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1
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GABRIEL MASCHIO
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Reheat Treatment on Supermartensitic Stainless Steel: Study of Microstructural and Mechanical Effects
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Leader : CINTHIA GABRIELY ZIMMER
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MEMBRES DE LA BANQUE :
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AFONSO REGULY
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ANDRE ZIMMER
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CINTHIA GABRIELY ZIMMER
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CLEBER RODRIGO DE LIMA LESSA
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ELISABETE PINTO DA SILVA
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Data: 19 janv. 2022
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Afficher le Résumé
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Mechanical components for critical applications demand solid properties, which are directly related to the material chemical composition and microstructure. Equipment used in oil and gas wells require special attention, because errors on their building might lead to failures or even catastrophes. In these cases, high corrosion resistance alloys such as stainless steels, are widely used. Furthermore, heat treatments are essential to achieve application purposes. When a material does not meet the specified properties, in many cases the heat retreatment is performed in order to adjust the features that have not been met. Although this process is commonly used, there are only a few sources of literature about the effects of metals heat retreatment. Thus, this investigation analyses the supermartensitic stainless steel quenched and tempered, which is one of the most used metallic alloys for building oil and gas well completion equipment. Therefore, samples of this material were heat treated and retreated from one to six times in order to map the morphological characteristics of microstructure and mechanical properties resulting from this process. Once done, metallographic analyses, tensile tests and Charpy impact tests were performed on each retreated sample. The analyses over microstructure showed a grain refinement after each heat retreatment and a non-linear variation of retained austenite portion and of mechanical properties. The conclusion is that each heat retreatment promotes two main changes in the resulting microstructure, the grain refinement and the variation in the content of retained austenite. As the latter is not linear, the results of mechanical properties are different for each heat retreatment. The variations observed in the grain size and in the contents of retained austenite can result in different behaviors of other important properties of the material, such as its resistance to some corrosion methods, its susceptibility to hydrogen embrittlement and its fluency resistance.
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2
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DIOGO HOFMAM
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DEVELOPMENT OF A LOW COST CHEMICAL COMPOSITION APPLIED TO AUSTEMPERED DUCTILE CAST IRON THROUGH THE THE AID OF NEURAL NETWORKS
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Leader : CLEBER RODRIGO DE LIMA LESSA
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MEMBRES DE LA BANQUE :
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CINTHIA GABRIELY ZIMMER
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DANIELA LUPINACCI VILLANOVA
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VINICIUS KARLINSKI DE BARCELLOS
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Data: 14 mars 2022
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This work presents the development of a low-cost chemical composition for the production of an austempered nodular cast iron (ADI) that meets the ASTM A897/897M - 2016 Grade 2 1050/750/07 standard with the aid of artificial neural networks. Through extensive analysis of chemical compositions and mechanical properties found in the literature, information was compiled to insert into neural networks, seeking an optimization in the relationship between chemical composition, mechanical properties and cost for the production of the material. Based on the chemical composition obtained, the casting and subsequent heat treatment of the material was performed. With the produced material, it was machined and mechanical and metallographic tests such as tensile test, hardness, optical test, scanning microscopy and x-ray diffraction were performed. As a result, it was understood that artificial neural networks can be used to assist in the production of an ADI that reaches standardized values and at a considerably lower cost compared to its competitors, with savings of up to 49%. Thus, a smaller number of natural resources can be used achieving the desired mechanical and microstructural properties.
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3
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ALEXANDRE ROMAN
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FRICTION MATERIAL WEAR: EFFECTS AND INTERACTIONS BETWEEN SERVICE BRAKE TEMPERATURE, LINING CONTACT PRESSURE, AND VEHICLE SPEED
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Leader : ALEXANDRE LUIS GASPARIN
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MEMBRES DE LA BANQUE :
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ALEXANDRE LUIS GASPARIN
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EDSON LUIZ FRANCISQUETTI
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GUILHERME VIEIRA BRAGA LEMOS
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JULIANO CANTARELLI TONIOLO
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Data: 17 mars 2022
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International standards and original equipment manufacturers (OEM) procedures usually define wear tests in organic friction materials focusing on the brake lining temperature. The current work presents an approach combining different brake pads temperatures, vehicle speeds, and brake pressures for analyzing their effects and interactions in the friction material wear through dynamometer tests. Therefore, mechanical properties were evaluated, where internal shear strength had the most significant influence on wear; furthermore, compressive strength and flexural strength did not considerably change with variations on the test parameters. A 23 factorial design of the experiment (DOE) showed that the brake temperature alone was not the main factor for increasing wear, and the primary wear mechanism was abrasion. Furthermore, higher vehicle speed (80 km/h) along with greater brake pressure (3 bar) promoted the highest friction material mass loss (10.8 g).
