Bioinspired PcBN/hBN fibrous monolithic ceramic: High-temperature crack resistance responses and self-lubricating performances
Bioinspired PcBN/hBN fibrous monolithic ceramic: High-temperature crack resistance responses and self-lubricating performances
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DOI：
10.1007/s40145-022-0618-y
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发表时间：
2022-08
影响因子：
16.9
通讯作者：
Shu-na Chen;Hengzhong Fan;Yunfeng Su;Ji-chao Li;Junjie Song;Litian Hu;Yongsheng Zhang
中科院分区：
文献类型：
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作者：
Shu-na Chen;Hengzhong Fan;Yunfeng Su;Ji-chao Li;Junjie Song;Litian Hu;Yongsheng Zhang
天然材料的高强度和韧性主要是由在不同长度尺度上运行的机制组合决定的，这可以作为降低陶瓷固有脆性的策略。以竹子的结构为灵感，以立方氮化硼/六方氮化硼（PcBN/hBN）纤维为晶界，构建了具有长纤维排列结构的多晶立方氮化硼/六方氮化硼（PcBN/hBN）纤维单片陶瓷，并对其抗裂响应和摩擦学性能进行了研究。复合陶瓷的破坏表现为非脆性破坏，并表现为上升阻力曲线（r曲线）行为，这主要归因于分层结构中的多尺度裂纹效应。最大裂纹扩展韧性极高（约21 MPa·m1/2），比裂纹起裂韧性提高了270%。即使在1000℃以上也能保持优异的抗断裂性能。此外，当复合陶瓷与Si3N4pin在高温（1000℃）下配对时，由于hBN细胞边界具有弱范德华力和少量B2O3液体的润滑作用，复合陶瓷表现出低而稳定的摩擦系数（约0.33）。因此，通过将仿生结构与摩擦学设计相结合，实现了高温（1000℃）下机械性能和摩擦学性能的协同改善。为扩大自润滑复合陶瓷在恶劣环境下的应用提供了重要的理论和技术支持。
The high strength and toughness of natural materials are mainly determined by a combination of mechanisms operating at different length scales, which can be used as a strategy to reduce the intrinsic brittleness of ceramics. Inspired by the architectures of bamboo, the polycrystalline cubic boron nitride/hexagonal boron nitride (PcBN/hBN) fibrous monolithic ceramics with a long fiber arrangement structure was constructed with PcBN fiber cells and hBN cell boundaries, and its crack resistance responses and tribological performances were investigated. The composite ceramic failed in a non-brittle manner with the rising resistance curve (R-curve) behavior, which was attributed to multiscale crack effects in the hierarchical architecture. The maximum crack growth toughness was extremely high (approximately 21 MPa·m1/2), corresponding to a 270% increase over the crack initiation toughness. Excellent fracture resistance could be retained even above 1000 °C. Moreover, the composite ceramic exhibited low and stable friction coefficients (approximately 0.33) when paired with a Si3N4pin at high temperature (1000 °C), owing to the lubrication function of hBN cell boundaries with weak van der Waals forces and a small amount of liquid B2O3 produced. As a result, a synergistic improvement of mechanical and tribological properties at high temperature (1000 °C) was realized by combining bionic structure and tribological design. It provides important theoretical and technical support for expanding the application of self-lubricating composite ceramics in harsh environments.