简介概要

制备工艺对C/C-SiC复合材料滑动摩擦特性的影响

来源期刊:中国有色金属学报2008年第11期

论文作者:易茂中 葛毅成 彭 可 杨芸芸

文章页码:2008 - 2008

关键词:C/C-SiC复合材料;制备工艺;滑动摩擦;摩擦特性

Key words:C/C-SiC composites; fabrication process; sliding friction; tribological behavior

摘    要:分别采用熔渗硅(MSI)、前驱体裂解(PIP)技术制备4种C/C-SiC复合材料。在M2000型实验机上测试材料的摩擦磨损特性。结果表明:采用MSI制备的2种C/C-SiC摩擦因数高、不稳定,摩擦因数在0.404~0.906之间波动;随载荷增加,MSI-SiC质量分数为40.9%的材料B的摩擦因数变化幅度低于SiC质量分数18.9%的材料A的摩擦因数,但其随时间延长的波动幅度大;随时间延长和载荷增加,采用PIP制备的2种C/C-SiC材料的摩擦因数变化小,在0.08~0.14之间波动;其中,随载荷增加,PIP-SiC质量分数为18.0%的材料C的摩擦因数波动幅度稍大于SiC质量分数为6.0%的材料D的。EDAX分析表明:材料A的部分磨损表面未发现碳元素;而材料C磨损表面的碳硅摩尔比大于1,使其有足够的炭形成自润滑膜,从而降低材料的摩擦因数。SEM形貌表明:MSI技术制备的材料摩擦表面粗糙,未形成完整的摩擦膜,而采用PIP技术制备的材料摩擦表面较完整且致密。

Abstract: Four C/C-SiC composites were prepared using molten-Si infiltration-reaction(MSI) or precursor- pyrolysis(PIP), respectively. The sliding tribological behaviors of these four composites and one C/C composite were tested by M2000 wear tester. The results show that the coefficients of friction (COF) of the two kinds of MSI-composites are high under the applied loads and time, which fluctuate in 0.404~0.906. With increasing loads the COF of composite B with 40.9% (mass fraction) MSI-SiC has lower fluctuation than those of composite A with 18.9% MSI-SiC. But with prolonging time, the COF of composites A has larger changing extent than those of composite B except that under 150N. For the two PIP-composites, the COF are low and stable, which fluctuate in 0.08~0.144. But with increasing load, composite C with 18.0% PIP-SiC has a little larger changing extent than composite D with 6.0% PIP-SiC. The EDAX results show that the carbon element has not been found on part of the worn surface of composite B. The molar ratio of carbon to silicon on the worn surface of composite C is higher than 1, which indicates that carbon friction film can easily form with good lubrication to decrease the COF. SEM images of the MSI-composites have very rough friction films while the PIP-composites have smooth and integrated ones.

基金信息:国家重大基础研究发展计划资助项目



详情信息展示

文章编号:1004-0609(2008)11-2008-06

制备工艺对C/C-SiC复合材料滑动摩擦特性的影响

葛毅成,易茂中,彭  可,杨芸芸

(中南大学 粉末冶金国家重点实验室,长沙 410083)

 

摘  要:分别采用熔渗硅(MSI)、前驱体裂解(PIP)技术制备4种C/C-SiC复合材料。在M2000型实验机上测试材料的摩擦磨损特性。结果表明:采用MSI制备的2种C/C-SiC摩擦因数高、不稳定,摩擦因数在0.404~0.906之间波动;随载荷增加,MSI-SiC质量分数为40.9%的材料B的摩擦因数变化幅度低于SiC质量分数18.9%的材料A的摩擦因数,但其随时间延长的波动幅度大;随时间延长和载荷增加,采用PIP制备的2种C/C-SiC材料的摩擦因数变化小,在0.08~0.14之间波动;其中,随载荷增加,PIP-SiC质量分数为18.0%的材料C的摩擦因数波动幅度稍大于SiC质量分数为6.0%的材料D的。EDAX分析表明:材料A的部分磨损表面未发现碳元素;而材料C磨损表面的碳硅摩尔比大于1,使其有足够的炭形成自润滑膜,从而降低材料的摩擦因数。SEM形貌表明:MSI技术制备的材料摩擦表面粗糙,未形成完整的摩擦膜,而采用PIP技术制备的材料摩擦表面较完整且致密。

关键词:C/C-SiC复合材料;制备工艺;滑动摩擦;摩擦特性

中图分类号:TB332;TH145.1       文献标识码:A

Influence of fabrication of SiC on tribological behavior of  C/C-SiC composite against 40Cr steel

GE Yi-cheng, YI Mao-zhong, PENG Ke, YANG Yun-yun

(State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China)

 

