A presente tese descreve as etapas de desenvolvimento de um equipamento (tribômetro) e metodologia de ensaio para caracterização do efeito isolado da temperatura sobre o atrito medido em materiais de fricção utilizados em freios veiculares. O projeto deste equipamento foi baseado nas funcionalidades e limitações encontradas nas principais máquinas e procedimentos de ensaio para freios automotivos. São apresentados e discutidos detalhes do projeto mecânico e de automação do tribômetro, bem como são levantadas suas incertezas de medição instrumentais e precisão. Além disso, é proposta uma nova metodologia de ensaio para caracterização do efeito isolado da temperatura sobre os resultados de atrito obtidos durante os testes. O projeto mecânico atual do tribômetro contempla recursos que contribuem para facilitar a operacionalidade do equipamento e, consequentemente, reduzir o tempo envolvido na etapa de preparação dos testes. São exemplos destes recursos um mecanismo de fuso e manivela, o qual é empregado para a regulagem do raio de deslizamento, e um dispositivo para troca rápida da amostra a partir do ajuste de um único parafuso. O atual projeto de automação do tribômetro é composto por circuitos de controle da carga, rotação, torque e temperatura, os quais operam em malha fechada. A incerteza instrumental do sistema de medição de atrito do tribômetro é igual a ±2,9% do valor nominal medido, considerando a faixa típica de aplicação da máquina. Em termos de precisão, verificou-se experimentalmente que o equipamento projetado apresenta uma repetitividade de ±0,013. O projeto de automação também contemplou a ligação do tribômetro a um aquecedor indutivo. O uso da referida tecnologia em conjunto com a metodologia de ensaio proposta na presente tese mostraram-se capazes de caracterizar de forma acelerada e independente o efeito da temperatura sobre o coeficiente de atrito obtido a partir de ensaios de frenagem executados no tribômetro. Complementa o estudo ainda o desenvolvimento de uma técnica para pós-processamento dos dados relativos aos ensaios executados no tribômetro segundo a metodologia proposta. A referida técnica mostrou-se uma maneira eficiente e relativamente simples de avaliar os efeitos simultâneos da carga e da temperatura sobre o atrito. / The current thesis describes the development of equipment (tribometer) and testing procedure for characterizing the isolated effect of temperature on friction measurements obtained from vehicular friction materials. The design of this equipment was based on the features and limitations found in the main machinery and testing procedures for brakes. Details about the mechanical design and automation of the tribometer are presented as well as its instrumental measurement uncertainties and precision. Besides, a new testing procedure is proposed in order to characterize the isolated effect of temperature on friction results obtained in the tests. The current mechanical design of the tribometer comprises some features that contribute to make the equipment operation ease and thus reduce its setup time. A crank and screw mechanism, which is used for adjusting the sliding radius, and a device for rapid exchange of the samples by means of a single screw are both examples of those features. The current automation design of the tribometer consists of circuits for controlling load, speed, torque and temperature, which operate in closed loop mode. The instrumental measurement uncertainty from the friction measuring system is ±2,9% of the nominal friction measurement, considering the typical operating range of the machine. Experimental tests performed on the tribometer showed that the repeatability (precision) of the friction measurements is ±0,013. The automation design also included the connection between the tribometer and an induction heater. The use of this technology together with the proposed testing procedure proved to be a suitable tool for characterizing the isolated effect of temperature on friction during braking tests performed on the tribometer. This work is also complemented by the development of a technique for post-processing the data related to the tests carried out in accordance with the proposed testing procedure for the tribometer. This technique proved to be an efficient and clear way to assess the simultaneous effects of load and temperature on friction measurements.

