hBN含量对Si3N4-hBN复相陶瓷性能和微观结构的影响

利用纳米级粉体经热压烧结制备了Si₃N₄-hBN复相陶瓷, 研究了hBN含量对Si₃N₄-hBN复相陶瓷致密度、力学性能、摩擦学性能、微观结构的影响。用阿基米德排水法、三点弯曲法和维氏压痕法测量材料的致密度、力学性能; 用摩擦磨损试验机测试材料的摩擦学性能; 用XRD、EDAX和SEM、LSCM分析观察材料的物相组成和微观结构。研究结果表明, 随着hBN含量的增加, 复相陶瓷的密度将会持续下降, 气孔率先是急剧上升, 然后趋于平缓, 力学性能持续下降, 干摩擦条件下复相陶瓷与GCr15配副的摩擦学性能呈现先提高后降低的趋势, 当hBN含量低于20wt%时, 随着hBN含量的增加, 摩擦系数和磨损率逐渐减小; 当hBN含量大于20wt%时, 摩擦系数和磨损率急剧增大; hBN含量为20wt%时, 获得最低的摩擦系数为0.31。hBN的引入直接影响Si₃N₄-hBN复相陶瓷的微观组织结构, 进而影响复合陶瓷的力学性能和摩擦学性能。     

高填充Al2O3-聚丙烯酰胺复合材料的摩擦学特性

利用凝胶注模方法可以制备出高填充含量的Al2O3-聚丙烯酰胺复合材料。考察了PTFE对高填充聚合物复合材料摩擦学性能的影响，并对复合材料的磨损机理进行了探讨。研究表明．在适当高的填充条件下．复合材料的力学性能和摩擦磨损性能可以得到一定的改善，PTFE的填充将降低Al2O3-聚丙烯酰胺复合材料的力学性能，并使材料的摩擦系数有所增大；但是复合材料的耐磨特性可以得到显著改善。高填充含量的PTFE-Al2O3聚丙烯酰胺复合材料表现出了摩阻材料特性。Al2O3-聚丙烯酰胺复合材料的磨损主要表现为磨粒磨损特征。     

空心微珠-碳纤维共混改性聚酰亚胺复合材料的摩擦学性能

通过模压成型制备了碳纤维与空心微珠共混改性的聚酰亚胺复合材料, 采用MRH-3型摩擦磨损试验机研究了空心微珠含量、滑动速度及载荷对复合材料摩擦学性能的影响, 并对其磨损形貌及机制进行了分析。结果表明: 空心微珠-碳纤维/聚酰亚胺复合材料摩擦学性能优于其单独填充的聚酰亚胺基复合材料; 空心微珠含量对共混改性的复合材料摩擦系数影响不大, 但其磨损率随着空心微珠含量的增加先减小后增大; 15%空心微珠-10%碳纤维(质量分数)共混增强的复合材料的减摩耐磨性能最佳; 随着滑动速度提高, 空心微珠-碳纤维/聚酰亚胺复合材料的摩擦系数下降, 磨损率增大; 空心微珠-碳纤维/聚酰亚胺复合材料摩擦系数随着载荷增加先下降后上升, 而磨损率则随着载荷增加而增大; 空心微珠-碳纤维/聚酰亚胺的主要磨损机制在较低载荷时为磨粒磨损, 在较高载荷时为粘着磨损和磨粒磨损。     

纳米SiC和微米SiC填充聚醚醚酮的磨损机理研究

利用热压法分别以纳米ＳｉＣ和微米ＳｉＣ作为填产制取了两类不同ＳｉＣ填充的聚醚醚酮复合材料，并对它们在干摩擦条件下的摩擦磨损性能进行了研究，同时还用扫描电子显微镜对摩擦表面形貌进行了观察，进而对材料的磨损机理作了分析与讨论。研究结果表明，１０％（ｗｔ）纳米ＳｉＣ作为填料能有效的改善其填充聚醚醚酮的摩擦磨损性能，而相同含量的微米ＳｉＣ作为填为只能使其填充聚醚醚酮的耐磨性能有所改善，但没有减摩效果。微米     

