Submitted by Chaylane Marques (chaylane.marques@ufpe.br) on 2015-03-10T19:04:33Z No. of bitstreams: 2 Tese_Luiz_Gustavo_R_Souza.pdf: 7771003 bytes, checksum: 8d90a791d6be10e6fea340893dbfdaab (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-10T19:04:33Z (GMT). No. of bitstreams: 2 Tese_Luiz_Gustavo_R_Souza.pdf: 7771003 bytes, checksum: 8d90a791d6be10e6fea340893dbfdaab (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2012 / CAPES; FACEPE; CNPQ / A subfamília Gilliesioideae (Alliaceae) está dividida em duas tribos, Ipheieae e Gilliesieae, que apresentam fortes diferenças morfológicas, biogeográficas e filogenéticas. O presente trabalho objetivou realizar uma análise citotaxonômica e filogenética nessa subfamília, por meio da comparação de número e morfologia cromossômica, dupla coloração com os fluorocromos cromomicina A3 (CMA) e 4’,6-diamidino-2-fenilindol (DAPI), localização do DNA telomérico e dos sítios de DNAr 5S e 45S por hibridização in situ fluorescente (FISH) juntamente com uma análise filogenética de alguns gêneros a partir de sequências de DNA nuclear ITS e DNA plastidiais trnG, trnL-trnF, entre outras. A tribo Ipheieae é formada pelos gêneros Ipheion, Leucocoryne, Nothoscordum, Tristagma e Zoellnerallium. Desses, Nothoscordum é cariotipicamente mais diversificado, com dois números cromossômicos básicos, x = 4 e x = 5, recorrentes eventos de translocações Robertsonianas e poliploidia. Nesse gênero foram analisados dois complexos taxonômicos, Inodorum e Bivalve, onde as análises de hibridização genômica in situ (GISH) e filogenia molecular permitiram caracterizar a origem híbrida de N. gracile e N. bonariense, respectivamente, bem como de suas relações com as espécies afins. A análise das espécies de Leucocoryne, também com x = 5, trouxe novas evidências sobre a relação evolutiva entre as espécies que possuem três estames funcionais e aquelas que conservam os seis estames férteis, comum nas demais Alliaceae. As análises filogenéticas permitiram validar o gênero Zoellnerallium, que apresenta um cariótipo único na tribo com 2n = 24 (8M + 16A) e cromossomos menores do que as demais espécies da tribo. No caso das três espécies de Ipheion as análises citogenéticas mostraram cromossomos menores que os demais da tribo, cariótipos predominantemente formados por acrocêntricos e um número cromossômico único para cada espécie do gênero (2n = 12, 14 e 20). A tribo Gilliesieae é formada pelos gêneros Gethyum, Gilliesia, Miersia, Speea e Solaria, todos com o mesmo número fundamental NF = 11 mas com diferentes números cromossômicos. A evolução cariotípica da tribo foi moldada principalmente por disploidia ascendente, partindo do cariótipo ancestral 2n = 12, presente em Miersia e Speea, e em linhagens independentes dando origem a 2n = 14, presente em Gethyum, Gilliesia e Solaria, e 2n = 20 presente em Miersia. De uma maneira geral, todas as espécies da subfamília Gilliesioideae apresentaram um par de sítios de DNAr 5S por conjunto monoploide, exceto a secção Nothoscordum do gênero Nothoscordum que apresentou uma amplificação desses sítios. Os sítios de DNAr 45S foram localizados preferencialmente nos braços curtos dos cromossomos acrocêntricos, sugerindo uma correlação entre as fissões cêntricas e este tipo de DNAr. Embora os dados sugiram que as fusões/fissões cêntricas tenham sido a principal mudança cromossômica envolvida na evolução da subfamília Gilliesioideae, as análises do DNA telomérico em Nothoscordum e Ipheion não revelaram nenhuma relação aparente entre fusões cêntricas e sítios ectópicos de DNA telomérico.