Orientador: Edison Bittencourt / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-16T04:51:00Z (GMT). No. of bitstreams: 1 Silveira_JoaoViniciosWirbitzkida_M.pdf: 8775567 bytes, checksum: 35a926d080f0ec01d62b71fe89882b3d (MD5) Previous issue date: 2010 / Resumo: As pastilhas de freio são materiais compósitos que têm sido constantemente aperfeiçoadas, principalmente pela substituição por materiais que melhorem o desempenho destes elementos ou diminuam os impactos ao homem e ao meio ambiente. Com a procura de materiais de fontes renováveis para substituir materiais sintéticos, a lignina, uma macromolécula natural encontrada em vegetais e abundantemente na madeira, se torna uma alternativa altamente viável para emprego em diversos tipos de materiais, entre eles os materiais compósitos. O objetivo desta pesquisa é desenvolver resinas com substituição parcial da resina fenólica por teores diversos de lignosulfonato de amônio e estudar o comportamento de pastilhas de freios fabricadas com tais resinas e reforçadas com fibras de aramida. São empregados ensaios analíticos de caracterização (FT-IR, DSC, TGA, DMA, ângulo de contato, MEV e EDS) e métodos já utilizados na indústria automobilística (ensaio Krauss e desgaste) para caracterizar e verificar o desempenho desses materiais. O lignosulfonato, apesar de possuir menos grupos fenólicos disponíveis para a reação de reticulação que o próprio fenol livre, é capaz de reagir formando uma matriz polimérica, porém as propriedades tribológicas ficam um pouco comprometidas. O coeficiente de atrito médio encontrado é de aproximadamente µm=0,4, um pouco acima dos valores de pastilhas comerciais, entretanto apresentam boa estabilidade quanto ao desempenho dos freios e ao desgaste. A estrutura do compósito vista com auxílio de microscópio eletrônico se apresenta pouco homogênea. Os resultados satisfatórios e compatíveis com os atuais materiais de fricção possibilitam a incorporação desta resina no processo de fabricação de materiais de fricção. / Abstract: Brake pads are composite materials, which have been constantly improved, mainly by the replacement of materials that improve the performance of the braking process, or that reduce the impacts of it on human beings and environment. Through the search for renewable materials to replace the synthetic ones, lignin becomes a highly viable alternative to be employed in several kinds of materials, including the composite ones. Lignin can be found in vegetables and it is plentiful in wood. This research aims to develop a resin with partial replacement of phenolic resin by different contents of ammonium lignosulfonate and to study the behavior of brake pads produced with these resins and reinforced with aramid fibers. Analytical characterization (FT-IR, DSC, TGA, DMA, contact angle, SEM and EDS) and methods commonly used in automotive industry (Krauss method and wear) are used to characterize and verify the performance of these materials. Despite lignosulfonate has less phenolic groups available for reticulation reaction than free phenol itself, it is able to react forming a polymeric matrix, but tribological properties are compromised a bit. Average friction coefficient found is about µm=0,4, a value slightly higher than the one of commercial brake pads. However, they show good stability related to braking performance and wear. Composite structure observed with the aid of scanning electron microscopy shows itself a heterogeneous material. Satisfactory results, compatible with current friction materials, allow the incorporation of this resin in the process of manufacturing friction materials. / Mestrado / Ciencia e Tecnologia de Materiais / Mestre em Engenharia Química

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Introdução: Biofilme consiste em um conjunto de microrganismos embutidos em uma matriz extracelular. O biofilme tradicional (TBF) se desenvolve em locais com contínua hidratação, e o biofilme buildup (BBF), em produtos para a saúde expostos a repetidos ciclos de sujidade, limpeza, desinfecção e secagem. Objetivo: avaliar o impacto do uso de detergente e fricção para remover biofilme buildup-5 (BBF-5) e biofilme tradicional-5 (TBF-5) de canais endoscópicos gastrointestinais flexíveis, bem como o impacto do glutaraldeído após a limpeza. Métodos: O BBF-5 foi desenvolvido após a exposição da superfície interna dos canais de endoscópicos gastrointestinais ao Artificial Test Soil (ATS) contendo 108UFC/ml de Pseudomonas aeruginosa (PA) e Enterococcus faecalis (EF), limpeza, desinfecção de alto nível (DAN), enxágue e secagem durante cinco dias. O mesmo processo foi utilizado para desenvolver o TBF-5, porém a fase de DAN foi omitida. Limpeza com detergentes com enzimas de pH neutro e detergentes sem enzimas com pH alcalino, escova com cerdas e dispositivo de limpeza pull thru foram comparados à limpeza com água e sem fricção para remover o BBF-5 e o TBF-5. Testes de proteína e carboidrato, contagem de bactérias viáveis e adenosina trifosfato (ATP) foram realizados. Teste de Kruskal-Wallis e análise de post hoc Dunn-Bonferroni foram realizados. Resultados: Não houve diferença estatisticamente significante (p>0,05) entre a quantidade de EF e PA nos canais com TBF-5 e BBF-5. Não houve diferença da eficácia para a remoção de PA em TBF-5 entre o detergente enzimático e a água, em ambas as situações, a limpeza apenas não foi eficaz (p>0,05) na ausência de fricção (flush). Por outro lado, o detergente alcalino, associado a todos os procedimentos de limpeza (ausência e presença de fricção) e DAN, foi eficaz para remoção de PA. Para a remoção de EF em TBF-5, a eficácia da limpeza foi alcançada em todas situações avaliadas (com e sem fricção) com o uso do detergente enzimático; com a água, na presença de fricção (pull thru e escovas de cerdas); e com detergente alcalino, apenas com o método de limpeza com escovas de cerdas (p<0,05). Para a remoção de bactérias em BBF-5, formados em canais de PTFE, não houve diferença da eficácia para a remoção de PA entre o detergente enzimático e o alcalino, em ambas situações, todos os procedimentos avaliados foram eficazes (p<0,05), enquanto que a água foi ineficaz para remoção de PA apenas na ausência de fricção (p>0,05). Para a remoção de EF em BBF-5, o detergente enzimático e a água foram eficazes em todas situações avaliadas; o detergente alcalino, foi eficaz na presença de fricção com o dispositivo pull thru e escovas de cerdas (p<0,05). Testes de ATP, proteína e carboidrato foram incapazes de detectar biofilme. Conclusão: Água potável de torneira, detergente com enzimas e detergente alcalino sem enzimas foram eficazes para a completa remoção de BBF-5 e TBF-5 na presença de fricção (pull thru ou escova com cerdas) durante a limpeza. Na ausência de fricção, detergente enzimático apresentou maior habilidade para remover E. faecalis de TBF-5 e BBF-5, detergente alcalino para remover P. aeruginosa e a água não foi eficaz para a remoção de ambos microrganismos. Glutaraldeído destruiu bactérias remanescente após a maioria das combinações de limpeza avaliadas. / Background: Biofilm is the accumulation of microorganisms enclosed in an extracellular matrix. Traditional biofilm (TBF) develops under continuous hydration whereas buildup biofilm (BBF) develops on medical devices that are exposed to repeated cycles of soiling, cleaning, disinfection and drying. Objetive: to evaluat the impact of detergent and friction on BBF-5 and and TBF-5 removal from PTFE channels as well as the killing efficacy of glutaraldehyde post cleaning. Methods: BBF-5 was developed by repeated rounds over five days of exposure to bacteria, cleaning, high level disinfection (HLD), rinsing and drying of the inner surface of new polytetrafluorethylene (PTFE) channels. Artificial Test Soil (ATS) containing 108CFU/ml of Pseudomonas aeruginosa (PA), and Enterococcus faecalis (EF) was used for the bacterial exposure. The same process was used to develop TBF-5, however the HLD step was omitted. Cleaning with enzymatic and alkaline detergents, bristle brush and pull thru cleaner were compared to a water-flush only to determine BBF-5 and TBF-5 removal. The residual organic and microbial levels were tested using carbohydrate, and protein assays as well viable count, and adenosine triphosphate (ATP) testing. Kruskal-Wallis test and the post hoc Dunn-Bonferroni analysis were performed. Results: There was not a statistically significant difference (p> 0.05) between the amount of EF and PA in the channels with TBF-5 and BBF-5. There was not a difference in efficacy for the removal of PA in TBF- 5 between the enzymatic detergent and water and in both situations, only cleaning was not effective (p>0.05) in the absence of friction (flush). Furthermore, the alkaline detergent, associated with all cleaning procedures (absence and presence of friction) and DAN, was effective for the removal of PA. For removal of EF in TBF-5, cleaning efficacy was achieved in all procedures evaluated (with and without friction) with the use of enzymatic detergent; with water in the presence of friction (pull thru and bristle brushes); and an alkaline detergent, the only method of cleaning brushes with bristles (p<0.05). For the removal of bacteria in BBF-5 formed on PTFE channels, there was not a difference in efficacy for PA removal of the enzymatic and alkalyne detergent and in both situations, all procedures were evaluated effective (p<0.05 ), while water was ineffective for PA removal only in the absence of friction (p>0.05). For EF removal on BEF-5, the enzymatic detergent and water were evaluated effective in all situations; alkaline detergent, was effective in the presence of friction with the pull thru device and bristle brushes (p<0.05). ATP, protein and carbohydrate testing were unable to detect biofilm. Conclusion: Tap water, enzymatic and alkaline detergent were effective for complete BBF-5 and TBF-5 removal in the presence of friction (pull thru or bristle brush) and a flushing pump during the cleaning. Without friction, enzymatic detergent was more effective for EF removal of TBF-5 and BBF-5, alkalyne detergent was more effective for PA removal and water was not effective for both types of bacterial removal. Glutaraldehyde effectively killed the remaining microorganisms after some cleaning combinations were tested.

