Bioinspired PcBN/hBN fibrous monolithic ceramic: High-temperature crack resistance responses and self-lubricating performances

• Published in: Journal of advanced ceramics 2022-09, Vol.11 (9), p.1391-1403
• Main Authors: Chen, Shu-na, Fan, Hengzhong, Su, Yunfeng, Li, Jicheng, Song, Junjie, Hu, Litian, Zhang, Yongsheng
• Format: Article
• Language: English
• Subjects: bioinspired structure; Boron nitride; Ceramic materials; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; friction and wear; Glass; high-temperature property; Materials Science; Nanotechnology; Natural Materials; Research Article; resistance curve (R-curve); self-lubricating composite ceramic; Structural Materials; Tribology
• ISSN: 2226-4108; 2227-8508
• DOI: 10.1007/s40145-022-0618-y

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·m 1/2 ), 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 Si 3 N 4 pin 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.