Este trabalho dedica-se ao entendimento da construção do conteúdo disponibilizado pelos meios de comunicação e sua recepção pela audiência. Procurou-se compreender o processo da apropriação de um fenômeno social, a formação de grupos sociais informais e não-institucionais pelo cinema, e de que modo o discurso criado é recebido pelo próprio grupo social representado no filme. Para tanto, foram tomados como objetos de pesquisa e análise o grupo dos praticantes da arte marcial jiu-jitsu, o filme Red Belt e o experimento empírico de projeção do filme a um grupo focal composto por um subgrupo dos indivíduos pesquisados. Como fundamentação teórica, foram cruzadas proposições de autores da sociologia, como Michel Maffesoli e sua confirguração e caracterização das Tribos Urbanas; da comunicação, expressas nas ideias de Theodor Adorno e Marshall McLuhan; e dos estudos culturais e de recepção, representados pelos textos de Stuart Hall. A metodologia aplicada foi essencialmente qualitativa, com uso de técnicas de pesquisa etnográfica, sobretudo nas pequisas de campo realizadas no acompanhamento dos treinamentos da equipe de jiu-jitsu do Professor Sazinho e durante a realização do grupo focal. Em busca dos objectivos estipulados, os componentes do objeto desta pesquisa foram contextualizados, segmentados e analisados: o fenômeno da formação dos grupos sociais urbanos; o contexto histórico-social e as características do grupo de praticantes de jiu-jitsu em Fortaleza; o filme Red Belt e a construção do discurso proposto por este. Essas etapas serviram de preparação à fase final da pesquisa, a realização do grupo focal, onde representantes – os praticantes de jiu-jitsu – foram confrontados com sua representação – o filme Red Belt. [...]

Submitted by Dominick Jesus (dominickdejesus@hotmail.com) on 2016-02-02T19:44:58Z No. of bitstreams: 2 Dissertação_Héctor Jaime Gasca Alvarez.pdf: 13762745 bytes, checksum: e958548660b8b2eef43f22abf72486f6 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-02-02T19:44:58Z (GMT). No. of bitstreams: 2 Dissertação_Héctor Jaime Gasca Alvarez.pdf: 13762745 bytes, checksum: e958548660b8b2eef43f22abf72486f6 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2008-04-22 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The Oryctini (Coleoptera: Scarabaeidae: Dynastinae) it a large tribe of worldwide distribution with approximately 26 genera and 230 species. Fourteen genera and 113 species are distributed in the Neotropical region. This group of scarab beetles is characterized by a generally large and robust body, black or brown coloration, exposed mandibles, protíbia tri- or quadridentate with large teeth, and pronounced sexual dimorphism with the males possessing prominent tubercles or horns on the head and/or pronotum. Adults are nocturnally active and generally feed on rotting fruits or decaying vegetation. Knowledge of the tribe in the Neotropics is fragmentary, necessitating further studies that address taxonomy, biology and geographical distribution patterns. This study is a faunistic survey of the Oryctini of the Brazilian Amazon. The composition of the group in the study area is 7 genera and 19 species found in 7 states, 91 municipal districts, and approximately 167 specific localities. States with larger number of species are Amazonas and Pará, with 17 and 13 respectively. Heterogomphus eteocles Burmeister, 1847, Heterogomphus aidoneus (Perty, 1830), Heterogomphus telamon Burmeister, 1847, Megaceras crassum Prell, 1914, and Megaceras laevipenne Prell, 1914, are reported for the first time from the study area. Megaceras laevipenne is reported for the first time from Brazil. The taxomony, descriptions, distribution maps, and biological and ecological data are provided for all species. A characters analysis is provided as well as an identification key for all Oryctini species that occur in Brazilian Amazon. / A tribo Oryctini (Coleoptera: Scarabaeidae: Dynastinae) é um grupo de distribuição mundial formada por 26 gêneros e aproximadamente 230 espécies, dos quais 14 gêneros e 113 espécies estão distribuídas na região Neotropical. Este grupo de coleópteros pode ser reconhecido pela presença de um corpo geralmente grande e robusto, coloração escura, preta ou castanha, mandíbulas largas e expostas, protíbias com três a quatro dentículos grandes e um acentuado dimorfismo sexual, onde os machos possuem tubérculos ou cornos proeminentes no pronoto e/ou a cabeça. Os adultos têm hábitos noturnos e se alimentam usualmente de matéria vegetal em decomposição ou de frutos doces apodrecidos O conhecimento da tribo no Neotrópico ainda é escasso sendo necessários estudos que ajudem a esclarecer aspectos relacionados com a taxonomia, biologia e padrões de distribuição geográfica das espécies. Realizou-se um estudo faunístico para a tribo Oryctini da Amazônia brasileira. A diversidade no grupo para a região estudada está representada por 7 gêneros e 19 espécies, registradas em 7 estados, 91 municípios e aproximadamente 167 localidades. Os Estados com maior número de espécies foram o Amazonas e o Pará, com 17 e 13 respectivamente. São registradas pela primeira vez para a Amazônia brasileira as espécies Heterogomphus eteocles Burmeister, 1847, Heterogomphus aidoneus (Perty, 1830), Heterogomphus telamon Burmeister, 1847, Megaceras crassum Prell, 1914 e Megaceras laevipenne Prell, 1914, sendo esta última novo registro para o Brasil. A taxonomia, descrições morfológicas, dados biológicos e ecológicos, e mapas de distribução geográfica são apresentados para cada espécie. A partir de um análise de caracteres taxonômicos, foi elaborada uma chave dicotômica para a identificação das espécies de Oryctini que ocorrem na Amazônia brasileira.

