The Hyper Dip-Pulse pulsed welding process, found in Panasonic Tawers welding sources, stands out for its ability to control the transfer of molten material and the shape of the arc. To improve process efficiency and increase welding speed, this work aims to customize the Hyper Dip-Pulse current curve, with the purpose of reducing production cycle times and, consequently, increasing productivity in assembly lines involving welding. The work consisted of studying some variables of the process curve that influence the molten pool and solidified bead and evaluating the results, adjusting the parameters to maintain the quality of the welded bead. Welding is performed exclusively by means of a robotic arm and the base metal chosen for the study of this process was SAE 1020. Optical microscopy characterizations and hardness profile were performed on the weld beads. Vickers hardness tests started from the molten zone to the heat-affected zone, generating the hardness profile of the samples. After a detailed analysis, it was identified that the PPEAK -200, IP +200 and PFREQ +100 variables of the curve of this process presented positive characteristics after the proposed changes, making them candidates for new parameters to achieve the objectives of increasing the welding speed. The best configuration obtained, being the mixture of PFREQ+100 with IP+200, was determined based on the criteria established during the evaluation process, which consisted mainly of maintaining the original physical characteristics of the bead and the absence of defects pertinent to welding processes.

Cr-Ni stainless steels, such as AISI 304 and AISI 316, are widely used in the food industry due to their high corrosion resistance and ease of sanitation. In recent years, alternative alloys containing chromium and manganese (Cr-Mn) have emerged as more economical options due to fluctuations in nickel prices. The use of these alloys in the manufacturing of food processing equipment is recent and often occurs without proper sanitary assessment. Additionally, some Cr-Mn alloys are not standardized but are frequently marketed in Brazil as if they were equivalent to AISI 201 stainless steel. In order to assess the risks associated with the application of non-standard Cr-Mn alloys in the food industry, this study evaluated their performance compared to Cr-Ni stainless steel AISI 304, using a simulated food environment. The study focused on the release of metallic ions (Fe, Cr, Mn, and Ni) according to the protocol established by the Council of Europe (CoE). Ion release was analyzed using flame atomic absorption spectrometry. Corrosion tests were also conducted according to ASTM G31, with mass loss used as an evaluation parameter. The non-standard Cr-Mn alloy exhibited higher corrosion rates and greater release of metallic ions, especially iron and manganese, when compared to AISI 304. Based on the limits defined by the CoE protocol, it is concluded that the use of this non-standard Cr-Mn alloy poses a potential risk to food safety. Therefore, its application in the food industry is not recommended.

This study aims to analyze and compare the effects of active flux application in TIG (A-TIG) and plasma (A-PAW) welding processes, both applied to austenitic stainless steels, with a focus on improving weld penetration and the mechanical properties of the joint. Based on a review of previous studies and the experimental evaluation of the A-PAW process using SiO₂-based flux on AISI 316L steel plates (4 mm), it was observed that both processes with added flux promote arc constriction, resulting in narrower weld beads with greater penetration. In the case of A-PAW, the depth-to-width ratio increased by approximately 13%, the hardness of the fusion zone rose by 5.6%, and no significant changes were observed in tensile strength or toughness. In the A-TIG process, studies also indicate improvements in mechanical properties, attributed to the physicochemical effects of active fluxes—such as SiO₂ and TiO₂—on the arc and the weld pool. Microstructural analyses demonstrate stability in chemical composition and the absence of brittle phases in both processes. It is concluded that the use of active flux is an effective strategy to expand the applicability of stainless steel welding, especially for thicker materials, highlighting the importance of continued research aimed at optimizing flux compositions and expanding the industrial use of A-TIG and A-PAW techniques.

Currently, most electronic devices used in daily life contain printed circuit boards (PCIs), composed of conductive tracks and metallic areas for component mounting. When these boards incorporate light-emitting diodes (LEDs), they are applied in signaling systems for urban mobility and are commonly referred to as electronic panels. To ensure their durability in harsh environments, a protective coating known as conformal coating is applied, which safeguards components against weathering, mechanical stress, electrical discharges, thermal stress, and corrosion. This study evaluated the comparative performance of two silicone conformal coatings with distinct curing processes: an RTV system (room-temperature vulcanization, accelerated by convection oven) and a UV-cured system. A distinguishing feature of this research is the use of real operating boards, providing greater representativeness compared to studies based solely on laboratory samples. The analyses included hydrophobicity, adhesion, chemical resistance, corrosion, and UV degradation tests, using techniques such as Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), contact angle measurement, adhesion testing, accelerated aging, and salt spray exposure. FTIR analysis enabled the identification of functional groups in the formulations, while TGA highlighted the thermal stability of each coating. Combined, these methods provided an in-depth understanding of the chemical and physical behavior of the materials, allowing their properties to be correlated with performance under simulated real-world conditions. The results revealed distinct behaviors between the coatings, emphasizing that the selection of the most suitable system must account for specific operating conditions, as each material responds differently to humidity, temperature, and contaminant exposure.