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4
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CHAIANE NEUMANN
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INTERACTION BETWEEN TYPE I AND II COAGENTS AND POLYBUTADIENE ISOMERS ON CROSSLINKING SYSTEMS USING ORGANIC PEROXIDE
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Leader : DAIANE ROMANZINI
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MEMBRES DE LA BANQUE :
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ALEXANDRE LUIS GASPARIN
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ANA MARIA COULON GRISA
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DAIANE ROMANZINI
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MARA ZENI ANDRADE
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Data: 30 juin 2022
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This study aims to evaluate the impact of different polybutadiene isomers in crosslinking systems via organic peroxides using type I and type II coagents. For the study, dicumyl peroxide (DCP) was used in association with EGDMA (ethyleneglicol dymethacrylate) and TAIC (triallylcyanurate) coagents in the crosslinking of high cis-1,4-butadiene and high 1,2 polybutadiene (vinyl) isomers. The results presented to the moment are consistent with the literature, whose studies show that elastomers with high 1,2-butadiene content are more reactive in organic peroxide systems. Coagents are maintaining their presumed behavior in crosslinking with peroxides, where the type I coagent (EGDMA) modifies the crosslinking kinetics, whereas the type II coagent (TAIC) maintains the original curing characteristics. Up to this moment, preliminary conclusions are consistent with literature, and lead to the understanding that polybutadiene with high vinyl content is highly more reactive than its isomer cis. However, it stands out the increasing of crosslinking index when added coagent type I to the vinyl isomer.
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5
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LUCAS PEREIRA DE JESUS
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QUANTIFICAÇÃO DE AUSTENITA RETIDA EM AÇOS ATRAVÉS DE UM MÉTODO MAGNÉTICO NÃO DESTRUTIVO
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Leader : CINTHIA GABRIELY ZIMMER
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MEMBRES DE LA BANQUE :
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ALEXANDRE LUIS GASPARIN
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CAMILA DOS SANTOS TORRES
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RAFAEL GUSTAVO SCHREIBER
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Data: 22 août 2022
Ata de defesa assinada:
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Afficher le Résumé
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This research project aims to develop new equipment for quantification of retained austenite in heat-treated martensitic steels, in a fast and non-destructive way: a balance that relates the magnetic response of a specimen, with the quantity of phase present. The higher the percentage of retained austenite there is in the steel, the less will be its magnetic response. The device was developed using low-cost material, and simplified construction allocated over an electromagnetic plate. To authenticate the equipment was manufactured and head treated square section specimens with 20 x 20 mm using SAE 5160 steel, with different thicknesses and heat treatment temperatures, i.e., raw, quenched, quenched and tempered, and quenched and double tempered, with the purpose to get different retained austenite fractions. Also, were selected parts manufactured by a factory, to test the equipment with parts with different sections. The specimens and parts were quantified on the conventional method to obtain retained austenite fraction (x-ray diffraction, quantitative metallography, and feritoscope) and then in the device developed in this project. To analyze the results was utilized the analysis of variance method (ANOVA), using the design of the experiment in randomized blocks. The electromagnetic balance is quantified in a fast and effective way with the square section specimens, regardless of their thickness, according to ANOVA analysis, the percentage of retained austenite acquired does not differs statistically from the results obtained with the conventional methods. In the end, the aim of this study, to develop equipment that applies a non-destructive quantification, was not reached, because the equipment only worked in specimens with square sections. So, for the next research, there is a need to improve the device so that it works in other geometry situations.
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6
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JONAS LUDWIG DE BITENCOURT
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Method for determining the efficiency of vermicomposting of high density polyethylene packaging”.
