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Niemczewska-Wójcik, Magdalena, i Artur Wójcik. "Stereometric and Tribometric Studies of Polymeric Pin and Ceramic Plate Friction Pair Components". Materials 14, nr 4 (9.02.2021): 839. http://dx.doi.org/10.3390/ma14040839.
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Two complementary approaches should be used for the full characterisation of friction pair components. The first approach consists of stereometric studies of machined as well as worn surface topography of the friction components with multiple measurement methods used. The second approach, tribometric studies, enables the tribological characteristics of the friction pair. This work presents the complete characterisation of polymeric pin and ceramic plate friction pair components based on studies with the use of three research instruments: an interference microscope, a scanning electron microscope and a tribological tester. The results of the studies showed that the same treatment conditions used for different but similar ceramic materials did not provide exactly the same characteristics of both the machined and worn surface topography. Moreover, the results showed that the material properties and machined surface topography of the ceramic component significantly affected the friction coefficient and linear wear as well as the wear intensity of the polymeric component. Connecting the two approaches, stereometric studies and tribometric studies, allowed for a better identification of the wear mechanism of the polymeric pin (i.e., abrasion, fatigue and adhesion wear) and the kind of wear products (polymeric material).
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Prajapati, Deepak K., i Mayank Tiwari. "Use of Artificial Neural Network (ANN) to Determining Surface Parameters, Friction and Wear during Pin-on-Disc Tribotesting". Key Engineering Materials 739 (czerwiec 2017): 87–95. http://dx.doi.org/10.4028/www.scientific.net/kem.739.87.
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In tribological analysis of machine elements (such as gears, ball/roller bearings etc.), surface roughness plays very important role, ultimately it affects the friction coefficient, wear, rolling contact fatigue (micro pitting) and other failure mechanisms. Surface geometry and topography changes with time (number of cycles) during rolling/sliding motion of contacting surfaces. So, it is important to show the variation of surface topography parameter during wear process. This work presents the evolution of roughness parameters, wear and friction coefficient during pin-on-disc tribotesting under dry condition. The test is performed using pin on disc apparatus under room temperature condition. The pin (25mm long, 6mm diameter) is made of medium carbon steel (AISI 1038) whereas the disc (165mm diameter, 8mm thickness) is made of high carbon steel (SAE 52100). This works demonstrates the potential of Artificial Neural Network (ANN) for prediction of roughness parameters, friction coefficient and wear coefficient. Experimental results obtained from wear testing are compared with those obtained using artificial neural network (ANN) analysis. A very good agreement in results suggests that a well trained neural network is capable to predict the parameters in wear process.
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Chlipala, Mateusz, Johannes Schneider i Volker Schulze. "Experimental Analysis of Microstructured Steel Surfaces for Wet Tribological Applications in the Low Velocity Regime". Conference Papers in Science 2015 (5.05.2015): 1–7. http://dx.doi.org/10.1155/2015/387830.
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The surface topography plays an important role in the design of a function-optimised surface. Therefore, the influence of topography with microsized structures produced by laser surface texturing (LST) is experimentally examined under lubricated sliding conditions. The structured specimens were made of AISI 51200 (DIN 100Cr6) hardened to about 800 HV. Concerning the requirements of tribological testing without any debris caused by the preprocessing, the structuring was carried out using a picosecond laser system (Trumpf TruMicro) with 6 ps pulse duration. A laboratory pin-on-disc tribometer (Plint TE-92 HS) was used for the tests, which were run under wet conditions with counterbodies made of bronze and steel at a nominal contact pressure of up to 4 MPa and sliding speeds between 0.04 and 2.0 m/s. Furthermore, start-stop cycles with accelerating and decelerating shares were used to simulate an automotive start-stop system. In the tribological experiments, a significant reduction of the friction coefficient was observed compared to sliding pairs without microstructured pin surfaces. Whereas no measureable wear occurred on the steel pins and discs, the bronze discs showed a significant amount of wear and the microstructures on the pin surfaces mated against bronze discs were almost completely filled with wear debris.
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Syahrullail, Samion, i Noorawzi Nuraliza. "Effect of Surface Roughness Parameters and Surface Texture for Reduced Friction". Applied Mechanics and Materials 695 (listopad 2014): 572–75. http://dx.doi.org/10.4028/www.scientific.net/amm.695.572.