The conventional water treatment process uses basic steps to transform raw water into drinking water. In the decantation stage, a large volume of sludge is generated with high variability and containing various particles that cause color and turbidity to the water. Proper disposal of the sludge produced is essential, as the greater the volume of waste is sought, the greater the volume of waste will be. The reuse of sludge from a Water Treatment Plant (ETA) in another activity or production process is fundamental due to the fate often given to this waste today, generally made available in natura in watercourses, causing a great negative impact. The ceramic industry presents itself as a way of inertizing any materials present in the sludge, by incorporating it into shaped pieces. The objective of this work is to evaluate the incorporation of ETA sludge into clay for the manufacture of conventional bricks and to verify the behavior of the samples in different proportions, temperatures and manufacturing pressures. The work was developed with sludge from a WTP in São Leopoldo, RS, and the clay used was from a brickworks located in the same municipality. 60 specimens were prepared with each of the clay/sludge proportions: 100/0; 97.5/2.5; 95/5; 90/10; 80/20. For half of them, a compaction pressure of 25 MPa was used and for the other half, 50 MPa was used to form the bricks. Every 10 specimens of each amount of sludge incorporation and each pressure used were burned at 900, 1000 and 1100 °C. The results are presented in tables and graphs and indicate that up to the incorporation of a fraction of 10% of sludge in the ceramic mass, it is possible to use conventional bricks made for internal use or without exposure to humidity or rain. At the end, along with the conclusions, some recommendations are presented for the economic, environmental and social sustainability of the water treatment production process.

Nowadays, the packaging industry has been striving to meet the increasing market demands for sustainable and active materials. In this scenario, the use of starch becomes promising, especially when combined with essential oils, which have antimicrobials and antifungals properties. However, the volatility of these substances represents a challenge. Therefore, this study aimed to evaluate two methods of incorporation of thyme essential oil into cassava starch foams, focusing on the characterization of their physical, chemical, morphological, mechanical, thermal, and microbiological properties. Initially, the minimum inhibitory and minimum bactericidal concentrations of the essential oil were determined. Then, this substance was incorporated into sodium montmorillonite clay, using the emulsion method. After that, the starch foams were produced by mixing with a magnetic stir, followed by the thermoforming. The addition of the essential oil occurred through the incorporation of the clay hybrid in the formulation and the application of this substance on the surface of the foams.  Minimum inhibitory and bactericidal concentrations of 12,5 e 25 %(v/v), respectively, were verified. The highest amount of incorporated essential oil (~18,88%) was reported for the clay sample produced with Tween 80. The loss of part of the essential oil was verified through the thermogravimetric analysis, when simulate the starch foam processing conditions. However, the presence of this substance was detected in the E-HB through FTIR, after thermoforming. When comparing OET incorporation techniques, E-HB showed greater thermal stability. However, the E-SUP-25 sample presented smaller and more closed air bubbles, greater impact resistance, and lower water absorption rates compared to the E-HB. In the microbiological analysis, this sample presented inhibition zones of 2,82 ± 0,22; 2,85 ± 0,15, and 2,39 ± 0,22 cm against S. aureus, S. enterica and E. coli. Comparing E-NaMt and E-HB samples, the presence of essential oil in the interlayer space seemed to affect the interaction between starch and the clay. Therefore, among the methods analyzed, surface application was the most effective, being a promising alternative for application in food packaging, especially for products containing low water content.

