改性酚醛树脂陶瓷摩擦材料的摩擦磨损性能

以普通酚醛树脂、硼改性酚醛树脂、三聚氰胺改性酚醛树脂为黏结剂,以陶瓷纤维为增强纤维,制备了3种酚醛树脂陶瓷摩擦材料。对其冲击韧性和硬度进行实验测试,采用摩擦磨损试验机考察其摩擦磨损性能,采用扫描电子显微镜(SEM)和X射线能谱仪分析其磨损表面形貌及其成分,并探讨其磨损机制。结果表明:硼改性酚醛树脂黏结剂能够提高摩擦材料的硬度,三聚氰胺改性酚醛树脂黏结剂能够提高摩擦材料的冲击韧性,降低摩擦材料硬度;在摩擦过程中三聚氰胺改性酚醛树脂在高温下炭化,在摩擦材料表面形成一层致密的摩擦层,摩擦层的存在使摩擦材料的摩擦因数相对比较稳定,降低了摩擦材料的磨损率。     

桐油改性线型酚醛树脂的制造及应用研究

介绍桐油改性线型酚醛树脂的制造方法及应用研究。苯酚，甲醛，桐油在酸催化下进行加成缩合聚合反应制得的桐油改性线型酚醛树脂，是国内我未见报导的桐油改性酚醛树脂新品种。用该树肥作为粘接制造的汽车摩擦材料的主要性能指标，均超过国家规定的标准。其中，刹车片衬片的缺口冲击强度平均达到了４．１１ｄＪ／ｃｍ＾２，离合器面片的弯曲强度平均达到了５４．４ＭＰａ，最大应变平均达到了９．２×１０＾－３ｍｍ／ｍｍ。对制品的     

摩擦材料用改性酚醛树脂的研究进展

酚醛树脂是摩擦材料中最重要的基体材料，但是纯酚醛树脂存在脆性大、耐热性不足等缺陷，因此要对酚醛树脂进行改性以提高其耐热性和韧性。主要介绍了近年来常用的几种化学改性酚醛树脂和物理改性酚醛树脂及其对摩擦材料性能的影响。     

纳米铜改性酚醛树脂及其应用性能

采用新发明的原位生成法成功地制备了摩擦材料用纳米铜改性酚醛树脂。利用XRD和TEM对所制备的树脂进行了表征。结果显示,纳米铜的粒径为10~40 nm,呈近球形。进行了TGA、冲击试验和摩擦试验。结果表明,纳米铜改性酚醛树脂的耐热性有较大提高,与纯酚醛树脂相比,其初始分解温度和半分解温度可分别提高31℃和46℃;纳米铜改性酚醛树脂基摩擦材料的韧性和摩擦学性能有明显改善,与纯酚醛树脂基摩擦材料相比,冲击强度提高44%,热衰退率和磨损率分别降低约50%和2/3。建立了酚醛树脂/纳米铜复合材料的界面模型,并探讨了纳米铜改善酚醛树脂及摩擦材料性能的机理。      

摩擦材料用酚醛树脂改性研究进展

综述了近年来摩擦材料用酚醛树脂增韧、增强以及耐热改性的研究进展。分析比较了橡胶、植物油、无机纳米材料、纤维以及聚苯并噁嗪树脂等改性体系对酚醛树脂基摩擦材料性能的影响。纳米粉末橡胶可同时提高酚醛树脂的耐热性和韧性,弥补了传统橡胶改性的不足;植物油可提高酚醛树脂的韧性,但也会使其的耐热性下降;无机纳米粒子的团聚问题影响其改性效果;纤维对酚醛树脂有增强增韧作用外,还可以明显改善其摩擦性能;而天然纤维可再生、价廉,而且强度高,但作为摩擦材料增强体,其耐热性有待改善;新型热固性酚醛树脂固化温度较高,要取代传统酚醛树脂还须进一步深入研究。     

NAO刹车片树脂基体的研究进展

树脂基体作为粘结剂，对NAO刹车片的各项性能有着很大的影响，酚醛树脂已经不能满足要求，必须对酚醛树脂进行物理或化学改性。通过分析酚醛树脂的分子结构特点，指出了酚醛树脂的改性途径和方向。全面介绍了近年来常用的几种化学和物理改性酚醛树脂方法，以及对刹车片摩擦材料性能的影响。     

桐油改性酚醛树脂的耐热性研究

本文对桐油改性酚醛树脂的一些性能进行了研究，并着重利用ＤＴＡ、ＴＧ热分析技术研究了这类改性树脂的耐热性能及其热分解动力学。实验结果表明，桐油改性酚醛树脂的热分解分为两个阶段：第一个分解峰为４５０～４９０℃，约分解３０～４５％；第二个分解峰为５７０～６７０℃，约分解３５～５５％。随着甲醛／苯酚摩尔比的增加，初始分解温度逐渐升高。这种经桐油改性的酚醛树脂耐热性能可达：初始分解温度３５９．４～３８３．７     

