Synthesis of polymeric precursors for the formation of nanocrystalline Ti-C-N/amorphous Si-C-N composites

The synthesis of trimethylsilyl-substituted poly(titaniumcarbodiimide) as a novel precursor for titanium carbonitride based ceramic materials is described. The precursor and the subsequent processing steps (cross-linking and pyrolysis) are characterized by IR and Raman spectroscopy, thermal gravimetric analysis and simultaneous mass spectroscopy, electron microscopy and powder X-ray diffraction measurements. The novel polymer is formed by the reaction of TiCl4 or Ti(NEt2)4 with bis(trimethylsilyl)carbodiimide. Subsequent pyrolysis at 1000 °C in argon results in the formation of a ceramic composite material consisting of nanocrystalline TiCN and amorphous SiCN as constituting phases. Using Ti(NEt2)4 as a starting reagent instead of TiCl4, chlorine contamination of the ceramic material can be avoided. The different molecular vibration modes of the metal–nitrogen, metal–carbon and nitrogen–carbon bonds in poly(titaniumcarbodiimides) with trimethylsilyl substituents were calculated using quantum mechanical methods, providing a comprehensive understanding of the measured spectra. Copyright © 2001 John Wiley & Sons, Ltd.

[1]  S. Vepřek,et al.  Recent progress in the superhard nanocrystalline composites : towards their industrialization and understanding of the origin of the superhardness , 1998 .

[2]  R. Riedel,et al.  Inorganic solid-state chemistry with main group element carbodiimides , 1998 .

[3]  Hartmut Fuess,et al.  The First Crystalline Solids in the Ternary Si‐C‐N System , 1997 .

[4]  H. Fuess,et al.  Synthese der ersten kristallinen Feststoffe im ternären Si‐C‐N‐System , 1997 .

[5]  M. Jansen,et al.  Novel High‐Performance Ceramics—Amorphous Inorganic Networks from Molecular Precursors , 1997 .

[6]  R. Riedel,et al.  Preparation of Non-Oxidic Silicon Ceramics by an Anhydrous Sol–Gel Process† , 1997 .

[7]  M. Jansen,et al.  Moderne Hochleistungskeramiken – amorphe anorganische Netzwerke aus molekularen Vorläufern , 1997 .

[8]  A. Gabriel,et al.  Nichtoxidische Silicium-Keramiken ber einen wasserfreien Sol-Gel-Proze , 1997 .

[9]  S. Vepřek,et al.  Novel thermodynamically stable and oxidation resistant superhard coating materials , 1996 .

[10]  R. Riedel,et al.  Chemical formation of ceramics , 1996 .

[11]  J. Pillot,et al.  Comprehensive Chemistry of Polycarbosilanes, Polysilazanes, and Polycarbosilazanes as Precursors of Ceramics , 1995 .

[12]  B. Demczyk,et al.  Preparation of Silicon Nitride‐Titanium Nitride and Titanium‐Titanium Nitride Composites from (CH3)3SiNHTiCl3‐Coated Si3N4 and Ti Particles , 1995 .

[13]  F. Aldinger,et al.  Nanosized SiCN-powder by pyrolysis of highly crosslinked silylcarbodiimide , 1995 .

[14]  M. Herrmann,et al.  Densification, microstructure and properties of Si3N4Ti(C,N) composites , 1993 .

[15]  J. Guilemany,et al.  X-Ray Diffraction Analysis of Titanium Carbonitride 30/70 and 70/30 Solid Solutions , 1992, Powder Diffraction.

[16]  J. Stewart.  Optimization of parameters for semiempirical methods II. Applications , 1989 .

[17]  J. Stewart.  Optimization of parameters for semiempirical methods I. Method , 1989 .

[18]  J. Stewart,et al.  Calculation of vibrational frequencies using molecular trajectories , 1988 .

[19]  David F. Shanno,et al.  An example of numerical nonconvergence of a variable-metric method , 1985 .

[20]  R. Rice,et al.  Ceramics Via Polymer Pyrolysisdagger , 1984 .

[21]  K. Okamura,et al.  STRUCTURAL ANALYSIS IN CONTINUOUS SILICON CARBIDE FIBER OF HIGH TENSILE STRENGTH , 1975 .

[22]  D. C. Bradley,et al.  METALLO-ORGANIC COMPOUNDS CONTAINING METAL–NITROGEN BONDS: PART IV. SOME BIS-(PRIMARY AMINO)-TITANIUM COMPOUNDS , 1963 .

[23]  D. C. Bradley,et al.  765. Metallo-organic compounds containing metal–nitrogen bonds. Part I. Some dialkylamino-derivatives of titanium and zirconium , 1960 .

[24]  Pol Duwez,et al.  Phase Relationships in the Binary Systems of Nitrides and Carbides of Zirconium, Columbium, Titanium, and Vanadium , 1950 .