Abstract Complex shaped boron carbide with carbon (B4C/C) at near-full densities were achieved for the first time using negative additive manufacturing techniques via gelcasting. Negative additive manufacturing involves 3D printing of sacrificial molds used for casting negative copies. B4C powder distributions and rheology of suspensions were optimized to successfully cast complex shapes. In addition to demonstrating scalability of these complex geometries, hierarchically meso-porous structures were also shown to be possible from this technique. Resorcinol-Formaldehyde (RF) polymer was selected as the gelling agent and can also pyrolyze into a carbon aerogel network to act as the sintering aid for B4C. Due to the highly effective distribution of in situ carbon for the B4C matrix, near-full sintered density of 97–98% of theoretical maximum density was achieved.

中文翻译：

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来自负增材制造的复杂形状的碳化硼

摘要 使用负增材制造技术通过凝胶浇铸首次实现了接近全密度的复杂形状的碳化硼 (B4C/C)。负增材制造涉及用于铸造负副本的牺牲模具的 3D 打印。B4C 粉末分布和悬浮液的流变学经过优化以成功铸造复杂的形状。除了展示这些复杂几何形状的可扩展性外，该技术还显示出分层介孔结构是可能的。间苯二酚-甲醛 (RF) 聚合物被选为胶凝剂，也可以热解成碳气凝胶网络，作为 B4C 的烧结助剂。由于 B4C 基质的原位碳的高效分布，