One of the most commonly used processes in industrial manufacturing is machining. This process is responsible for high waste generation, with chips being the most significant portion. Due to the impossibility of completely eliminating industrial waste production and with the aim of adding value to them, promoting more sustainable productions with lower environmental impacts, the reprocessing of waste becomes interesting, applying them in new manufacturing processes other than just casting. One advantage of machining chips is the possibility of being reprocessed and transformed into metallic powders, allowing their reuse in the production of new parts, mechanical components, among other goods of interest, through processes like powder metallurgy. It is through this technique that excellent economic results can be obtained by producing metallic powder from machining chips, adding value to them. Based on these points, this research aimed to analyze the evolution of the fragmentation of machining chips subjected to the milling process in a ball mill. For this purpose, portions of machining chips from materials such as SAE 1045 steel and AISI H13 were subjected to the milling process in a ball mill for periods of 20, 40, and 80 hours. After the completion of each milling period, the residual chips were separated and characterized regarding morphology, size distribution, microhardness, and microstructure. In addition to characterizations, the grinding efficiency calculation was applied to the residual chips. As for the obtained metallic powders, techniques such as scanning electron microscopy (SEM), laser diffraction granulometry, flowability, and compressibility were applied. Regarding the residual chips, it was noticed that, for both materials, the milling process used was able to fragment them into smaller particles than the original ones, and there is an influence of the milling time on the particle size. It was observed that, for SAE 1045 steel, there was a significant alteration in the shape of the microstructural grains and an increase in microhardness. However, for H13, there were no changes in these aspects. Regarding the produced powders, fine and superfine powders were obtained for both materials, with a predominant particle size range of 1 to 25 µm. Through scanning electron microscopy, it was identified that SAE 1045 steel produced some flakes-shaped particles for the 20-hour period, and for the other milling times, the predominant shape was polygonal. As for AISI H13 steel, the particles varied between spherical and polygonal shapes. It was not possible to confirm if these shapes would be the standard because, being very fine, these powders ended up generating many agglomerates. Flowability analysis characterized the powders of both materials with free-flowing behavior, and finally, compressibility testing showed that the powders exhibit similar behaviors during sample compression. After verifying the amount of residual chips present at the end of each milling period, it was found that the grinding efficiency was low for both materials, however, it was higher for SAE 1045 steel. The presence of metallic powders within the same particle size range was also verified, even for shorter milling periods. It is concluded from this research that, despite representing low efficiency, the milling process using a ball mill is capable of processing machining chips and turning them into smaller particles to obtain metallic powders with superfine dimensions, and these particles can serve as raw material for the powder metallurgy process, especially for metal injection molding, given the characteristics of the obtained material.

The monobloc forged tubular beams, manufactured of seamless steel tubes in Brazil, are feasible due to the current Exchange rate and high costs of importation of competitive axle beams. The search for competitiveness of national products is necessary to guarantee the growth and strength of our transformation industry. This work consists on the characterization of forged seamless steel tubes of the steel grade FB70 without the final normalization heat
treatment processo simplify the manufacturing process. The approval of the axle beams without the heat treatment was done upon laboratory tests for the mechanical properties to guarantee the engineering specifications. The results of the yield strength of 490 MPa, the tensile strength of 610 MPa, alongation of 20% and Rockwell B hardness of 87 HRB were fully attended based on a typical cooling curve, as well as the fatigue test.

The search for materials from renewable sources, low cost and high performance that replace the materials currently used, are aligned with the increased concern about the environment. In this way, studies about preparing of polymeric composits, reinforced with natural fibers, that provide low cost, high performance and favorable to the environment are gaining prominence. The addition of fibers mainly influences the mechanical caracteristics of composites, when looking for aggregation of other properties, the addiction of nanomateriais is recommended. One of the nanomateriais most studied nanomaterials is montmorillonite clay (MMT), which provide an improvement in mechanical properties, in addiction to affecting the morfological termal properties, among others. Clays are hydrophilic in nature. In this way, the treatments on its surface are indicate, to improve its dispersion, one of the most used techniques is silanization.  In this project intends to develop polyester matrix composites molded by resin transfer technique (RTM), reinforced with ramie fiber and MMT clay, to investigate its performance against the requirements necessary for application in automotive panels.  At this first moment the behavior of the silanization in an organomodified clay was analyzed, as well as its properties in the manufacture of nanocomposites, molded using the casting technique. For this a mixture of silane (MPS) and anhydrous alcohol, were dripped into a mixture of modified organo clay and anhydrous ethanol previously mixed with the aid of a mechanical stirrer; Then the mixture of etanol and MPS was dripped together with the mixture of clay and etanol, remaining under magnetic stirring at 80 °C for 24 hr. After centrifugation, the clay was dried, crushed and sied, in a sieve with na opening of 53 µm. The preparation of nanocomposites was carried out by homogenizing the resin with 3% by weight of clay, with the aid of a mechanical stirrer, followed by an ultrasound bath to remove the bubbles. Finally the initiator was added and the resin was poured into previously prepared silicone molds. The clays were analyzed using FTIR, DRX and TGA techniques, where it was possible to confirm the silane graft in the clay. Rheological analyzes were carried out in the purê resin, and with incorporation of clay particles and, finally, FTIR, DRX, mechanics, and dynamic mechanycs, analyzes were performed, which indicated the incorporation of clay with the polyester matrix, in addition to an increase in strength in nanocomposites prepared with clay compared to pure resine.  Therefore, it is concluded that the method used promoted the silanization of the clay, in addition to demonstrating that the incorporaton of clay in a polyester matrix, promotes an improvement in its mechanical and dynamic mechanics properties. Despite the result between the nanocomposites, don't show great differences, studies demonstrate that silanes promote a better interaction between the polyester resin and natural fibers, thus justifying their use in the continuation of the project.