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Leader : EDSON LUIZ FRANCISQUETTI
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MEMBRES DE LA BANQUE :
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EDSON LUIZ FRANCISQUETTI
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MARA ZENI ANDRADE
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ANA MARIA COULON GRISA
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ANA PAULA BILCK
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LAURA DE ANDRADE SOUZA
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RUTH MARLENE CAMPOMANES SANTANA
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Data: 30 août 2022
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When analyzing the gravimetric composition of a sanitary landfill, it can be observed that a large part of the material is formed by polymers from plastic bags, used to store organic waste. It is believed that exploring alternatives to mitigate the impacts resulting from the incorrect disposal of these wastes is necessary. Thus, it is possible to segregate them more easily in landfills, and the organic waste can be valued through composting or vermicomposting methods. In this way, an increase in the useful life of the landfill is obtained and there is a considerable gain from an environmental point of view. Therefore, the present work seeks to analyze the degradation and mischaracterization of commercial polyolefins in vermicomposting environments. Vermicomposting is a method of treatment and recovery of the organic fraction of waste that uses annelid species. In this study, Eisenia fetida species were used to determine their efficiency in the decomposition of polymeric material present in disposable polyethylene packaging. The biodegradation of polymeric materials was evaluated by infrared spectroscopy with Fourier transform, differential scanning calorimetry, optical microscopy, mechanical tensile test and mass reduction. After carrying out these tests, it was possible to observe degradation of the materials, as well as a gain in efficiency in the vermicompost environment. For this purpose, the vermicomposting and composting environments at temperature, humidity, hydrogen potential and carbon-nitrogen ratio were controlled using sensors. Therefore, this study effectively contributes to the scope of research regarding polymer degradation as it establishes the degradation efficiency in a vermicompost environment with commercial films.
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7
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MATHEUS DIONYSIO SLONGO
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EVALUATION OF POLYMERIC BLENDS WITH MATRIX OF POLYOXYMITYLENE FOR FURTHER ELASTOMER OVERINJECTION THERMOPLASTIC
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Leader : EDSON LUIZ FRANCISQUETTI
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MEMBRES DE LA BANQUE :
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ALEXANDRE LUIS GASPARIN
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ANA MARIA COULON GRISA
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ANA PAULA BILCK
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EDSON LUIZ FRANCISQUETTI
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JULIANA MACHADO FERNANDES DE MORAES
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LAURA DE ANDRADE SOUZA
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MARA ZENI ANDRADE
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Data: 5 oct. 2022
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Polyoxymethylene has good tensile strength, low friction coefficient, excellent dimensional stability. Polyoxymethylene has good tensile strength, low coefficient of friction and excellent dimensional stability. Thermoplastic elastomers have a rubbery, tacky surface and can be overmolding into a rigid substrate to increase friction and slip resistance. To obtain adhesion between the two materials, it is necessary that they are compatible and that the formation of polymeric blends is possible. The objective of this work is to evaluate the influence of the mechanical and thermal properties of polymeric blends with a polyoxymethylene matrix, after the addition of different percentages by weight of thermoplastic elastomer and the incorporation of a compatibilizing additive for subsequent overmolding of thermoplastic rubber and evaluation of adhesion between the materials. After the formation of the blends, it can be evidenced by the analysis of infrared spectroscopy by Fourier transform that there were interactions and miscibility between the materials, mainly in the samples that contained compatibilizing agent. The blends showed changes in morphology after scanning electron microscopy analysis of fractured samples in the impact strength test. The degree of crystallinity of the blends reduced with the incorporation of thermoplastic elastomer or the presence of the compatibilizing agent. The mechanical properties showed a reduction in tensile strength and elastic modulus with increasing percentage by weight of thermoplastic elastomer added to the mixture. The blends selected to receive the thermoplastic elastomer overmolding showed better adhesion in the mixtures that contained the compatibilizing agent, due to their chemical interactions and better interphase with the overmolding thermoplastic elastomer
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8
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CASSIANO RODRIGO DALBERTO
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INFLUENCE OF ZINC OXIDE ON MECHANICAL, THERMAL AND BIOLOGICAL PROPERTIES WHEN ADDED TO POLYPROPYLENE.
