Abstract
Pressureless sintering of boron carbide ceramics containing 0-25 vol. % TiB2 phase, produced via an in-situ chemical reaction between B4C, TiO2, and elemental carbon, was studied in the isothermal and constant-heating-rate regimes. The presence of TiB2 results in a decrease in activation energy for sintering from 717 kJ/mol at 0 vol. % TiB2 to 266 kJ/mol at 25 vol. % TiB2. Ceramic bodies of B4C ― TiB2 particulate composites with relative densities of up to 99% were sintered without pressure at temperatures of 2050-2100°C. Grain boundary diffusion is the primary mechanism of TiB2 particle coarsening. TiB2 particle size is bimodal depending on whether the particle is confined within a B4C grain or located on the grain boundary. Densification behavior of the B4C ― TiB2 system is identical at different heating rates in the temperature range of 1800-2150°C.
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Skorokhod, V.V. Processing, Microstructure, and Mechanical Properties of B4C ― TiB2 Particulate Sintered Composites. Part I. Pressureless Sintering and Microstructure Evolution. Powder Metallurgy and Metal Ceramics 39, 414–423 (2000). https://doi.org/10.1023/A:1026625909365
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DOI: https://doi.org/10.1023/A:1026625909365