改性纳米Si_3N_4/环氧树脂复合材料的摩擦磨损特性

研究纳米氮化硅粒子(Si3N4)填充环氧树脂复合材料的滑动干摩擦磨损特性,着重探讨纳米粒子表面接枝共聚改性、粒子含量对复合材料摩擦磨损性能的影响。通过对复合材料磨损表面的粗糙度及形貌分析探讨复合材料的磨损机理。结果表明,纳米氮化硅粒子能在很低的含量下(0.18%(体积分数,下同))显著提高环氧树脂的耐磨性、并降低其摩擦系数,而经过接枝共聚改性的纳米Si3N4粒子填充的复合材料的上述性能改善更为明显,耐磨性比Si3N4/EP提高3倍,摩擦系数降低20%。这说明,在Si3N4纳米粒子表面进行接枝共聚后,有利于加强粒子与基体的界面结合,从而改善复合材料的摩擦学性能。     

聚醚砜对连续碳纤维/聚醚醚酮复合材料性能的影响

以聚醚砜(PES)作为第三组分及活化PES作为连续碳纤维(CCF)的表面改性剂制备CCF/聚醚醚酮(PEEK)复合材料,重点研究CCF/PEEK复合材料的制备工艺方法对其性能的影响。结果表明:PES作为第三组分制备的CCF/PEEK复合材料,当填充16wt%的CCF时,复合材料表面电阻降低到107~109 Ω,出现导电逾渗状态,此时摩擦系数降到最低(0.2430)。活化PES作为表面改性剂制备的CCF/PEEK复合材料,当填充30wt%的CCF时,复合材料的拉伸强度、弯曲强度、冲击强度分别提高到236.2 MPa、345.1 MPa、12.3 kJ/m2,相比无PES改性的CCF30/PEEK复合材料分别提高了13.69%,21.70%,36.97%,其中PES起到显著的均匀分散CCF与界面粘结作用。摩擦学研究结果表明,复合材料的摩擦性能不仅取决于润滑材料CCF在基体中的分布还取决于CCF与基体的界面作用力。      

纳米TiO2填充聚醚砜酮复合材料的摩擦学性能

采用热压成型的方法制备了纳米TiO2填充聚醚砜酮(PPESK)复合材料，在MM—2000摩擦磨损试验机上考察了干摩擦条件下纳米TiO2含量以及试验载荷对复合材料摩擦磨损性能的影响，并利用扫描电子显微镜(SEM)观察分析PPESK及纳米TiO2／PPESK复合材料磨损表面形貌及磨损机理。结果表明，添加少量纳米TiO2即可以明显提高PPESK的耐磨性，当纳米TiO2含量超过2．5％(体积)时，其耐磨性随填料含量变化不明显，载荷对纳米TiO2填充PPESK复合材料磨损率的影响不大。在低含量时(＜2．5％)，纳米TiO2具有减摩效果，高含量时反而比未填充时大；随量载荷的增加，填充PPESK的摩擦系数显著降低。     

聚醚醚酮及其复合材料的摩擦学研究进展

评述了聚醚醚酮（PEEK）及其复合材料的摩擦磨损性能，在滑动过程中形成的摩擦转移膜以及磨屑的研究，总结了聚合物基复合材料摩擦学研究的一般方法及规律，介绍了关于用PEEK复合材料制造的轴承，齿轮等进行的摩擦学研究，以及等离子体表面处理和颗粒增强对PEEK及其复合材料摩擦学性能的影响。     

水润滑条件下氧化锆颗粒及碳纤维共混增强聚醚醚酮复合材料的摩擦性能研究

通过熔融共混法制备了碳纤维(CF)和氧化锆颗粒(ZrO_2)共混增强聚醚醚酮(PEEK)复合材料,并对其水中的摩擦学性能进行了研究。实验结果表明,该混杂增强复合材料在水中具有优异的摩擦学性能,其摩擦系数随载荷的增加无明显变化,而磨损率则随着载荷的增加而逐渐降低。该材料在水中的磨损机制主要表现为轻微的磨粒磨损和疲劳磨损,碳纤维是复合材料耐磨性得到增强的主要原因,其作为复合材料摩擦面表层的主要承载相,承担了两摩擦面之间的大部分载荷,并保护聚合物基体免于受到对磨副的严重磨损。氧化锆颗粒的加入则有效抑制了摩擦过程中碳纤维的破损与脱落,从而使得混杂增强PEEK复合材料比单纯碳纤维增强的PEEK复合材料具有更加优异的耐磨性能。但过多颗粒的加入会加剧疲劳磨损,从而降低材料的耐磨性。     