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Leader : EDSON LUIZ FRANCISQUETTI
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MEMBRES DE LA BANQUE :
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EDSON LUIZ FRANCISQUETTI
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MARA ZENI ANDRADE
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ANA PAULA BILCK
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FERNANDA TRINDADE GONZALEZ DIAS
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Data: 31 oct. 2022
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Polypropylene is one of the most consumed polymers in the world, due to its large production capacity in line with its low cost, which made it possible to use it in several applications. PP has characteristics that allow its use in injection, extrusion, thermoforming, rotational molding, and blow molding processes. The main application of polypropylene is in the food sector, representing 32% in products such as: packaging, lids, bowls, pots, bottles, and gallons. In the consumer goods sector, PP represents 17% of the market and is present in packaging and boxes. The addition of mineral fillers to thermoplastic polymers such as polypropylene (PP) has long been related to an attempt to reduce costs. Currently, with the technological development of the industry and new applications, the loads have gained greater importance and started to serve more than the economic objective, by adding improvements in the physical and chemical characteristics of the products. Recent studies show that zinc oxide can be added in polyolefins to improve mechanical properties, resistance to ultraviolet radiation and antimicrobial properties. The present work aims to evaluate the influence of the presence of zinc oxide on the mechanical, rheological, thermal, resistance to ultraviolet radiation and antimicrobial action of the compound formed by polypropylene and zinc oxide. PP compounds were prepared with commercial zinc oxide (ZnO) additives from two different suppliers, with different particle shapes and different average particle size (ZnO B and ZnO D) in the proportions of 0%, 1%, 3% and 5% in large scale. The samples were characterized by means of their rheological, physical, mechanical, thermal properties, bacterial activity and submitted to the accelerated aging test by UV degradation. The results showed that the content, size, shape and medium where the ZnO particles were dispersed interfere with the properties evaluated. The presence of zinc oxide affected the mechanical properties of the compounds, considerably increased the resistance to UV degradation of the polymer and gave the PP ZnO D compound the bactericidal property. In general, the compounds with the additive showed better results both in the physical-mechanical properties evaluated and in the biocide properties when compared to the pure material.
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9
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DIEGO CHIARELLO
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APPLICATION AND PERFORMANCE OF DLC THIN FILM IN THERMOPLASTIC INJECTION MOLD EXTRACTOR PINS
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Leader : ALEXANDRE LUIS GASPARIN
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MEMBRES DE LA BANQUE :
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ALEXANDRE LUIS GASPARIN
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DANIELA LUPINACCI VILLANOVA
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DANIEL AMORETTI GONCALVES
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LEANDRO LUÍS CORSO
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Data: 12 déc. 2022
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In this work, extractor pins of thermoplastic polymer injection molds, originally produced in AISI H13 steel and gas nitrided, were coated with a thin film of DLC (Diamond Like Carbon), making a tribological pair with extractor bushings of AISI P20 and AISI H13 steels quenched and tempered. The DLC thin film was deposited in a PECVD (plasma enhanced chemical vapour deposition) chamber with electrostatic confinement. A device that simulates the extraction system of an injection mold was used to test the wear behavior of the proposed pin-bushing pairs, as a function of the increase in the number of cycles. Different materials and lubrication conditions were tested, looking for more efficient alternatives to the current system that uses gas nitrided pins and white grease for molds as a lubricant. Optical microscopy and Scanning Electron Microscopy (SEM) were used for the microstructural characterization of the samples and analysis of the DLC layer. Wear on the pins was quantitatively evaluated by mass loss and by measuring the layer thickness in SEM after 100,000 cycles. Analysis of the roughness variation of the topography of the samples by SEM was carried out to verify the impacts of the wear test on the surface of the samples. The hardness and adhesion of the DLC film were measured through nanohardness and nanoscratch tests, respectively. In addition, the samples were analyzed by nanohardness, GDOES (glow-discharge optical emission spectroscopy), and the friction coefficient, by scratching test. The mass loss results show that for the samples without the use of lubricating grease, the wear rate was considerably lower. The pins with the least wear were those of the PS and HS sets, both without the use of grease, which showed a mass loss of 5,400 and 5,467 mg, respectively. These results prove the possibility of using DLC coated pins without the use of lubricating grease in injection mold extractor systems and that this still provides a considerable reduction in the wear rate. The DLC film presented a uniform layer, with an average thickness of 3.34 μm and no gaps between the film and the substrate after its deposition. The main wear mechanism for DLC lubricated systems was abrasion, due to the abrasive paste created with DLC particles and the grease. Therefore, the condition of pins with DLC without the grease had a better performance in the bench tests.
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