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The aim of the present research was to investigate the possibility of contact surfaces with reduced friction using surface roughness analysis. For this purpose, various aluminum pin samples with different lubricant using different sliding speed values were prepared. To evaluate influence of roughness parameters on friction and wear, lubricated pin-on-disk tests were carried out under different speed contact conditions. Test results show that surfaces with high values surface roughness results in reduced friction. To investigate the effect of surface topography on surface roughness parameters and consequently on friction, real roughness profiles were virtually altered to achieve virtually textured surfaces.
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Edachery, Vimal, V. Swamybabu, H. Rajneesh i Satish V. Kailas. "Friction, Scuffing and Transfer Layer Formation in Lubricated Sliding of EN31 Steel and Tungsten Carbide (WC): Surface Topography Effects". Key Engineering Materials 901 (8.10.2021): 182–86. http://dx.doi.org/10.4028/www.scientific.net/kem.901.182.
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Surface topographies play a critical role in controlling friction, surface damage and transfer layer formation in engineering applications; hence understanding this is of great importance. In this work, experimental studies were carried out to understand the influence of surface topography on friction, scuffing and transfer layer formation in completely immersed lubricated sliding interactions. For this, sliding experiments were carried out in sphere on flat configuration using EN31 steel flats and Tungsten Carbide pin countersurface. Perpendicular and parallel surface topographies were induced onto the steel flats. Experiments were conducted at high normal loads of 1000N, 2000N and 3000N. The results show that Surface topography has a significant influence on the frictional response. When the topography directionality was perpendicular to the sliding direction, scuffing was observed only at a high load of 3000N. A ‘peak friction’ was also observed during the occurrence of scuffing. When the directionality in topography was parallel to sliding direction, scuffing and surface damage occurred from 2000N itself, accompanied by a high amount of transfer layer formation. This can be attributed to the directionality of parallel topography, which displaces away the lubricant during sliding interaction, creating metal-to-metal contact and hence leading to scuffing and higher transfer layer formation.
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Supadee, Laddawan, Santi Chatruprachewin, Chaba Suriya-Amaranont i Wisut Titiroongruang. "Corrosion Characterization of High Moment Magnetic Material Coated with Diamond-Like Carbon". Advanced Materials Research 811 (wrzesień 2013): 171–76. http://dx.doi.org/10.4028/www.scientific.net/amr.811.171.
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In order to increase data storage density of hard drive, DLC overcoat thickness was decreased to allow read/write head to come closer to magnetic alloy of the disk, andwith maintaining the main purpose of the overcoat to provide good corrosion and mechanical protection for the underlying magnetic recording film under unfavorably environmental conditions and occasional reactions. Base on that the edges of topography will be weak point for deposition films cause of shadow effect during the process, its hard that deposition atomic will stay at the concave and convex of topography. DLC coverage performance at the edge of 3D topography becomes high sensitive with limited DLC films thickness. Currently the 3D profile of magnetic material that needs to protect with DLC, is about 2 nanometers with subnanometres DLC thickness. The enormous of data shrew corrosion pattern was usually happened at the edge of topography. Thus, the accelerated test or indirect methodology was applied for DLC integrity. This investigation was explore the methodology to verify the weakness of DLC films especially at the topography edges which is difficult for any direct metrology tools can pursue. With pore resistance, which related to the film structure, the electrochemical impedance indicated that DLC/Si3N4 is a suitable choice to against corrosion. However topography surface influence to DLC coverage. Controllable surface for DLC deposition also needed well defined. Two types of step height was created as 1 nm and 2 nm on (100) silicon substrate. The 20Å DLC film thickness was deposited on the silicon substrate with promised technique, Filtered Cathodic Vacuum Arch (FCVA). After this process the aluminum (Al) was deposited on the surface of DLC film by using evaporation technique. The silicon substrate was driven to Al surface thro pin holes on the DLC film at 577OC. To detect the pin holes on the DLC film, the aluminum layer was removed by using wet etch chemical process. The SEM image indicates that the square pitting at the edge of DLC film obtained for 2nm step height was around 2nm depth. The latest experiment in this investigation to characterize 2.3 T magnetic moment material degradation with DLC/Si3N4 coating, was performed with electrochemical impedance spectroscopy and AFM. The material with DLC overcoat after exposed to H2SO4 for 30 min, polarization resistance was increased for 2 times from uncoated material. Alternative charge transfer capacitance was reduced as desirable charge current.
