Lu De, Zhuang Lei, Yang Yuhang, Jia Shuhai, Su Lei, Zhang Pengcheng, Qin Yuanbin, Niu Min, Peng Kang, Wang Hongjie
State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
ACS Nano. 2025 May 20;19(19):18313-18321. doi: 10.1021/acsnano.5c00570. Epub 2025 May 7.
Porous silicon carbide (SiC) ceramics are considered promising materials for structural applications under severe conditions. However, the inadequate mechanical strength and fracture toughness restrict their further applications. Here, we report the development of strong and tough porous SiC ceramics with highly cross-linked SiC nanowire networks as reinforcements. To be specific, a hot-pressing technique is used to dramatically increase the cross-linking of SiC nanowire networks, followed by chemical vapor infiltration to coat the nanowires with pyrolytic carbon (PyC) nanolayers, as well as precursor infiltration and pyrolysis to introduce a SiC matrix. The resulting porous ceramics exhibit impressive mechanical performance including a flexural strength of 187 MPa, a compressive strength of 215 MPa, a fracture toughness of 3.4 MPa·m, and an energy absorption capability of 19.2 MJ·m at a relatively high porosity of 43%. The highly cross-linked nanowire networks facilitate multiple strengthening and toughening mechanisms, such as nanowire-induced crack deflection, as well as bridging, interfacial sliding, and pull-out of the nanowires. This work demonstrates a versatile strategy for simultaneously improving the strength and toughness of porous ceramics.
多孔碳化硅（SiC）陶瓷被认为是在苛刻条件下用于结构应用的有前途的材料。然而，其机械强度和断裂韧性不足限制了它们的进一步应用。在此，我们报道了以高度交联的SiC纳米线网络作为增强体的强韧多孔SiC陶瓷的开发。具体而言，采用热压技术显著增加SiC纳米线网络的交联，随后进行化学气相渗透以用热解碳（PyC）纳米层包覆纳米线，以及前驱体渗透和热解以引入SiC基体。所得多孔陶瓷表现出令人印象深刻的机械性能，包括在相对较高的43%孔隙率下具有187 MPa的弯曲强度、215 MPa的抗压强度、3.4 MPa·m的断裂韧性以及19.2 MJ·m的能量吸收能力。高度交联的纳米线网络促进了多种强化和增韧机制，如纳米线引起的裂纹偏转以及纳米线的桥接、界面滑动和拔出。这项工作展示了一种同时提高多孔陶瓷强度和韧性的通用策略。