蒙脱土插层改性酚醛树脂复合材料及其摩擦磨损性能

利用单体原位插层的方法制备酚醛树脂/蒙脱土复合材料,研究了蒙脱土的有机化改性和不同有机化蒙脱土含量对酚醛树脂耐热性的影响,以及改性后的酚醛树脂对摩擦材料性能的影响,结果表明:经改性的酚醛树脂的耐热性能要明显优于未改性的酚醛树脂,初始分解温度达487.1℃,比未改性的提高了60.9℃,600℃时的质量剩余率达54.84%,提高了38%。100~350℃摩擦系数为0.33~0.40,250℃时未改性树脂基摩擦材料磨损率为0.56×10-7/N·m,改性后树脂基摩擦材料磨损率为0.44×10-7/N·m,下降了27.2%。     

树脂粘结剂对汽车摩擦材料性能的影响

制备了不同树脂基体和不同树脂含量的汽车摩擦材料,研究了树脂种类与含量对汽车摩擦材料的机械性能和摩擦磨损性能的影响。结果表明,腰果壳油改性酚醛树脂为基体的摩擦材料的摩擦、耐热和力学性能,均优于纯酚醛树脂基摩擦材料。树脂-丁腈橡胶共混改性摩擦材料具有更好的力学性能和耐磨性,摩擦系数稳定。随着树脂粘结剂含量的增加,摩擦材料的力学性能提高。树脂粘结剂的含量在9%~12%时,摩擦材料具有优异的摩擦磨损性能;树脂粘结剂的含量小于6%时,摩擦系数较低且不稳定;树脂粘结剂的含量大于15%时,材料发生热衰退现象。      

铜纤维／芳纶浆粕混杂增强摩擦材料的冲击性能研究

以冲击强度为主要考察目标,研究了酚醛树脂种类及含量、混杂纤维配比及含量对铜纤维/芳纶浆粕混杂增强摩擦材料冲击性能的影响,借助SEM观察了摩擦材料的冲击断面.结果表明,丁腈橡胶改性酚醛树脂为基体的摩擦材料的冲击强度优于腰果壳油/三聚氰胺改性酚醛树脂基摩擦材料,但硬度有所提高;铜纤维中加入芳纶浆粕的混杂纤维形式可显著提高摩擦材料的冲击强度;在树脂含量35%、纤维含量18%(质量分数)、纤维混杂比1∶1时体系的冲击强度最高为3.63kJ·m-2.     

Friction and wear behavior of carbon fiber reinforced brake materials

A new composite brake material was fabricated with metallic powders, barium sulphate and modified phenolic resin as the matrix and carbon fiber as the reinforced material. The friction, wear and fade characteristics of this composite were determined using a D-MS friction material testing machine. The surface structure of carbon fiber reinforced friction materials was analyzed by scanning electronic microscopy (SEM). Glass fiberreinforced and asbestos fiber-reinforced composites with the same matrix were also fabricated for comparison. The carbon fiber-reinforced friction materials (CFRFM) shows lower wear rate than those of glass fiber- and asbestos fiber-reinforced composites in the temperature range of 100°C-300°C. It is interesting that the frictional coefficient of the carbon fiber-reinforced friction materials increases as frictional temperature increases from 100°C to 300°C, while the frictional coefficients of the other two composites decrease during the increasing temperatures. Based on the SEM observation, the wear mechanism of CFRFM at low temperatures included fiber thinning and pull-out. At high temperature, the phenolic matrix was degraded and more pull-out enhanced fiber was demonstrated. The properties of carbon fiber may be the main reason that the CFRFM possess excellent tribological performances.     

有机复合摩擦材料的成分优化及其对摩擦性能的影响

采用正交试验设计方法对有机复合摩擦材料的成分进行优化,利用MMS-2A摩擦磨损试验机对材料的摩擦系数进行测试,用比磨损率表征复合材料的磨损性能,并通过极差法对试验结果进行了分析。用Leica体式显微镜和3D激光共聚焦显微镜观察了材料摩擦磨损后的表面形貌,探索了不同成分下合成材料的摩擦磨损机理。结果表明:改性酚醛树脂对材料的平均摩擦系数和比磨损率的影响最大。摩擦系数较优的组合为A1B1C2D2,比磨损率较优的组合为A3D1C1B3。树脂含量较少时,摩擦表面的摩擦膜较少,犁沟较深,呈严重的磨粒磨损特征;随树脂含量增加,摩擦表面形成完整且连续的摩擦膜,犁沟较浅,材料的主要磨损形式为粘着磨损和磨粒磨损。     

