Microstructure, oxidation and thermal shock resistance of graphene reinforced SiBCN ceramics
Microstructure, oxidation and thermal shock resistance of graphene reinforced SiBCN ceramics
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DOI：
10.1016/j.ceramint.2015.11.127
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发表时间：
2016-02
影响因子：
5.2
通讯作者：
Daxin Li;Zhihua Yang;D. Jia;Daoxiong Wu;Qishuai Zhu;B. Liang;Shengjin Wang;Yu Zhou
中科院分区：
文献类型：
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作者：
Daxin Li;Zhihua Yang;D. Jia;Daoxiong Wu;Qishuai Zhu;B. Liang;Shengjin Wang;Yu Zhou
采用不同体积的石墨烯片（gpl）作为纳米填料制备了SiBCN陶瓷。研究了纳米填料对烧结陶瓷微观结构、抗氧化性和抗热震性的影响。所有陶瓷的相组成和微观结构都非常相似，主要由β-SiC、BNC和少量α-SiC组成，在基体中相对均匀地分布着5 ~ 10 nm厚的GPLs。以石墨烯为纳米填料的SiBCN陶瓷在1500℃时形成多孔氧化层，厚度测量方法显示氧化行为呈线性动力学。加热过程中的气体演化导致被动氧化行为和重量损失。石墨烯增强SiBCN陶瓷的抗热震性能优于相同材料的整体材料。分布在SiBCN基体中的石墨烯可以耗散裂纹扩展的能量，起到抑制裂纹的作用。石墨烯提供的增韧机制，包括拔出和桥接，似乎有助于改善热冲击效应。此外，致密的氧化表面层的存在阻碍了氧气向内部基体的扩散，并愈合了表面的孔隙和裂纹，这也有助于抗热震性。
SiBCN ceramics were prepared using various volumes of graphene platelets (GPLs) as nanofiller. The effects of the nanofiller on microstructure, and oxidation and thermal shock resistance of as-sintered ceramics were investigated. The phase composition and microstructures were very similar for all investigated ceramics consisting primarily of β-SiC, BNC and small amounts of α-SiC with relatively homogeneously distributed 5–10 nm thick GPLs in the matrix. For SiBCN ceramics incorporating graphene as nanofiller, a porous oxide layer forms at 1500 °C and the oxidation behavior shows a linear kinetics by thickness measurement method. Gas evolution during heating lead to a passive oxidation behavior and weight loss. Graphene reinforced SiBCN ceramics exhibit thermal shock resistance superior to monoliths of the same material. The graphene distributed in SiBCN matrix can dissipate the energy of crack growth and acts as a stopper to cracks. The toughening mechanisms offered by graphene, including pull-out and bridging appear to aid in ameliorating thermal shock effects. Furthermore, the existence of a dense oxide surface layer retards oxygen diffusion into the inner matrix and heals surface pores and cracks, which also contributes to thermal shock resistance.