PTFE复合材料的摩擦学性能及力学性能

利用MM-200型磨损试验机,对不同填料填充PTFE复合材料的摩擦磨损性能进行了研究,并探讨了淬火处理对PTFE复合材料摩擦学性能及力学性能的影响.研究发现,几乎所有填料均可大大降低PTFE复合材料的磨损,但其对PTFE复合材料性能的影响差别较大.聚苯脂填充PTFE复合材料虽然具有良好的摩擦磨损性能,但是其拉伸强度较小.PI增大了PTFE复合材料的摩擦系数,随着PI含量的增加,PTFE复合材料的拉伸强度增大,而其伸长率则减小.CdO填充PTFE复合材料虽具有良好的摩擦性能,但其伸长率较大.淬火处理使PTFE复合材料的结晶度下降,从而导致PTFE复合材料的硬度减小、耐磨性变差.     

甲基硅油微胶囊/聚苯乙烯复合材料及其摩擦学性能

以甲基硅油为芯材,三聚氰胺-甲醛树脂为壁材,采用原位聚合法合成了具有自润滑功能的微胶囊(MCLMs);以苯乙烯(St)为单体、偶氮二异丁腈(AIBN)为引发剂、MCLMs为功能填料通过本体浇注法制备了MCLMs/聚苯乙烯(PS)复合材料。采用扫描电镜、透射电镜、纳米压痕仪表征了MCLMs的表观形貌和壳层硬度,通过高速环块摩擦磨损试验机、热重分析和万能试验机评价了复合材料的摩擦磨损性能、热稳定性能和力学性能,对复合材料的磨损形貌进行了观察。结果表明,添加质量分数为15%的MCLMs复合材料在100 N,50 r/min下的摩擦系数为0.22,磨损率降低92%;MCLMs对聚苯乙烯基体增韧效果显著。     

莫来石与碳纤维协同填充的聚四氟乙烯基复合材料及其摩擦学性能

为了提高聚四氟乙烯（PTFE）的摩擦学性能,采用机械混匀、带温预压及烧结等工艺制备了莫来石和碳纤维填充的PTFE基复合材料,并通过FTIR、XRD、万能材料试验机、洛氏硬度计、DSC及热机械分析分别表征了PTFE基复合材料的显微结构、力学性能和热学性能;然后,使用MRH-3 型高速环块磨损试验机测定了复合材料的摩擦系数和磨损率,通过自制的硅油砂浆磨损装置测定了复合材料在不同温度下的耐砂浆磨损性能;最后,借助3D测量激光显微镜研究了复合材料摩擦面形貌,并分析了摩擦磨损机制。结果表明:莫来石和碳纤维在PTFE体系中起到填充增强作用,20wt%莫来石-10wt%碳纤维/PTFE复合材料的弹性模量由364 MPa增加至874 MPa;20wt%莫来石-10wt%碳纤维/PTFE复合材料的干摩擦系数较大,但其磨损率与纯PTFE相比降低了3个数量级以上,且此复合材料在水摩擦条件下仍能保持较好的摩擦系数和磨损率,摩擦系数为0.157,磨损率为7.40×10-6 mm3·N-1·m-1;此外,20wt%莫来石-10wt%碳纤维/PTFE复合材料在较高温度下仍能表现出良好的耐砂浆磨损性能。所得结论表明改性得到的PTFE 基复合材料的摩擦学性能显著提高,复合材料可用于有杆抽油井防偏磨。      