Electrochemical Mechanical Polishing (ECMP) has become increasingly important due to the continuous decrease of the device size in integrated circuit (IC) fabrication. Tantalum (Ta) is a promising material as a substitute for copper in ICs. This dissertation studies the tribology and electrochemistry of Ta ECMP. The present research uses experimental combined analysis approaches. A specially designed experimental setup assembling a tribometer and a potentiostat was used to carry out Ta ECMP. The friction force and electrochemical reactions were measured simultaneously. Using this setup, we found the factors which affected the frictional behaviors of Ta during ECMP. The technique of single frequency electrochemical impedance spectroscopy (EIS) was employed to investigate the material removal mechanisms in Ta ECMP. The results presented the competing mechanisms of removal and formation of a surface oxide layer of Ta. In order to further the investigation in a nanoscale, the atomic force microscope (AFM) was used to measure the material removal rate. The Preston equation for the Ta ECMP was established. A new methodology was developed to study the oxidation state and process of Ta during ECMP. Through comparing the material removal rate measured by using the AFM and the calculated one via the Faraday’s law, the distribution of the Ta suboxides and pentoxide, as well as the oxidation process, was revealed. The oxidation process was strongly dependent of the applied anodic potential, thickness of the oxide layer, mechanical forces, and surface orientation. A polymer environmental cell was designed and produced. Using this cell and AFM, it was found that the material removal in the nanometer scale was a function of the surface orientations. This research is beneficial for optimization of the Ta ECMP process. This dissertation includes six chapters. After Introduction and Motivation and Objectives, the material, setup, and testing conditions are discussed in Chapter III. Chapter IV discusses the tribology and material removal mechanisms in Ta ECMP, while Chapter V the oxidation of Ta during ECMP, followed by Conclusions and Future Work.

Traditionally, there are several kinds of method for restraining wear. Usually, it includes the choice of the best operating conditions, the surface coating, the surface heat treatment, and the choice of the best lubricants. Among these methods, only the choice of the best lubricants has the mendable process of chemical element for worn surface, others do not have the mendable process. Consequently, this project proposes a method of continuous tribo-plating, and takes preliminary experiments by using SUJ2 ball specimen and S45C disk specimen to investigate the effects of rotational speed, anode¡¦s density of current, and specimen¡¦s surface roughness on the coating growing rate and the coefficient of friction. Results show that the coating growing rate increases with increasing rotational speed and anode¡¦s density of current, but it doesn¡¦t be influenced by surface roughness. According to the experimental results, it is found that the frictional coefficient in order is uncoated specimen, coated specimen, and continuous coated specimen. Furthermore, at continuous tribo-plating test, specimen whose surface roughness is rough has lower frictional coefficient. According to the analyses of surface pattern and composition, specimen whose surface roughness is rough remains a lot of piece-like coating film on the surface, and this residual film provides a good effect of lubrication. The result of this project proves that continuous tribo-plating not only reduces frictional loss but also has the mendable process of worn surface.