This work provides a comprehensive analysis of the application of machine learning techniques in Materials Engineering, highlighting their role in addressing challenges related to material development, property prediction, and process optimization. The research is structured into two scientific articles: the first presents a systematic literature review of studies published between 2015 and 2023, identifying key techniques such as neural networks and deep learning, as well as the most benefited subfields, including metallic materials, composites, and nanomaterials. The second article focuses on a case study applying artificial intelligence to optimize the sustainable manufacturing of austempered ductile iron. The results show that machine learning techniques can reduce costs, accelerate material development timelines, and improve the accuracy of property predictions. However, challenges such as data quality and the need for standardization still limit their practical implementation. It is concluded that the integration of materials science with computer science is essential for advancing the field and fostering the broader adoption of artificial intelligence-based technologies.

Among the various types of discarded materials, electronic waste (ewaste) has been exponentially increasing in recent years due to its perceived obsolescence within a short time frame. In this context, the objective of this study is to evaluate the feasibility of producing a filament for use in 3D printing using polymer residues derived from CRT monitor and television casings. Spectroscopic characterization of the e-waste revealed differences in Polymer identification in the casings compared to the results obtained from the analysis. Thermal and rheological properties were found to be similar to virgin Acrylonitrile Butadiene Styrene (ABS). The ABS residues were extruded under the same conditions as the virgin material, yielding satisfactory results. However, the postextrusion cooling method introduced high porosity into the filament. The fused deposition modeling (FDM) printing process of the test specimens proved to be efficient using the recycled filament, although porosity was observed in the printed parts. Overall, the printed parts using the recycled filament exhibited inferior mechanical properties compared to those printed with virgin ABS. The identified voids in the print had the most significant influence on the mechanical response of the samples produced with the recycled filament, resulting in na approximately 83% reduction in impact strength. The filament produced from ewaste is suitable for 3D printing applications that require good dimensional tolerance without the need for high mechanical properties.

The present study presents a surface coating with polytetrafluoroethylene (PTFE) and molybdenum disulfide (MoS2) on the cutting edges and on surfaces of the channel of Auger Bits twist drills used for drilling in wood, mainly Pinus elliottii, widely used in civil construction. The chemical characterization of the functional groups of the coating layer was carried out by Fourier transform infrared spectroscopy (FTIR), the tool life evaluation through bench tests, and the latter torque variation during the drilling process. The films and substrates' hardness were verified by Vickers durometer, and the metallography was performed to identify the drill microstructure and the film thicknesses. All analyzes were performed comparatively between the variations of samples with PTFE, MoS2, and uncoated standard samples. The tests were carried out in the laboratory with controlled parameters after the characterization of the samples concerning dimensional, heat treatment, and coating applied. In the analyses compared to the uncoated samples, the drills with PTFE obtained reductions of up to 38% in roughness, reduced drilling torque in the tip and channel region, required less power and energy from the screwdriver obtained low levels of layer peeling. On the other hand, the MoS2 samples showed a roughness reduction of up to 30% in some regions. Still, an increase of 66% in the channel region, presented an increase in drilling torque of more than 22%, an increase in consumed power of 16% in the channel region, and an 18% increase in energy consumption, in addition, to completely peeling off the coating layer in the cutting edges. The torque in samples with PTFE was lower than MoS2 in all cut regions of the drill. The core drills microstructures were martensitic, and due to the coating process, the core hardness on the HRC scale decreased. In general, PTFE-coated samples showed the best results when compared to MoS2 but, actually, had been observed a changing in the drills performances, which still needs to be further evaluated to improve tool life