Neste trabalho, a relação entre a adesão e o grau de desordem de superfícies em contato é estudada por meio de simulações por dinâmica molecular. O sistema em estudo é composto por um indentador cilíndrico rígido e um bloco deformável. Um reservatório térmico é colocado logo abaixo do bloco, de forma a manter o sistema a temperatura ambiente. Os sólidos são feitos do mesmo material e são modelados por intermédio do potencial genérico de Lennard-Jones. A adesão entre as superfícies é variada gradualmente por meio da variação do raio de corte do potencial que descreve a interação entre as superfícies indentador-bloco. Cada simulação se inicia com um recozimento, após o qual são realizadas as simulações de contato propriamente ditas, até que ocorra penetração de 1,7 raios atômicos. A força normal, a energia potencial, a temperatura e a energia cinética são acompanhadas ao longo do processo. Os resultados reforçam a importância da adesão no jump-to-contact, estando este fenômeno relacionado à geração de defeitos cristalinos. Há indícios de que a distribuição da carga, bem como a dissipação de energia, seja influenciada pela adesão na interface. Mostra-se que a desordem apresentada pelos átomos do bloco é proporcional à contribuição da adesão. / In this work, the relationship between adhesion and the degree of disorder of surfaces in contact is studied by means of molecular dynamics simulations. The system consists of a rigid cylindrical indenter and a deformable block. A heat reservoir is placed just below the block, in order to maintain the system at room temperature. Both solids are made of the same material and are modeled through the generic Lennard-Jones potential. Adhesion between the surfaces is gradually varied by varying the cut-off radius of the potential describing the interaction between the indenter surface and the block. Each contact simulation is preceeded by an annealing step, and is conducted until the penetration reaches 1.7 atomic radii. The normal force, the potential energy, kinetic energy and temperature are monitored throughout the process. The results reinforce the importance of adhesion in the phenomenon of jump-to-contact, which is also related to the generation of crystalline defects. The results indicate that the load distribution and power dissipation is influenced by the adhesion at the interface. It is shown that the disorder presented by the atoms of the block is proportional to the contribution of adhesion.

Orientador: Robson Pederiva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-19T13:48:38Z (GMT). No. of bitstreams: 1 Suetti_AndreGarciaLima_M.pdf: 20585864 bytes, checksum: 84c85d26b6df77562a52c8ca3aa2aedf (MD5) Previous issue date: 2011 / Resumo: O interesse da indústria automobilística em projetar freios menos ruidosos vem incentivando pesquisas na área de acústica e vibração. A compreensão de um dos principais fenômenos de excitação de vibração em sistemas com atrito, o stick-slip, é de grande importância para o aprofundamento desses estudos, que muitas vezes não consideram uma fonte de excitação bem definida e realimentada, recorrendo a excitações impulsivas ou com frequências aleatórias. O stick-slip é uma vibração auto-excitada que pode ocorrer em um corpo fixo que se atrita com outro corpo que está em movimento, fundamentada na diferença entre o coeficiente de atrito estático e dinâmico. Tendo em vista a aplicação da excitação por stick-slip em vibrações em sistemas de freio, equacionamentos analíticos são propostos nesse trabalho tendo a dificuldade incrementada gradualmente. Um estudo dos efeitos do amortecimento em sistemas com stick-slip é também proposto, apresentando um comportamento que difere de sistemas mecânicos sem realimentação. Com o objetivo de se avaliar esses métodos, realizam-se simulações numéricas e um experimento, que se utiliza de materiais de atrito e disco empregados em freios. Os resultados demonstram a compatibilidade das simulações numéricas e os dados obtidos experimentalmente, o que comprova que os métodos podem ser usados na simulação do problema / Abstract: Interest of the automotive industry in designing quieter brakes has encouraged the researches in the fields of acoustics and vibration. Understanding one of the main phenomena of vibration excitation in systems with friction, stick-slip, is crucial to a deeper study. Many a time these studies do not consider a well-defined and fed back source, falling back on impulsive and random excitations. The stick -slip is a self-excited vibration that may occur when a static body rubs against a dynamic one. It is based on the difference between the static and dynamic friction coefficients. Considering the stick-slip excitation in the braking system vibration, analytical equations with continuous incremental difficulties are proposed herein. A study of the effects of damping in stick -slip systems is also proposed, presenting a kind of behavior that is different from that of mechanical systems without feedback. In order to evaluate