With the development of MEMS and nano-technology, effects of tribo-electrification on the size accuracy and quality of micro-element will be more sensitive. The electrification in the order of mV is also important in the nano-machining process. Therefore, the tribo-electrification mechanisms and characteristics between the metal surfaces are investigated in this study. The experiments are conducted on a reciprocating friction tester with a measuring system, and the tribo-electrification behavior is studied for eleven pure metals, namely, Platinum (Pt), Ferrous (Fe), Molybdenum (Mo), Titanium (Ti), Tungsten (W) and Lead (Pb), Zinc (Zn), Aluminum (Al), Silver (Ag), Aurum (Au), Copper (Cu), in dry severe wear process. According to the SEM and EDS observations on the wear particles and the worn surfaces, the tribo-electrification mechanisms between the metal surfaces are proposed. Concerning the study of self-mated pure metal pairs; a model of the tribo-electrification mechanism by asperity removal for five hard metal pairs of Pt/Pt, Fe/Fe, Mo/Mo, Ti/Ti, and W/W is proposed. In this model, the wear for the hard self-mated metals is mainly caused by the asperity removal with small wear particle. When the material transfers from pin specimen to plate specimen, the polarity of tribo-electrification for pin specimen becomes positive, and vice versa. Another model of the tribo-electrification mechanism by junction growth for six soft metal pairs of Pb/Pb, Zn/Zn, Al/Al, Ag/Ag, Au/Au and Cu/Cu is proposed. In this model, the wear mechanism of the soft self-mated metals is the flake-like wear particles that are formed by the particle aggregation with junction growth. The polarity of tribo-electrification for the upper specimen keeps negative due to the wear loss of the upper specimen always less than the plate specimen. Furthermore, the transition mechanisms of tribo-electrification are investigated with changing normal load, hence a map has been established to predict the polarity of tribo-electrification for self-mated metal pairs. That is, with increasing normal load, the polarity of tribo-electrification varies from the random, through tending to negative, to negative, and the formation mechanism of wear particle from the micro-asperity removal, through the transition, to the particle aggregation with junction growth. Moreover, an equation is proposed to predict the average magnitude of tribo-electrification. Results show that the average magnitude of electrification voltage is linearly proportional to the electric resistivity and the relative wear rate, but inversely to the real contact area. Concerning the study of dissimilar metal pairs of Pb/Fe, Ag/Fe, Cu/Fe, Zn/Fe and Al/Fe; the total voltage of tribo-electrification Vt for dissimilar metal pairs consists of three components: (a) tribo-electrification by material transfer Vw, Vw is independent of the reciprocating speed, and is proportional to the (1+n) power of normal load, where n is in the range from ¡V0.5 to ¡V0.9 for lead, silver, copper, zinc, and aluminum. (b) tribo-electrification by friction heat Vf, Vf is linearly proportional to the reciprocating speed, and is proportional to the square root of normal load. (c) tribo-electrification by residual heat Vr, Vr is linearly proportional to the reciprocating speed, and is proportional to the square root of normal load. Moreover, Temperature rise Tt between the contact surfaces can be calculated by Vf and Vr. Hence, Tt consists of two components: (a) temperature rise by friction heat Tf, an equation is proposed to predict Tf. Results show that Tf is a function of friction coefficient, normal load and speed. (b) temperature rise by residual heat Tr, Tr is linearly proportional to the reciprocating speed, and is proportional to the square root of normal load. Finally, a model of tribo-electrification mechanism for dissimilar metal pairs is proposed to describe the tribo-electrification phenomenon for sliding pairs with low to high mutual solubility.

Dipoles are expected to often dramatically enhance the mutual collision rate of diffusing particles (above the effects of Brownian or turbulent motion). However, this spreading awareness of the possible influence of discrete dipoles on particles is still based largely on theory, and some qualitative experience of particle behaviour from microgravity experiments. Individual particle dipoles have not yet been definitely isolated in experiments, nor measured in practical situations. In this project, it was intended to measure, for the first time, distributions of dipole strength (as well as net charge and particle size) on particulates dispersed into air by typical industrial and pharmaceutical processing methods. The instruments designed to do this were built around a sampling head which allowed examination of a flow of dust dispersed into an air stream. During dispersal, the particles suffered tribocharging by mutual separation and collision on walls. Examination of the particles involved recording the path of particles as they moved through a non-uniform electric field around a central electrode, which was supplied with high voltage. Particles were attracted towards the central electrode (of 0.5 mm diameter in this study) if they contained dipoles, independent of the polarity of the field or their net charge. Particles to be examined were illuminated by a laser sheet as they moved past, and a high speed video captured their trajectories (over a field of view of around 5 mm). The equation of motion of a particle which involved the forces of both particle net charge and dipole strength was applied to the particle path to