Methylhydridopolysilazane and its Pyrolytic Conversion to Si3N4/SiC Ceramics

Abstract

The present report explores the use of liquid state nuclear magnetic resonance (NMR) spectroscopy for characterizing the methylhydridopolysilazane (MHPS) prepared by the Seyferth/Wiseman procedure and compares the structure of this polymer with other ceramic precursors derived from similar synthetic routes. X-ray diffraction, cross-polymerization (CP) and single-pulse magic angle spinning (MAS) solid state NMR spectroscopy were employed for characterizing temperature-induced short range bonding and phase evolution in MHPS precursors to SiC/Si3N4 ceramics. The molecular weight and methyl substitution of the preceramic polymers is shown to affect the ceramic yield and phase development of these polysilazanes during pyrolysis. Ceramic yields approaching 90% are observed in these systems. CPMAS-NMR is shown to be uniquely capable of identifying the hydrogen-rich environments and the onset of short range SiC and SiN phase development in these amorphous preceramic materials.

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Document Details

Document Type
Technical Report
Publication Date
Apr 20, 1993
Accession Number
ADA264150

Entities

People

  • Anthony J. Perrotta
  • Carsten Strohmann
  • Neal R. Dando
  • Regina M. Stewart

Organizations

  • Massachusetts Institute of Technology

Tags

Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Ceramic Materials
  • Ceramic Matrix Composites
  • Chemistry
  • Diffraction
  • Magnetic Resonance
  • Materials
  • Materials Processing
  • Materials Science
  • Molecular Weight
  • Nitrogen Compounds
  • Nuclear Magnetic Resonance
  • Resonance
  • Silicon Carbide
  • Spectra
  • Spectroscopy
  • X Rays
  • X-Ray Diffraction

Fields of Study

  • Materials science

Readers

  • Combustion science or combustion engineering.
  • Polymer Science and Technology
  • Reinforced Composite Materials