二硫化钼填充聚酰亚胺复合材料的摩擦学性能

利用MM-200型摩擦磨损试验机,对不同体积含量MoS2填充聚酰亚胺（PI）复合材料在干摩擦条件下与GCr15轴承钢对摩时的摩擦磨损性能进行了研究,并利用扫描电子显微镜对PI复合材料及其偶件的磨损表面进行了分析。研究发现,添加MoS2可有效降低PI复合材料的摩擦系数,且PI复合材料的摩擦系数随MoS2含量的增大而减小。除PI＋10％MoS2外,其它含量MoS2填充PI复合材料的耐磨性能均明显优于纯PI材料,但当MoS2的含量超过30％后,PI复合材料的磨损率基本不随MoS2含量变化。在较高的载荷条件下,MoS2填充PI复合材料均呈现出良好的减摩耐磨性能。     

MoS_2和石墨对Ni-Cr基复合材料摩擦学性能的影响

用粉末冶金方法制备Ni-Cr基自润滑复合材料,研究了固体润滑剂MoS_2和石墨对复合材料的机械性能和摩擦学性能的影响。结果表明,随着MoS_2含量的增加,复合材料的显微硬度明显降低;MoS_2添加量从10%(质量分数,下同)增加到15%,复合材料摩擦系数和磨损率的变化并不明显。随着石墨含量的增加,复合材料的显微硬度呈逐渐降低的趋势,在400℃和800℃的摩擦系数呈升高趋势,石墨添加量为10%时室温摩擦系数最小。同时添加5%MoS_2和10%石墨时,复合材料的摩擦系数保持在0.48-0.65,石墨与MoS_2之间存在着协同效应,但是磨损率比添加单一润滑剂时高一个数量级。     

双马来酰亚胺复合材料摩擦学性能的研究

采用浇铸成型法制备了两类双马来酰亚胺复合材料,分别考察了石墨、纳米Si3N4的添加量对复合材料摩擦学性能和力学性能的影响,用扫描电镜对复合材料的磨损表面形貌进行了分析.结果表明:纳米Si3N4对改善双马来酰亚胺的摩擦磨损性能方面比石墨更有效,尤其是当纳米Si3N4的添加量为1.5%(质量分数)时,复合材料的摩擦磨损性能最佳,摩擦系数降为0.25,磨损率下降72%.     

Tribological behaviour of proposed polymeric bearing materials

The aim of the present work is to introduce new polymeric bearing materials. The proposed polymeric composites are consisting of polyethylene (PE), polypropylene (PP) and polystyrene (PS) and filled by fibres of polytetrafluoroethylene (PTFE) in concentration up to 25 wt.% as well as different types of natural oils such as (corn oil, olive oil, paraffin oil, glycerin oil, castor oil and sunflower oil) in concentration up to 10 wt.%. The frictional behavior of the proposed composites and wear resistance are investigated at different values of applied load. Based on the experimental observations, it was found that for composites free of oil, friction of PS and PE specimens decreased, while friction of PP specimens slightly increased with increasing PTFE content. PP composites filled by corn oil showed slight friction increase. Besides, friction coefficient displayed by PS and PE specimens filled by glycerin oil decreased with increasing oil content, while friction coefficient displayed by PP specimens showed consistent trend. It was noted that, PE filled with 7.5% glycerin oil and 20 wt.% PTFE displayed the minimum value of friction coefficient (0.07). This friction coefficient values recommend those composites to be used as bearing materials. PE filled by glycerin oil displayed relatively lower friction values due its common known good lubricating property. Friction of PE composites filled by paraffin oil drastically decreased with the increasing oil content. PP composites showed the lowest wear values. In addition to that, it was shown that wear displayed by composites filled by glycerin oil was higher than that containing corn oil, while wear of the tested composites filled with olive oil showed lower values than that displayed by corn oil filled composites. Composites containing 5.0–7.5% paraffin oil content showed good wear resistance which recommends them to be used as bearing material. Wear of PP, PS and PE composites filled with sunflower oil and 15 wt.% PTFE drastically decreased with increasing oil content. The minimum wear was displayed by PP and PE composites filled with 10% oil content.     