evaluate both these parameters. The particle trajectories were modelled, and checked against the observed experimental trajectories. The voltage applied to the probe varied from 4 kV to 18 kV but for most of the runs 6 kV voltage was used. The electric field around the probe tip was assumed to be same as that for a spherical electrode of the same size as the probe. The flow field axially towards and around the probe tip was calculated using the Stokes creeping flow equations around a sphere. The calculated electric and flow fields were checked against COMSOL Multiphysics models applied to actual geometries and flow regimes. The rotation dynamics of the particles was also considered important in the technique, requiring possibly extra knowledge of the initial direction of the dipole. The flow was led through a lateral field between two plates in order to orient the direction of any dipoles in the direction of the lateral field. The expected orientation of dipoles coming out of the plates was used as an initial guess of their orientation for modelling the rotation of the dipoles when they entered the probe field. Misalignment after leaving the plate field and before entering the probe field was also considered, and was found to be important due to vortices characterised by smoke and particle studies. However, the trajectory modelling revealed that the particles studied quickly rotated into alignment with the probe field, providing maximum attractive force to the probe, and so the values of net charge and dipole strength obtained did not depend on the initial orientation. Estimated errors of particle position and diameter used in all the calculation steps were judged to be well within a basic image error limit of ±1 pixel. Some particle trajectories showed unexplainable shapes which was traced to the influence of large mixing eddies around the gas/particle jet. A check for corona discharge at the probe tip was made both at the beginning and at the end of the sampling experiments. No corona was detected initially (up to 18 kV), but a discharge could be observed at voltages close to 7 kV in the later checks. Particles of acrylic, glass bubbles, whole milk and fertiliser powder were sampled and net charges and dipole charges were estimated. The sampled particles overall had net charge and dipole charge in the range of 10-15 C to 10-12 C on individual particles with diameters 20 μm -130 μm. Dipoles were more evident (more easily measured) for glass bubbles but the presence of dipoles on other particle samples was found and could not be completely ruled out for many of them. The analysis procedure is presently time consuming but can be automated so it is recommended in the future that it should be automated. The work can be extended into industrial situations by sampling moving dust suspensions, e.g. fluid bed overflows and pneumatically conveyed outflows, useful in the dairy and fertilizer industries.

Le frottement est un phénomène inhérent à tout système mécanique entre deux corps en contact ou animés de mouvement relatif. Ce phénomène génère des pertes d'énergie et, lorsqu'il devient important, il s'accompagne de l'endommagement (usure) de la surface des pièces frottantes. Le moyen actuellement connu pour lutter contre le frottement et réduire l’usure est la lubrification qui consiste à introduire entre les surfaces frottantes un matériau qui facilite le glissement des dites surfaces et empêche le contact entre aspérités des surfaces.La technique est expérimentée avec trois composés (graphite, h-BN et MoS2) afin de montrer ses performances et son applicabilité à différents produits. Les nanoparticules sont mises en dispersion dans du dodécane. Les films déposés par la technique tribo-assistée ont une cinétique de formation instantanée. Ils ont une structure compacte pour ceux qui sont déposés à partir des nanoparticules de graphite et de MoS2 et une structure poreuse pour ceux qui sont formés à partir des nanoparticules de h-BN. Leur surface est lisse avec une épaisseur moyenne de 0,4 µm. Les tests de frottement effectués dans des conditions sévères (frottement sec) ont mis en évidence leurs performances tribologiques: ils sont immédiatement tribo-actifs, c'est à dire qu’ils présentent un faible coefficient de frottement dès le début du glissement (pas de période d’induction), il ont un fort potentiel auto-réparateur et une durabilité moyenne de 1500 cycles. La présence du liquide dans le processus de dépôt permet d'une part de ramener les nanoparticules dans le convergent du contact et d'autre part de réduire la désorganisation structurale des nanoparticules déposées et de faciliter l'orientation des particules du film avec leurs feuillets de base parallèlement à la direction de glissement. Ce travail montre ainsi les performances de la technique tribo-assistée dans l'élaboration de films minces à partir de nanoparticules de matériaux lubrifiants différents. Il permet également de comprendre les mécanismes de formation et de fonctionnement des films minces élaborés par cette technique. / Friction is a phenomenon present in any mechanical system between two parts in contact or animated with relative motion. This phenomenon generates energy losses and, when it becomes important, it can cause damage (wear) of the surface of the rubbing parts. The present known means for controlling friction and reducing wear is lubrication which consists in introducing between the friction surfaces a material which facilitates the sliding of these surfaces and prevents the contact between asperities.The technique is experimented with three compounds (graphite, h-BN and MoS2) in order to show