Fabrication of tungsten carbide foam through gel-casting process using nontoxic sodium alginate

•Sodium alginate, a natural innoxious polymer, was employed for gel-casting process.•The gel was loaded by high density tungsten carbide powder.•Drying the slurry led to microporous foam with 50–60% porosity.•The dried green bodies exhibit homogenous pore distribution.•Pre-sintered bodies show microporous foams with average pore size of 0.75 μm.

In this study, nontoxic sodium alginate was utilized in gel-casting process to fabricate tungsten carbide (WC) micro-porous foam. Suspensions containing 20 and 25 vol.% WC and 1 wt.% sodium alginate were used. Calcium phosphate and sodium hexa-metaphoshphate were employed as solidifier agent and chelator, respectively. The green bodies were dried at room temperature for 36 h and pre-sintered at 1450 °C for 4 h. The influence of chelator and calcium salt on strength of dried green body was evaluated. Tungsten carbide foams with 50–60% porosity were successfully produced. SEM micrographs of tungsten carbide foams show a uniform porous microstructure, with average size of 0.75 μm.

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