烧结助剂对C_(sf)/SiC-BN-ZrC-ZrB_(2)多相陶瓷基复合材料组织性能的影响  

Effect of Sintering Additives on Microstructure and Performance of C_(sf)/SiC-BN-ZrC-ZrB_(2)Multiphase Ceramic Matrix Composites

作　　者：张战胜 张鹏飞[1] 王标[1] ZHANG Zhansheng;ZHANG Pengfei;WANG Biao(School of Materials Science and Engineering,Henan University of Science and Technology,Luoyang 471000,Henan,China)

机构地区：[1]河南科技大学材料科学与工程学院,河南洛阳471000

出　　处：《陶瓷学报》2024年第4期729-738,共10页Journal of Ceramics

基　　金：国家自然科学基金(U1504516)。

摘　　要：在制备C_(sf)/SiC-BN-ZrC-ZrB_(2)多相陶瓷基复合材料时,如何有效促进其烧结致密化过程,同时减少对碳纤维的损伤一直是该复合材料工程应用中面临的一大难题。通过在原料中添加B_(4)C-C_(g)、Al_(2)O_(3)-Y_(2)O_(3)、酚醛树脂等烧结助剂,采用热压工艺制备了C_(sf)/SiC-BN-ZrC-ZrB_(2)复合材料。采用XRD、SEM、EDS、力学性能测试等方法详细研究了烧结助剂类型及含量对复合材料微观组织、力学性能、碳纤维结构等的影响规律。结果表明,添加B_(4)C-C_(g)(2 wt.%)能够在一定程度上缓解碳纤维受到的损伤,复合材料的断裂韧度达7.39 MPa·m^(1/2),且呈现非脆性断裂模式。当B_(4)C-C_(g)的含量为4 wt.%时,过量的烧结助剂无助于复合材料力学性能的继续提高,也无法更加有效地避免碳纤维受到的侵蚀损伤。添加酚醛树脂加大了碳纤维与陶瓷基体之间分散的难度,纤维出现严重的团聚、架桥等现象,致使复合材料力学性能下降。添加Al_(2)O_(3)-Y_(2)O_(3)能显著提高复合材料的弯曲强度(σbb=147.45 MPa),但生成的YAG相对碳纤维侵蚀严重,纤维的拔出长度较短且表面粗糙,复合材料的断裂韧度为6.94 MPa·m^(1/2)。添加B_(4)C-C_(g)可以适当消除陶瓷粉体表面的氧化膜和杂质,促进原子扩散和复合材料致密化,同时能够在一定程度上减轻碳纤维受到的反应侵蚀损伤现象。How to effectively promote the densification of C_(sf)/SiC-BN-ZrC-ZrB_(2)while reducing the damage to carbon fibers has always been a challenge in the application of this composite.In the current work,sintering aids,such as B_(4)C-C_(g),Al_(2)O_(3)-Y_(2)O_(3)and phenolic resin,were used to prepare C_(sf)/SiC-BN-ZrC-ZrB_(2),by using hot pressing process.The influence of sintering aid types and contents on microstructure,mechanical property and carbon fiber structure of the composites was studied by using XRD,SEM,EDS and mechanical property testing.It is found that addition of 2 wt.%B_(4)C-C_(g)reduced the damage of carbon fibers to a certain extent.The composite possessed a fracture toughness of 7.39 MPa·m^(1/2),with non-brittle fracture mode.When the content of B_(4)C-C_(g)was increased to 4 wt.%,the effect of sintering aid on mechanical properties was leveled off,while erosion of carbon fibers cannot be further reduced.The addition of phenolic resin hindered the dispersion between fibers and the ceramic matrix,thus leading to serious fiber aggregation and property degradation.The addition of Al_(2)O_(3)-Y_(2)O_(3)improved the bending strength of the composite(σ_(bb)=147.45 MPa).However,the YAG severely corroded the carbon fibers,resulting in short pulling-out length and rough surface for the fibers,while the fracture toughness was decreased to 6.94 MPa·m^(1/2).In conclusion,B_(4)C-C_(g)is helpful to remove the oxide films and impurities on the surface of ceramic powders,which promoted the atomic diffusion and the densification of the composite and also reduced the erosion of the carbon fibers.

关 键 词：陶瓷基复合材料 纤维损伤 烧结助剂 力学性能 界面反应 

分 类 号：TQ174.75[化学工程—陶瓷工业]