its performance and its applicability to different products. The nanoparticles are dispersed in dodecane.The films deposited by the tribo-assisted technique have an instantaneous formation kinetics. They have a compact structure for those that are deposited from graphite and MoS2 nanoparticles and a porous structure for those that are formed from h-BN nanoparticles. Their surface is smooth with an average thickness of 0.4 μm. The friction tests carried out under severe conditions (dry friction) have demonstrated their tribological performance: they are immediately tribo-active, ie they have a low friction at the beginning of the sliding (no induction period), they have a high self-repair potential and an average durability of 1500 cycles. The presence of the liquid in the deposition process makes it possible, on the one hand, to bring the nanoparticles into the convergent contact and on the other hand to reduce the structural disorganization of the deposited nanoparticles and to facilitate the orientation of the particles of the film with their sheets of base parallel to the sliding direction. This work thus shows the performance of the tribo-assisted technique in the production of thin films from nanoparticles of different lubricating materials. It also makes it possible to understand the mechanisms of formation and operation of the thin films produced by this technique

<p style="text-align: justify;">U doktorskoj disertaciji je razmatran uticaj čvrstih čestica<br />mirkonskih razmera na kritične radne performanse kontaktnog para<br />klip-cilindar kao tipa kontakta koji je najzastupljeniji u hidrauličkim<br />komponentama. Prema konceptualnom modelu je izvedena<br />eksperimentalna instalacija na kojoj, za različite koncentracije<br />čvrstih čestica i određeni broj radnih ciklusa je ispitivan<br />intenzitet habanja, pad pritiska i veličina zapreminskih gubitaka<br />proticanja kroz zazor. Nad skupom prikupljenih eksperimentalnih<br />podataka je izvršena analiza i modelovanje funkcija koje opisuju<br />ponašanje posmatranih veličina.</p> / <p>This doctoral dissertation analyzes the influence of microscale solid particles<br />on the the critical operational performances of the most common type of<br />tribo-couples in power hydraulic components. According to the conceptual<br />model, experimental installation was made. For different solid particles<br />concentration levels and predefined number of working cycles, experimental<br />installation was used to examine intensity of wear, pressure drop and<br />volumetric efficiency &ndash; fluid loss trough the clearance. On the basis of<br />experimental data set was carried out analysis and modeling of functions that<br />describe the behavior of the observed parameters.</p>

Ce mémoire de thèse présente une analyse multi-physique des endommagements par usure provoqués sur un alliage base cobalt soumis à des sollicitations de fretting pour des températures allant de 25˚C à 600˚C. On montre alors que l’usure est sévère à basse température puis douce à haute température. À basse température, l’usure est contrôlée par une synergie entre l’oxydation de l’interface et l’abrasion de la couche d’oxyde nouvellement formée. Une formulation analytique est développée, prenant en compte ces deux aspects. Cependant, cette loi n’est valable que lorsque le produit de l’endommagement, à savoir les débris d’usure oxydés, sont immédiatement évacués de l’interface. Or, si la température dépasse une température seuil T1, les débris commencent à stagner dans l’interface, ils s’agglomèrent et modifient complètement la réponse tribologique. À haute température, une tribocouche protectrice est formée par compaction et frittage des débris, limitant drastiquement l’usure. La loi d’usure par oxydo-abrasion, décrivant le comportement tribologique à basse température, est alors modifiée pour prendre en compte l’apparition de cette tribocouche. La tribocouche, également appelée glaze layer, possède une structure multi-couches, où les propriétés d’oxydation et de diffusion des éléments d’alliage jouent un rôle prépondérant dans les modalités de sa formation. À la lumière de ces résultats, sont finalement discutés les mécanismes mis en jeu dans l’absence totale d’usure lorsque la glaze layer est efficace à l’interface. / This manuscript presents a multi-physical analysis of the fretting wear damages observed on a cobalt-based alloy. It has been showed that the wear process is severe at low temperature whereas a mild wear process takes place at high temperature. At low temperature, the wear process is driven by a synergetic action of the oxidation of the surface and the abrasion of the newly formed oxide layer. An analytical formulation is then proposed by taking into account these two phenomena. However, the proposed wear law is only valid when the wear debris is immediately ejected out of the interface. Yet, when the temperature is high enough, the debris starts to agglomerate into the interface changing completely the tribological response. At high temperature, a protective tribolayer is formed by a compaction and sintering processes of the wear debris which drastically limits wear. The oxido-abrasive wear law, describing the wear behaviour at low temperature, is then modified in order to take into account the tribolayer formation. The tribolayer, also called "glaze layer", has a multi-layerered structure whose formation is strongly linked to the oxidation and diffusive properties of the alloying elements. In the light of these results, the tribological mecanisms providing complete protection of the interface from further wear are discussed.