In recent times, the issue of plastic recycling has become one of the leading issues of environmental protection and waste management. Polymer materials are found applied in many areas of daily life and industry. Along with their extended use, the problem of plastic waste appeared because, after withdrawal from use, they became persistent and noxious wastes. The possibility of reusing polymeric materials enables waste utilization to obtain consumable products. The 3D printing market is a well-growing sector. Printable filaments can be made from various thermoplastic materials, including those from recycling. This paper studies the thermal-mechanical properties of recycled polylactic acid (PLA) material filaments obtained from 3D-printed specimens. The analysis was first with the virgin filament (PLA N) and, subsequently, two recycling cycles (PLA 1 and PLA 2). There were thermal properties evaluations for the three processing types, as follows: differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and tensile test for both specimens and filaments. The glass transition temperatures (Tg) remained at their typical values. The same happened with the melting temperature (Tm). In the TGA, the PLA thermal stability remained constant. The FTIR presented the functional groups unaltered for the recycled samples. In the second filament recycling, the tensile strength decreased by 26%, and the maximum strain was 40%, compared to PLA N. The same occurred to PLA 2 specimens; the maximum stress and strain decreased by 45% and 31%, respectively. In terms of crystallinity, this presented a variation of 86% of the virgin material for the second recycling cycle, which correlated to tensile strength shows a weakness in the PLA recycled structure, decreasing the strain until the fracture and the tensile strength.

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.

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).

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.

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

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.

Metal structures made of carbon steel are widely used in civil construction and are susceptible to corrosion. In this sense, improving the strength of the material is essential to prevent deterioration of the metallic structure. One of the ways to prevent the corrosive process of steel from occurring is through corrosion inhibitors. The study of corrosion inhibitors from renewable and biodegradable natural resources becomes relevant for being an environmentally friendly, efficient and low-cost method for anticorrosive protection. Thus, this work proposes to evaluate the inhibitory effect of the natural extract of bergamot bark (Citrus reticulata) against the corrosive process of carbon steel ASTM A36. For this purpose, mass loss tests were performed on specimens by immersion in a corrosive medium of HCl, combined with electrochemical techniques. In addition, adsorption isotherms were built in order to determine physicochemical parameters related to the adsorptive process. The results obtained demonstrate a high efficiency of inhibition against corrosion compared to the process induced in the absence of the inhibitor, and the inhibition increases with the relative concentration of the extract. Furthermore, the greatest inhibition efficiency was observed after 72 hours of contact, decreasing with longer exposure times. Thus, the results obtained suggest that the bergamot extract has the potential to be used in the protection against corrosion of carbon steel ASTM A36 in an acidic medium.

Poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) is fluoropolymer that has an extensive application area, ranging from medical and aerospace industry, to household utensils. As a result, large volumes of waste (or residues) are generated during its processing, and its reincorporation is necessary not only because of the environmental appeal, but also because of its economic value. The objective of this study is to evaluate the viability of reincorporation of PFA’s residues, generated by the extrusion process, in to neat PFA (PFAv). The results showed that the reincorporation of up to 10% of reprocessed PFA (10PFAr) proved to be adequate to produce extruded tubes. In this sample, the thermal and chemical properties appeared to be stable, in addition it has not been found significant differences in the mechanical properties evaluated in comparison with the neat PFA sample. Besides that, higher concentration of PFAr (˃50%) promoted a reduction in tensile strength and elongation at break, in addition an increase in elastic modulus and hardness. The samples showed a yellowing effect, which was more evident with the increase of the PFAr content.

Glass is a widely used material, however, it is far from being recycled in its entirety. A good alternative to glass recycling is its incorporation in ceramic masses, since in these glass acts as a flux. Several studies investigate the addition of residual glass in ceramic mass for the production of bricks, tiles, blocks and even porcelain tiles, but there are no studies that deal with the addition of residual glass in an interlocked clay floor. Therefore, the present study proposes the incorporation of residual glass in interlocked clay pavement characterized by its rustic appearance and natural coloration. To this end, the present research investigates the physical and mechanical behavior of specimens as a function of glass residue composition and firing temperature. Three ceramic paste formulations were used. One is composed entirely of kaolin clay (100C), the second has 60% kaolin mass and 40% glass waste (60C40WG), and the third is 40% kaolin and 60% glass waste (40C60WG). The samples were burned at 900, 950 and 1000 ºC. The properties of shrinkage, water absorption, flexural strength (RMF) and compression (RMC), density and chemical attack were evaluated. The morphology and composition were analyzed by scanning electron microscopy (SEM) and dispersive energy spectroscopy (EDS). In addition, the visual aspect of kaolin and red clay pavements with colorless, green and amber glass additions was investigated. StatPlus software was used for variance analysis and tukey test. Based on the results, it can be concluded that ceramic masses with incorporation of 40 and 60% of glass dust burned at 950ºC are technically suitable for the manufacture of interlocked clay floor for industrial floor application, light traffic and pedestrians In addition, parts formulated with 60% glass waste and burned at 950 ° C still fit for use in heavy vehicular traffic.