La2O3填充超高分子量聚乙烯的摩擦磨损性能

用La2O3对超高分子量聚乙烯(UHMWPE)进行了填充改性，测试了La2O3填充量对其硬度及摩擦学性能的影响。用扫描电镜观察了材料摩擦表面磨痕形貌。结果发现：随着La2O3含量的增加，UHMWPE—La2O3复合材料的硬度上升。填充量为6％的UHMWPE—La2O3复合材料在干摩擦及磨粒磨损条件下的磨损率都最小。UHMWPE在干摩擦下的磨损主要表现为犁沟及粘着，填充La2O3可减轻磨损表面的犁沟，但填充量过高，磨损转变为表面脆性脱落。     

Compression and wear behavior of composites filled with various nanoparticles

Extrusion compression and dry sliding were carried out on the various nanoparticle filled composites by using cylindrical specimens. To study the effect of exfoliated nanoparticles on the epoxy matrix to friction and wear, Na-montmorillonite and titanium dioxide nanoparticles were prepared with the filler content varied from 0 to 10 vol.%. Compression tests were conducted by using cylindrical blocks to obtain the mechanical properties of the nanocomposites. To determine the tribological property, the sliding wear tests with high pressure were performed at room temperatures by using a block-on-disc apparatus. The morphologies of the wear trace and the interlayer mechanism of the as-spun material were obtained by using X-ray diffractometer (XRD) and scanning electron microscopy (SEM). Experimental results showed that the compression strength, fracture strength and Young’s modulus for both reinforced nanocomposites are much higher than that of pure epoxy matrix. The friction coefficient and wear coefficient of Cloisite^® 30B nanocomposites were effectively reduced with rising filler content which should be attributed to the improved dispersion of the nanoparticles. Finally, the SEM observation on the wear tracks surface for the pure epoxy matrix and its composites filled with various kinds of nanoparticle will be discussed.     

Study on the effects of nanoparticulates of SiC,Al2O3, and ZnO on the mechanical and tribological performance of epoxy-based nanocomposites

In this research work, mechanical and tribological characteristics of ortho cresol novalac epoxy (OCNE)-based nanocomposites filled with nanoparticulates of SiC, Al₂O_3, and ZnO have been investigated. Also, in these investigations, the influence of wear parameters such as applied normal load, sliding velocity, filler contents, and sliding distance have been explored. The experimental plan for four factors at three levels using face centered composite design (CCD) has been employed by the response surface methodology (RSM) technique. The friction and wear tests were carried out using a pin on disc wear test apparatus under dry sliding conditions. The hardness and flexural strength of nano ortho cresol novalac epoxy composites filled with nano (SiC, Al₂O_3, and ZnO) particulates increases with an increase in the filler contents. Whereas, the tensile strength of these nanocomposites increases with an increase in the filler contents from 1 to 2 wt%, and with a further increase in filler contents the tensile strength decreases. The results of the study also showed that (2 wt%) filler contents bring superior mechanical and tribological properties. The lowest coefficient of friction and specific wear rate were found with nano Al₂O₃-filled composites. Also, the wear mechanisms of these nanocomposites were studied using a scanning electron microscope (SEM) equipped with an EDS analyzer.     

多孔PEEK自润滑材料的制备与摩擦磨损性能

采用模压-滤取和高温真空熔渍工艺制备了多孔聚醚醚酮(PEEK)发汗式自润滑材料,并分别考察了成型压力、造孔剂含量和润滑油脂种类对PEEK多孔自润滑材料的摩擦磨损性能的影响。结果表明,压力为100MPa,NaCl的质量分数为30%,采用通用锂基脂时,所得多孔PEEK自润滑材料的磨损率最低,200N下磨损率为2.73×10-16m3/(N.m),与纯PEEK干摩擦相比耐磨性提高了1245倍,其耐磨性较经典的炭纤维增强PEEK复合材料还提高了32倍。研究表明,多孔结构能够储存润滑油,在摩擦过程中能通过发汗作用在对偶面上形成稳定连续的油膜而起到良好的润滑作用,从而大幅降低复合材料的摩擦系数和磨损率。