these methods, an experimental or sometimes numerical simulation is conducted using friction material and discs used in braking systems. The results are in agreement with the experimental data, proving that the methods can be used in simulations of problems / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Submitted in fulfillment of the requirements for the degree of Master in Engineering: Mechanical Engineering, Durban University of Technology, Durban, South Africa, 2017. / Despite the huge improvements made in the development of vehicle brake pad materials, problems such long stopping distances, noise pollution, and heat dissipation still continue to persist. In this regard, a novel polymer-based hybrid nanocomposite brake pad (HC) has been developed. Here, a combination of carbon-based materials, including those at a nanoscale, was used to produce the brake pad. The coefficient of friction, wear rate, noise level, and interfacial temperature was investigated and compared with that of a commercial brake pad material (CR). It was found that the brake pad performance varied with the formulation of each pad. Hybrid nanocomposite brake pads material exhibited superior performance in most tests when compared to the commercial brake pad. They exhibited a 65% lower wear rate, 55% lower noise level, 90% shorter stopping distance, and 71 % lower interfacial temperature than the commercial brake pad (CR). Furthermore, mechanical properties such as hardness, compressive strength, shear strength, and impact resistance were also evaluated. The material exhibited a 376% higher shear strength, 100% improved compressive strength, 77% greater modulus and 100% higher impact strength than the commercial brake pad. The hardness of both brake pads material was statistically comparable. Additionally, the thermal stability, degradation, water and oil absorption behaviour were measured. It was found that HC brake pad material exhibited a 100% lower water absorption and 80% oil absorption rate. The brake pads also exhibited a thermal stability within the brake pad standard maximum working temperature of 300 -400 0C. The superior performance of hybrid nanocomposite brake pad material observed was due to synergism between the carbon-carbon additives and uniform dispersion of carbon fiber as shown in Figure 4.16. Scanning electron microscopy study was subsequently performed on fracture and worn surfaces of the brake pads. The micrographs show changes in the structural formation after the incorporation of carbon based fillers. It also shows the smooth structure and uniform dispersion of the carbon fiber. The smooth surface of the worn brake pad is an indicative of a harder structure. No ploughing or score marks were evident. Hence, it was deduced that the reinforced had superior mechanical and tribological properties. These improved properties are suggestive of materials that may be successfully used for brake pad application. / M

Les films minces de Diamond-Like Carbon sont couramment employés dans les moteurs automobiles. Leur très faible coefficient de frottement et leur haute dureté permettent en effet d’optimiser les performances et la durée de vie des véhicules. Cependant, la plupart des lubrifiants utilisés dans les moteurs sont élaborés pour fonctionner avec des surfaces métalliques. Il est donc envisageable d’améliorer le comportement tribologique de films de DLC en leur conférant un caractère métallique par l’introduction d’éléments dopants en quantité limitée et contrôlée (15 % au maximum) dans la matrice de carbone amorphe. Un réacteur de dépôt industriel muni d’une technologie de dépôt hybride a été utilisé. Celle-ci combine la PECVD pour l’élaboration du DLC hydrogéné à la pulvérisation cathodique magnétron pour le dopage. Quatre éléments ont été introduits à différentes concentrations dans le DLC : aluminium, cuivre, molybdène et niobium. Les propriétés physico-chimiques des dépôts ont été caractérisées par XPS (composition et liaisons chimiques) et spectroscopie Raman (structure). La dureté, le frottement et l’usure à sec et en conditions lubrifiées, ainsi que l’énergie de surface des films ont également été caractérisés. Deux études in situ de tenue des DLC en température ont été conduites par spectroscopie Raman. Par comparaison avec un film de DLC pur, le dopage entraîne une modification de la structure du DLC, et par conséquent une réduction de la dureté des couches. Cependant, excepté dans le cas du cuivre, ceci s’accompagne d’une diminution significative du coefficient de frottement et de l’usure à sec des couches. En revanche, en dépit de ce résultat prometteur, l’impact sur les propriétés tribologiques en milieu lubrifié est plus modéré et fortement lié à la composition du lubrifiant employé. Enfin le transfert industriel du dopage a été étudié et validé dans le cas du dopage à l’aluminium. / Diamond-Like Carbon thin films are commonly used in automotive engines. Thanks to their very low friction coefficient and high hardness, it is indeed