1-2-3 型摩擦制动复合材料的研究

针对近年来摩擦制动材料的发展要求, 选用2 维的片状蛭石与1 维的Kevlar 纤维混杂作为增强体, 在配方及工艺研究的基础上, 成功地研制出1-2-3 型复合增强摩擦材料。其性能及机理研究表明: 此摩擦材料力学性能高, 摩擦性能稳定, 特别是高温磨损小, 是一种具有广阔发展前景的摩擦制动材料。      

Evaluation of flyash-filled and aramid fibre reinforced hybrid polymer matrix composites (PMC) for friction braking applications

Flyash-filled and aramid fibre reinforced phenolic based hybrid polymer matrix composites (PMC) were fabricated followed by their characterization and tribo-evaluation. The friction-fade and friction-recovery behaviour has been rigorously evaluated as a function of in situ braking induced temperature rise in the disc at the braking interface on a Krauss friction testing machine as per the ECE regulations. The fade behaviour has been observed to be highly dependent on the weight fraction of resin i.e. followed a consistent decrease with the decrease in the flyash content, whereas the frictional fluctuations (μ_max − μ_min) has been observed to decrease with the increase in flyash content. A higher recovery response is registered when the flyash content is 80 wt.%. The analysis of friction performance has revealed that the fade and static friction response are the major determinants of overall frictional response. Wear analysis has revealed that material integrity and temperature rise of the disc decide the wear behaviour. Worn surface morphology investigation using SEM has revealed that the dynamics of formation–destruction of contact-patches (friction-layers) and topographical attributes largely influence the friction and wear performance of such composite brake-pads.     

纤维增强摩阻材料中树脂含量的确定

选用碳纤维、钢纤维和FB酚醛树脂为主要成分制得纤维增强摩阻材料 ,研究了树脂含量对材料摩阻性能、力学性能的影响 ,确定了摩阻材料的最低树脂含量为 1 6% ,最佳树脂含量为 2 2 %     

木材陶瓷的研究现状与应用前景

木材陶瓷是一种以木材或其他木质材料为原料,经树脂浸渍、高温碳化而形成的一种新型多孔炭素材料.因其较高的强度以及电、磁和摩擦等方面的独特处,使它成为兼具结构和功能的双重材料,同时由于木材的可再生性和良好的环境协调性又使它成为一种环境材料.本文介绍木材陶瓷的发展、性能与制备工艺,综述了木材陶瓷的研究现状及存在的问题,对其应用和发展前景进行了展望.     

基于人造海绵的碳/环氧树脂网络互穿复合材料的制备及磨损性能研究

采用人造海绵为模板,通过浸渍酚醛树脂和环氧树脂,制备了具有海绵构造的碳/环氧树脂网络互穿复合材料。并研究了该复合材料的微观形貌及摩擦磨损性能。结果发现人造海绵的网络状构造很好地复制到了复合材料中。与环氧树脂相比,复合材料的磨损率和摩擦系数都降低了。复合材料中的网状碳限制了环氧树脂基体的应变和回弹能力,使其摩擦系数变动范围变小。显示出此类复合材料具有更加稳定的摩擦磨损性能。     

FKF纤维增强新型制动摩擦材料的研制

基于国内汽车摩擦材料行业的现状和生产成本的考虑,选用FKF纤维为主体增强纤维,改性酚醛树脂为基体,研制出FKF纤维增强新型制动摩擦材料.性能研究结果表明,新型摩擦材料的摩擦系数适宜且稳定,耐磨性能好,是一种理想的汽车摩擦材料.     

Effects of Mixing the Steel and Carbon Fibers on the Friction and Wear Properties of a PMC Friction Material

Friction, fade and wear characteristics of a PMC friction material containing phenolic resin, short carbon fiber, graphite, quartz, barite and steel fiber were investigated through using a small-scale friction testing machine. Four different friction materials with different relative amounts of the carbon fiber and steel fiber were manufactured and tested. Comparing with our previous work which contained only steel fiber as reinforcement, friction characteristics such as fade and recovery and wear resistance were improved significantly by adding a small amount of carbon fiber. For the mixing of carbon and steel fiber, the best frictional and wear behavior was observed with sample containing 4 weight percentage carbon fiber. Worn surface of this specimen was observed by optical microscopy. Results showed that carbon fibers played a significant role in the formation of friction film, which was closely related to the friction performance. The brake pad with Steel fibers in our previous work, showed low friction coefficient and high wear rate. In addition, a friction film was formed on the surface with a relatively poor quality. In contrast, the samples with mixing the steel and carbon fiber generated a stable friction film on the pad surface, which provided excellent friction stability with less wear.