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Thompson, R., J. Song, A. Zheng i J. Yen. "Cartridge Case Signature Identification Using Topography Measurements and Correlations. Unification of Microscopy and Objective Statistical Methods". Izvestiya of Saratov University. Economics. Management. Law 12, nr 3 (2012): 60. http://dx.doi.org/10.18500/1994-2540-2012-12-3-60-60.
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A comparison microscope employing the standard optical comparison method and confocal microscopy with subsequent cross correlation topography analysis were used to correctly identify cases fired from a set of ten (10) consecutively made pistol slides. The mathematical identifications were based on the breech face impression without the firing pin aperture shear marks. Fifteen (15) unknown cartridge cases were compared to test fired cartridge case sets from the consecutively manufactured slides.
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Ohyanagi, Takasumi, Chen Bin, Takashi Sekiguchi, Hirotaka Yamaguchi i Hirofumi Matsuhata. "EBIC Analysis of Breakdown Failure Point in 4H-SiC PiN Diodes". Materials Science Forum 615-617 (marzec 2009): 707–10. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.707.
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The breakdown failure points in the 4H-SiC PiN diodes were analyzed by the electron beam induced current (EBIC). We focused on the failure, which showed the avalanche breakdown, and we determined the failure points by an emission microscopy. We observed the basal plane dislocation around the failure point and at measured temperatures below 200K we found the dark spots in the EBIC. However, in the X-ray topography image, no spots were found around the dislocations. We therefore think that these spots originated from the metal contamination. The electric field was multiplied due to a permittivity change, and this multiplication caused the avalanche breakdown.
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Liu, Chao Xun, Shi Hong Lu, Wei Miao, Pan Feng Song i Tian Rui Wu. "Experimental Study on Ultrasonic Shot Peening Forming and Surface Properties of AALY12". Advanced Materials Research 1094 (marzec 2015): 339–42. http://dx.doi.org/10.4028/www.scientific.net/amr.1094.339.
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Ultrasonic shot peening (USP) on AALY12 sheet was studied. Several parameters (arc heights, surface roughness, surface topography and micro hardness) with different USP process parameters were measured. The research proposes that radius of curvature of shot peened sheet increases with time and electric current decreasing, while increases with pin diameter increasing, and radius of curvature reaches a saturation level after a specific processing time and electric current. An empirical model of the relationship between radius of curvature and pin diameter, electric current, time was also obtained. The research shows that the increment of surface and vertical micro hardness of material is more obvious with longer time and higher value of electric current, which can be up to 20% and 28% respectively.
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Shin, Kwonsik, Dongsu Kim, Hyunchul Park, Minkyung Sim, Hyunwoo Jang, Jung Inn Sohn, Seung Nam Cha i Jae Eun Jang. "Artificial Tactile Sensor With Pin-type Module for Depth Profile and Surface Topography Detection". IEEE Transactions on Industrial Electronics 67, nr 1 (styczeń 2020): 637–46. http://dx.doi.org/10.1109/tie.2019.2912788.
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Chen, Ze Yu, Ya Fei Liu, Hong Yu Peng, Qian Yu Cheng, Shan Shan Hu, Balaji Raghothamachar, Michael Dudley, Stephen A. Mancini, Seung Yup Jang i Woongje Sung. "Analysis of Basal Plane Dislocation Motion Induced by p+ Ion Implantation Using Synchrotron X-Ray Topography". Defect and Diffusion Forum 426 (6.06.2023): 71–78. http://dx.doi.org/10.4028/p-4mo61y.
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Multiple PIN diodes with junction termination extension (JTE) were fabricated on 4H-SiC wafers with 10 μm thick epilayers by ion implantation with various dosages of Al ions at room temperature (RT) and high temperature (600 °C). The subsequent annealing process was conducted at 1650 °C for 10 minutes to activate the dopant atoms and recover the lattice damages introduced by the implantation. Synchrotron X-ray topography was used to characterize the defects in the devices, and it is observed that basal plane dislocations (BPDs) were generated during the annealing process from the boundaries between the high (P+) and low (P-) doping concentration in devices implanted with relatively high doses at RT. Further, topographs also manifest motion of BPDs due to implantation-induced stresses, where BPDs with opposite sign Burgers vectors move in directions accommodative of nature of stress (tensile/compressive). On the other hand, generation of BPDs due to implantation was not observed in devices implanted either at relatively low dosages at both temperatures or relatively high dosages at high temperature. Measurements of blocking behaviors of devices illustrate that devices with higher densities of process-induced BPDs yield higher leakage currents.
