Nanocrystalline Processing and Interface Engineering of Si3N4-based Nanocomposites
Progress rept. 1 Jul-30 Sep 97
MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMICAL ENGINEERING
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This report describes the microstructural characterization of nanocrystalline titanium nitride TiN produced in our forced flow reactor. Microscopy studies of TiN densified through a pressureless sintering process show a consistent ultrafine microstructure with grains of 140 nm and no glassy intergranular or secondary phases. Comparison of TiN ceramics processed by different methods demonstrates that there is a clear benefit to avoiding exposure of the starting powders to air, but that pressure application during sintering e.g., by HIPing at 200 MPa was not necessary to achieve full densification at 1400 deg C. STEM analysis of a fully-dense UN800 TiN ceramic found no oxygen-rich regions in the grains or grain boundaries.
- Industrial Chemistry and Chemical Processing
- Ceramics, Refractories and Glass