds, particularly titanium carbonitride [41][42][43], show that the carbon K-edge of a carbide is identified by two peaks centered at approximately 283 eV (π bond) and 292 eV (σ bond), in which the first is of higher intensity than the second; the free amorphous carbon is identified by a peak at 285.6 eV and a broader and higher intensity peak at 296 eV. Finally, the carbonitride presents the same peaks as the carbide, 283 eV and 292 eV, but in this case, the second peak was slightly more intense than the first peak because of the inverse relationship for the orbital occupation density involved with respect to the carbide.…”