possible to optimize the performances and the lifetime of vehicles. However, most of the lubricants that are used in engines are designed to be in contact with metallic surfaces. So it might be possible to improve the global tribological behaviour of DLC films by giving them a metallic character. This can be achieved with the introduction of doping elements in limited and controlled amount (maximum 15 at. %) in the amorphous carbon matrix. An industrial scale reactor has been used with a hybrid coating technology combining PECVD for the deposition of hydrogenated DLC and magnetron sputtering for the introduction of the dopants. Four elements have been tested with various amounts in the DLC: aluminium, copper, molybdenum and niobium. The physico-chemical properties of the films have been characterized by XPS (chemical composition and bonding) and Raman spectroscopy (structure). Hardness, friction and wear in both dry and lubricated conditions, and surface energy have also been determined. Two in situ studies under temperature have been conducted by Raman spectroscopy for deposited thin films. Compared to a pure DLC, doping led to a modification of the structure resulting in a decrease in hardness. However, except for copper doping, a significant reduction of friction and wear in dry conditions is observed. Despite this promising result, the impact of doping on lubricated tribological behaviour is limited and strongly dependent on the composition of the lubricant itself. Finally, the industrial transfer of DLC metallic doping has been studied and validated.

Polymers as construction material are common in the industry. Although more recently the use of polymer composites in more demanding applications has increased, requiring more of them mechanically, tribologically and thermally. To enhance the properties various fillers are used, from common glass fibers to more advanced nanoparticles. For this study three types of base polymers have been studied: poly-amide (PA), poly-phenylene-sulphide (PPS) and poly-ether-ether-ketone (PEEK). They have been filled with glass fibers, carbon fibers, poly-tetra-fluoro-ethylene (PTFE), graphite and thermally conductive modifier in various combinations. Fibers are used to increase the mechanical properties, PTFE and graphite are added as lubricating additives to reduce the friction, and the thermally conductive modifier to increase the thermal conductivity. Five general groups of polymer composites were studied. Pure PEEK PPS, PA and PEEK filled with fibers PPS, PA and PEEK filled with fibers and lubricating additives PA filled with lubricating additives PEEK filled with fibers and additives for lubrication and thermal conductivity The polymer composites have been tribologically tested in a reciprocating sliding test set-up. Friction, wear and surface damage have been studied. Three types of counter surfaces have been used: ball bearing steel balls, stainless steel cylinders and anodized aluminum cylinders. Load, surface temperature of the polymer composites and number of cycles were varied to study any changes in friction and wear. The wear marks on the polymer composites were studied using an SEM. Cross sections of some tested samples were prepared to study any subsurface damage. From the tests the polymer composites showed similarities in friction. Lubricating additives gave lower friction, often around 0.05-0.15, while pure and only reinforced gave higher, often around 0.4-0.5. The wear was also less for polymer composites with lubricating additives. There was no clear influence of temperature but for most tests an increase in temperature gave lower friction. The only influence of load was that higher load gave wider wear tracks. Since no cross sections were prepared to compare subsurface damage due to different loads there might be a possibility that there were some differences below the surface as well. Otherwise cross sections showed that polymer composites with only fibers had cracks and cracked fibers below the surface due to the high stresses the polymer composite had been subjected to. With lubricating additives there was no large subsurface damage and it seems as if the lubricating additives formed a protective tribofilm in the wear track, giving both lower friction and wear. The presence of such a tribofilm was confirmed by XPS analysis that showed a surface layer containing F from PTFE. The conclusions are that the tribological properties of a polymer composite are strongly dependent on its fillers. Lubricating additives form a tribofilm that lowers friction and wear. Elevated temperatures might drastically change the tribological behavior of a polymer composite why it is important to do tests at higher temperatures. Cross sections can give information about subsurface damage and might help to understand the wear mechanisms and deformation of polymer composites better. More microscopy and mechanism studies are required in order to further understand the tribological behavior of polymer composites.