Abstract: Four C/C-SiC composites were prepared using molten-Si infiltration-reaction(MSI) or precursor- pyrolysis(PIP), respectively. The sliding tribological behaviors of these four composites and one C/C composite were tested by M2000 wear tester. The results show that the coefficients of friction (COF) of the two kinds of MSI-composites are high under the applied loads and time, which fluctuate in 0.404?0.906. With increasing loads the COF of composite B with 40.9% (mass fraction) MSI-SiC has lower fluctuation than those of composite A with 18.9% MSI-SiC. But with prolonging time, the COF of composites A has larger changing extent than those of composite B except that under 150N. For the two PIP-composites, the COF are low and stable, which fluctuate in 0.08?0.144. But with increasing load, composite C with 18.0% PIP-SiC has a little larger changing extent than composite D with 6.0% PIP-SiC. The EDAX results show that the carbon element has not been found on part of the worn surface of composite B. The molar ratio of carbon to silicon on the worn surface of composite C is higher than 1, which indicates that carbon friction film can easily form with good lubrication to decrease the COF. SEM images of the MSI-composites have very rough friction films while the PIP-composites have smooth and integrated ones.

Key words: C/C-SiC composites; fabrication process; sliding friction; tribological behavior

                     


炭纤维增强炭基体复合材料(C/C)具有密度低、比强度和比模量高、热导率高、热容大,优异的摩擦特性以及可设计性好等特点,已经在航空航天领域,尤其是高能摩擦领域得到广泛的应用[1?4]。目前,为拓展C/C复合材料的应用领域,克服其易氧化的技术缺陷,在其内添加基体改性剂已成为新的热点。如用SiC改性的C/C-SiC复合材料已被广泛用在F1方程式赛车、高性能飞机以及重载车辆的摩擦副上[5?9]

目前,制备C/C-SiC复合材料的主要技术手段是模压、熔渗以及前驱体浸渍裂解技术(PIP)等[10?13]。其中采用炭纤维、石墨粉、Si粉以及树脂模压炭化技术制备的C/C-SiC材料强度低[10],难以满足现代高能摩擦领域的应用需求。采用熔渗Si技术制备的C/C-SiC增密速度快,但易形成大块未反应的Si,影响材料的性能[11?12];而采用PIP技术制备的C/C-SiC的原料昂贵、增密速度慢也限制其应用[13]。因此,针对特定的应用需求,在上述3种技术中选用合理的方法,制备相应的C/C-SiC将是此类材料发展的关键。

相对炭材料,SiC硬度高,无自润滑能力,在C/C-SiC的摩擦过程中易形成硬质相颗粒,影响材料磨损表面的稳定性。因此,SiC在C/C-SiC材料的存在形式、质量分数是影响其性能、尤其是摩擦特性的关键因素,必须加以研究。本文作者研究不同技术制备的SiC对C/C-SiC材料摩擦特性的影响及机理。

1  实验

采用聚丙烯腈炭纤维无纬布/炭毡混合叠层针刺毡坯体作为增强相,采用化学气相渗透技术(CVI)制备C/C复合坯体。之后分别采用前驱体浸渍裂解反应技术(PIP),熔渗硅反应技术(MSI)在C/C坯体中制备SiC,并最终制备出4种C/C-SiC复合材料。为进行对比研究,选用一种基体炭为光滑层热解炭+树脂炭的C/C复合材料进行摩擦实验。5种材料的性能参数列于表1。材料A和B的XRD半定量分析结果见表2。由表可见,由于半定量检测的技术缺陷,材料A和B的成分分布与表1有较大出入,但总体上材料B内的SiC和单质Si质量分数均高于材料A。材料C和D中的采用PIP技术制备的为β-SiC[14]

表1  C/C-SiC和C/C复合材料部分性能参数

Table 1  Properties of C/C-SiC and C/C composites

表2  材料A和B的XRD半定量分析结果

Table 2  XRD results of compounds A and B

将材料加工成20 mm×12 mm×6 mm的块状试样,用金相砂纸研磨、清洗后备用,材料表面粗糙度为0.8 ?m。在M2000型摩擦实验机上测试其环?块滑动摩擦行为。对偶为40Cr钢,其尺寸为d1 40 mm×d2 16 mm×10 mm。载荷分别为60、80、100、120和150 N。每次摩擦时间为5 h,干态、室温。配副间线速度为0.42 m/s。每组实验重复3次,取其摩擦因数平均值。

采用SEM观察磨损表面形貌、EDAX分析磨损表面成分变化。

2  实验结果

图1所示为实验5 h后4种C/C-SiC复合材料摩擦因数与C/C复合材料的对比。由图1可见,随载荷增加,除材料B的摩擦因数有所波动外,其余材料的基本为下降趋势。其中材料C、D和C/C复合材料的摩擦因数均比材料A和B低且稳定。

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