Reactive sintering of tungsten-doped high strength ZrB2–SiC porous ceramics using metastable precursors

• Tungsten-doped porous ZrB2–SiC specimens were fabricated by reactive sintering.
• Both sintering and mechanical properties were improved by doping with tungsten.
• Optimum concentration to obtain high mechanical properties was W/Zr (mol) = 0.05.
• Sintering might be promoted by self-accelerated diffusion.
• Mechanical properties might be improved by solid solution strengthening.

Tungsten-doped porous ZrB2-20 vol.% SiC specimens with a high strength skeleton were fabricated by reactive sintering using metastable reactants, i.e., as-synthesized amorphous hydrous ZrO2–WO3/ZrO2, amorphous boron, nanocarbon, and β-SiC. Doping with tungsten clearly promoted sintering and improved mechanical properties; the optimum tungsten concentration to obtain high mechanical properties was investigated. A single-phase solid solution (Zr,W)B2 was formed in the specimens with tungsten. We suggest that sintering was promoted by self-accelerated diffusion owing to the formation of point defects caused by doping with tungsten. The improvement of mechanical properties could be attributed to solid solution strengthening.

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