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

作　　者：Shu-na CHEN Hengzhong FAN Yunfeng SU Jicheng LI Junjie SONG Litian HU Yongsheng ZHANG 

机构地区：[1]State Key Laboratory of Solid Lubrication,Lanzhou Institute of Chemical Physics,Chinese Academy of Sciences,Lanzhou 730000,China [2]Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Journal of Advanced Ceramics》2022年第9期1391-1403,共13页先进陶瓷（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant No.52005486);the Science and Technology Planning Project of Chengguan District of Lanzhou City(Grant No.2021JSCX0030);the Major National R&D Projects(Grant No.J2019-IV-0020-0088)。

摘　　要：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℃.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℃),owing to the lubrication function of hBN cell boundaries with weak van der Waals forces and a small amount of liquid B_(2)O_(3)produced.As a result,a synergistic improvement of mechanical and tribological properties at high temperature(1000℃)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.

关 键 词：self-lubricating composite ceramic bioinspired structure resistance curve(R-curve) high-temperature property friction and wear 

分 类 号：TQ174[化学工程—陶瓷工业]