Magnetic resonance characterization of solid-state intermediates in the generation of ceramics by pyrolysis of hydridopolysilazane

Lewis, R.; Maciel, Gary E.

doi:10.1007/bf01154517

Cited by 23 publications

(11 citation statements)

References 38 publications

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“…It reflects sp 2 carbon and is attributed to the formation of a graphene-like carbon phase. Signals with chemical shifts between 120 and 130 ppm [26][27][28][29][30] or at 140 ppm 31,32 were both reported in the literature, and were assigned to graphene-like phases. Sample S1 behaves differently, since signal components with both chemical shift values are observed simultaneously.…”

Section: Solid-state Nmr Spectroscopymentioning

confidence: 97%

Carbon-rich SiCN ceramics derived from phenyl-containing poly(silylcarbodiimides)

Mera

Riedel

Poli

et al. 2009

Journal of the European Ceramic Society

151

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Section: Solid-state Nmr Spectroscopymentioning

confidence: 97%

Carbon-rich SiCN ceramics derived from phenyl-containing poly(silylcarbodiimides)

Mera

Riedel

Poli

et al. 2009

Journal of the European Ceramic Society

151

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“…13 C, 29 Si, 1 H, 11 B, 15 N, are NMR-active and -apart from 15 N -can be studied without any kind of isotope enrichment of the samples. [16][17][18][19][20][21][22][23][24][25] To our knowledge this is the first comprehensive solidstate NMR study on the thermolysis of polymeric precursors that form Si-B-C-N ceramics. On the basis of our structural assignment, which is further supported by complementary FT IR experiments, ceramization or reaction schemes are proposed that occur during the thermolysis process.…”

Section: Introductionmentioning

confidence: 99%

Solid‐state NMR and FT IR studies of the preparation of Si–B–C–N ceramics from boron‐modified polysilazanes

Schuhmacher

Berger

Weinmann

et al. 2001

Applied Organom Chemis

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N 4Àx units with x = 0, 1, 2). In addition, a considerable amount of hydrogen is present even at this temperature. The NMR studies have further shown that above 1700°C the amorphous ceramic demixes, along with the formation of crystalline silicon nitride and silicon carbide. Likewise, structural changes for BN domains have been registered that are attributed to the formation of turbostratic BN(C) interface layers. In summary, the present study has demonstrated that the combination of multinuclear solid-state NMR and FT IR spectroscopy is a powerful method to probe the thermolytic preparation of ternary and quaternary ceramic materials.

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“…Other studies on the pyrolysis process of SiCN preceramic polymers present 29 Si and 13 C MAS NMR spectra with varying degrees of completeness in their interpretation . In contrast, relatively few reports have shown 15 N MAS NMR spectra mainly because of the low sensitivity of this nucleus in natural abundance (even if the CP sequence is used). Recently, the IRCP sequence was successfully extended to this isotope in different reference compounds containing various NH x sites (0≤ x ≤ 4) .…”

Section: Introductionmentioning

confidence: 99%

Thermal Decomposition of Poly(methylsilsesquicarbodiimide) to Amorphous Si−C−N Ceramics

Gabriel¹,

Riedel²,

Dreßler³

et al. 1999

Chem. Mater.

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This paper is based on the recent discovery that the thermal decomposition of poly(methylsilsesquicarbodiimide), [CH3Si(NCN)1.5] n , leads to amorphous silicon carbonitride (SiCN) ceramics. In the present study the polymer-to-ceramic transformation is characterized using analytical and spectroscopic methods. In particular, the structural transition from the molecular precursor to the final amorphous SiCN ceramic was studied by solid-state NMR spectroscopy. The coordination of the silicon atoms changes from CH3−Si(−NCN−)3 in the polysilylcarbodiimide precursor at room temperature to Si(−N<)4 in the X-ray amorphous reaction product formed at 1200 °C. This result implies the formation of amorphous silicon nitride (Si3N4). The remaining weight fraction is analyzed to be elemental carbon. According to bulk chemical analysis, the poly(methylsilsesquicarbodiimide)-derived SiCN is comprised of a mixture of 1 mol amorphous Si3N4 with 3 mol amorphous carbon. The molar ratio Si3N4/C = 1/3 is suitable for the formation of stoichiometric silicon carbide, which is expected thermodynamically at temperatures exceeding 1440 °C in 0.1 MPa N2. The pyrolysis behavior of the poly(silylcarbodiimide) and the formation of silicon carbonitride ceramics are compared to those of poly(silazanes).

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Magnetic resonance characterization of solid-state intermediates in the generation of ceramics by pyrolysis of hydridopolysilazane

Cited by 23 publications

References 38 publications

Carbon-rich SiCN ceramics derived from phenyl-containing poly(silylcarbodiimides)

Carbon-rich SiCN ceramics derived from phenyl-containing poly(silylcarbodiimides)

Solid‐state NMR and FT IR studies of the preparation of Si–B–C–N ceramics from boron‐modified polysilazanes

Thermal Decomposition of Poly(methylsilsesquicarbodiimide) to Amorphous Si−C−N Ceramics

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Magnetic resonance characterization of solid-state intermediates in the generation of ceramics by pyrolysis of hydridopolysilazane

Cited by 23 publications

References 38 publications

Carbon-rich SiCN ceramics derived from phenyl-containing poly(silylcarbodiimides)

Carbon-rich SiCN ceramics derived from phenyl-containing poly(silylcarbodiimides)

Solid‐state NMR and FT IR studies of the preparation of Si–B–C–N ceramics from ­boron‐modified polysilazanes

Thermal Decomposition of Poly(methylsilsesquicarbodiimide) to Amorphous Si−C−N Ceramics

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Solid‐state NMR and FT IR studies of the preparation of Si–B–C–N ceramics from boron‐modified polysilazanes