Abstract To date, surprisingly few studies about the structure-property correlations in porous B4C ceramics with unidirectionally aligned channels have been reported. In this study, bimodally lamellar porous B4C ceramics aligned along the freezing direction were produced via freeze casting method using Al2O3–Y2O3 as the sintering additive. The porosity, pore size distribution, morphology, and compressive strength could be effectively tailored by the addition of Al2O3–Y2O3. The volume shrinkage ranged from 1.66 to 2.42%, much lower than the reported values of porous ceramics. A low-melting eutectic liquid was observed to exert significant effects on the sintering and strength of the porous B4C ceramics. By varying the contents of the Al2O3–Y2O3 sintering additive, the preforms displayed a rather high porosity of 78.71–82.01%, a low closed porosity of 0.37–0.86% and an excellent compressive strength of 1.76–3.28 MPa. Meanwhile, the wavelength, lamellar thickness, and pore diameter decreased as the Al2O3–Y2O3 content increased. Adding Al2O3–Y2O3 can tailor the structures of porous B4C ceramics prepared by freeze casting, which is of great significance for the preforms with low shrinkage, low density, high porosity, and satisfactory mechanical performance.

中文翻译：

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使用烧结添加剂控制具有单向排列通道的多孔 B4C 陶瓷的结构和机械性能

摘要 迄今为止，令人惊讶的是，关于具有单向排列通道的多孔 B4C 陶瓷的结构-性能相关性的研究报告很少。在这项研究中，使用 Al2O3-Y2O3 作为烧结添加剂，通过冷冻铸造方法生产了沿冷冻方向排列的双峰层状多孔 B4C 陶瓷。通过添加 Al2O3-Y2O3 可以有效地调整孔隙率、孔径分布、形态和抗压强度。体积收缩率为 1.66% 至 2.42%，远低于多孔陶瓷的报道值。观察到低熔点共晶液体对多孔 B4C 陶瓷的烧结和强度产生显着影响。通过改变 Al2O3–Y2O3 烧结添加剂的含量，预制件显示出 78.71–82.01% 的相当高的孔隙率，0.37-0.86% 的低封闭孔隙率和 1.76-3.28 MPa 的优异抗压强度。同时，随着 Al2O3-Y2O3 含量的增加，波长、层状厚度和孔径减小。添加Al2O3-Y2O3可以定制冷冻铸造制备的多孔B4C陶瓷的结构，这对于制备低收缩、低密度、高孔隙率和令人满意的机械性能的预制件具有重要意义。