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Harmawanto, Agung Gagah, Yosef Cahyo Setianto Poernomo i Sigit Winarto. "PERENCANAAN ALTERNATIF GEOMETRIK DAN METODE PELAKSANAAN RUAS JALAN NGRAHO – NGAWI STA.14+500 - STA.19+500". Jurnal Manajemen Teknologi & Teknik Sipil 2, nr 2 (6.11.2019): 179. http://dx.doi.org/10.30737/jurmateks.v2i2.510.
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Ngraho - Ngawi Sta. 14 + 500 – Sta. 19 + 500 highway is a collector connecting Bojonegoro to Ngawi Due to high traffic density, a road geometric Development is in need. The objective of this final project is to plan a good alternative geometric design-safe, comfortable, and easy to access. The required data were of topographic map and the road geometric design was based on the “Tata Cara Perencanaan Geometrik Jalan Antar Kota” General Works Standart No. 038/TBM/1997. The calculations result in Class 2 – lane collector road with one lane of 3 m wide having 8 turns, twists PI1 Spiral-Spiral, PI2 Spiral-Circle-Spiral, PI3 Spiral-Circle-Spiral, PI4 Spiral-Circle-Spiral, PI5 Spiral-Circle-Spiral, PI6 Spiral-Circle-Spiral, PI7 Spiral-Circle-Spiral, and turn PI8 Spiral-Spiral shape PPV PPV 1 concave and 2 convex, concave 3 PPV.Jalan provinsi ruas Ngraho – Ngawi Sta. 14+500 – Sta. 19+500 adalah jalan kolektor yang menghubungkan kota Bojonegoro - Ngawi. Karena lalu lintasnya padat, maka perlu diadakan peningkatan geometrik jalan. Dalam laporan akhir ini penulis membuat perencanaan alternatif desain geometrik jalan yang baik-aman,nyaman, dan mudah diakses oleh pengguna jalan. Data yang digunakan adalah peta topografi dan perencanaan desain geometrik jalan berpedoman oleh “Tata Cara Perencanaan Geometrik Jalan Antar Kota” Standar Bina Marga No.038/TBM/1997. Dari perhitungan diperoleh hasil sebagai berikut: kelas jalan kolektor dengan 2 lajur 1 jalur dan memiliki lebar 3 m, 8 tikungan, tikungan PI1Spiral-Spiral, PI2 Spiral-Circle-Spiral, PI3 Spiral-Circle-Spiral, PI4 Spiral-Circle-Spiral, PI5 Spiral-Circle-Spiral, PI6 Spiral-Circle-Spiral, PI7 Spiral-Circle-Spiral,dan tikunganPI8 Spiral-Spiralbentuk PPV 1 cekung dan PPV 2 cembung, PPV 3 cekung.
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Almansour, Haidara, Johann Jacoby, Heiko Baumgartner, Marie K. Reumann, Konstantin Nikolaou i Fabian Springer. "Injury of the Tibial Nutrient Artery Canal during External Fixation for Lower Extremity Fractures: A Computed Tomography Study". Journal of Clinical Medicine 9, nr 7 (14.07.2020): 2235. http://dx.doi.org/10.3390/jcm9072235.
