C/C多孔体的高温热处理对C/C-SiC复合材料摩擦磨损行为的影响  

Influence of High Temperature Treatment of C/C Porous Preform on Friction and Wear Behavior of C/C-SiC Composites

作　　者：张硕 付前刚[1] 张佩 费杰[1] 李伟[1] ZHANG Shuo;FU Qiangang;ZHANG Pei;FEI Jie;LI Wei(State Key Laboratory of Solidification Processing,Shaanxi Key Laboratory of Fiber Reinforced Light Composite Materials,Northwestern Polytechnical University,Xi’an 710072,China)

机构地区：[1]西北工业大学凝固技术国家重点实验室,纤维增强轻质复合材料陕西省重点实验室,西安710072

出　　处：《无机材料学报》2023年第5期561-568,共8页Journal of Inorganic Materials

基　　金：国家自然科学基金(52125203,51872239);国家重点研发计划(2021YFA0715800);基础科学中心燃气轮机项目(P2021-A-Ⅳ-003-001)。

摘　　要：低密度C/C多孔体的结构与性能调控是制备具有优异摩擦磨损性能的C/C-SiC复合材料的关键。本研究采用化学气相渗积法制备了C/C多孔体,并对其进行2100℃高温热处理,再通过反应熔渗法制备了C/C-SiC复合材料,研究了C/C多孔体高温热处理对C/C-SiC复合材料微观结构、导热性能和摩擦磨损性能的影响。结果表明,经2100℃热处理的C/C多孔体孔隙率和石墨化程度增加,用其制备的C/C-SiC复合材料比C/C多孔体未经热处理的密度更大(2.22 g/cm^(3)),孔隙率由5.1%降低至3.4%, SiC陶瓷相含量比热处理前提高11.9%。石墨化程度越高,声子的平均自由程越大,因此其室温的导热率提升到3.1倍, 1200℃导热率提升到1.2倍。经过热处理的热解炭更软,摩擦面易形成连续且稳定的摩擦膜,因此摩擦系数更稳定,并且在测试载荷为3、6和9 N下磨损率均显著降低,下降幅度达到47.8%、41.9%和11.7%,平均摩擦系数分别为0.47、0.38和0.39。综上所述,对C/C多孔体进行高温热处理可使C/C-SiC复合材料的导热性能提升,更耐磨并且表现出更稳定的摩擦系数。Controlling the structure and properties of low-density C/C porous preforms is the key to the preparation of C/C-SiC composites with excellent friction and wear properties.In this study,C/C porous preforms prepared by chemical vapor infiltration were subjected to high temperature heat-treatment at 2100℃.C/C-SiC composites were prepared by reactive melt infiltration.Effects of high temperature heat-treatment of C/C porous preforms on microstructures,thermal properties and tribological properties of C/C-SiC composites were investigated.The results showed that the porosity and graphitization degree of the C/C porous performs increased after high temperature heat-treatment at 2100℃.The C/C-SiC composites have a higher density(2.22 g/cm^(3)),and the porosity is reduced from 5.1%to 3.4%,the phase content of SiC ceramic is increased by 11.9%.The mean free path of phonons is larger when C/C porous preforms have a higher degree of graphitization,resulting in thermal conductivity at room temperature being increased by 2.1 times,and the thermal conductivity at 1200℃being increased by 0.2 times.Wear surface of C/C-SiC composites forms a continuous and stable friction film,which is attributed to the fact that the PyC after high temperature treatment is softer and easier to be extruded into a film.Thus,the friction coefficient is more stable,and the wear rate is reduced under the test loads of 3,6 and 9 N,by 47.8%,41.9%and 11.7%,and the average friction coefficients are 0.47,0.38 and 0.39,respectively.Therefore,high temperature heat-treatment of the C/C porous preforms can improve the thermal conductivity of the C/C-SiC composites,which exhibits a more stable friction coefficient and more wear-resistant.

关 键 词：C/C-SIC复合材料 高温热处理 导热率 摩擦 耐磨 

分 类 号：TB332[一般工业技术—材料科学与工程]