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The tibial nutrient artery (TNA) is the major diaphyseal artery of the tibia supplying two thirds of the inner osseous cortex. Hence, iatrogenic injury of the TNA endangers the integrity of the tibial blood supply and may compromise fracture healing. The incidence of its injury in the setting of external fixation for lower limb fractures has not been previously investigated. The aim of this study was to evaluate the incidence of TNA injury in the context of external fixation and to characterize the topography of the fixator pins in relation to the TNA canal (TNAC). Patients who underwent external fixation for distal femoral fractures and for tibial (proximal, shaft, and distal) fractures and had a postoperative computed tomography study were retrospectively included. The following parameters were retrieved: 1) Pin characteristics (orientation and cortical position of the pins), 2) The anatomic relationship between the TNAC and external fixation pin (topography above/below and at the level of the TNAC, and the distance between the pin and medial tibial plateau and/or the medial malleolus), and 3) The incidence of TNAC injury (complete/partial disruption of TNA lumen). A total of 105 patients with 214 tibial pins were analyzed. In 27 patients (26%), the TNAC was completely injured by the pins of the external fixator. In 13 patients (12%), the TNAC was partially injured. Of the 214 analyzed pins, 85 pins (40%) were located at the level of the TNAC (the TNAC and the pin are seen on the same axial slice). Most pins that were applied at the level of the TNAC belonged to a knee-bridging external fixator. Of those, ninety-three percent of the pins were anteromedially applied according to published surgical guidelines. Six percent of the pins were applied through the tibial crest and 1% anterolaterally. Of those 85 pins, 42 pins (49%) injured the TNAC at least partially. Based on the analyzed pins and the incidence of partial and complete injury of the TNAC, we observed that the tibial segment at which the tibial nutrient artery is endangered was located approximately (95% CI: 13–15 cm) from the medial tibia plateau and (95% CI: 22–25 cm) from the medial malleolus. Thus, TNAC injury by external fixation pins in the context of lower limb fractures can be considered common. Almost half of the pins applied at the middle third of the tibia injured the TNA, despite adherence to published surgical guidelines for external fixation. When possible, pin application at the middle third of tibia should be avoided to circumvent iatrogenic injury of the TNA and to safeguard tibial blood supply.
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Trzepieciński, Tomasz, Anna Bazan i Hirpa G. Lemu. "Finite Element Modeling of Frictional and Material Anisotropy During Forming of Steel Cylindrical Cups". Applied Mechanics and Materials 789-790 (wrzesień 2015): 3–6. http://dx.doi.org/10.4028/www.scientific.net/amm.789-790.3.
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The article presents a method of determining the anisotropic friction model in metal forming using multilayer artificial neural networks based on experimental data obtained from the pin-on-disk tribometer. The experimental results show that the friction coefficient depends on the measured angle from the rolling direction and corresponds to the surface topography. Both the friction and material anisotropic models were implemented into a finite element (FE) model built using the commercial FE-package ABAQUS/Standard. When both the material and friction anisotropy are taken into account in the finite element analysis, this approach gives the most approximate numerical results to real processes.
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Dzierwa, Andrzej. "Influence of Steel Surface Preparation Method on Topography and Tribological Behaviour in Dry Sliding Conditions". Key Engineering Materials 674 (styczeń 2016): 265–70. http://dx.doi.org/10.4028/www.scientific.net/kem.674.265.
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Tribological tests were conducted using a pin-on-disc tester. In the experiment, a steel disc of hardness 40 HRC was put in contact with a steel ball of hardness 62 HRC. Disc samples were prepared in order to obtain very similar values of the Sa parameter, smaller than 0.5 μm. Different methods of preparing smooth surfaces were used. Dry tests using similar contact conditions were carried out. During tests, the friction force was monitored as a function of time. Wear of discs and balls was measured after the test using white light interferometer. In order to decrease variation of the experimental results, during tests the wear debris was continuously removed from the disc surface. It was shown that type of treatment play a role on tribological behavior of sliding pairs.
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Knopp, André, i Gerhard Scharr. "X-ray photo-electron spectroscopic studies of cryogenic and plasma surface-treated z-pins". Journal of Composite Materials 51, nr 8 (5.02.2017): 1155–66. http://dx.doi.org/10.1177/0021998317691811.
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The mechanical properties of composite materials are primarily dependent on the load transmission between their components. Especially, the fracture performance of a fibre-reinforced polymer made of a preimpregnated fibres (prepreg) with a three-dimensional z-pin reinforcement can be influenced by the interface characteristics between pins and laminate. X-ray photo-electron spectroscopic (XPS) analysis and scanning electron microscopic (SEM) studies of untreated, cryogenic and plasma surface-treated z-pins were carried out to determine the effect of surface treatments on chemical composition, formation of functional groups and topography of pin surface. Pullout tests were conducted to investigate the impact of a surface treatment on the bridging forces, which have significant influence on delamination toughness of a z-pinned laminate. It was pointed out that a cryogenic treatment cannot lead to an increase of oxygen or nitrogen functional groups at the z-pin surface. Nevertheless, the pullout forces can be increased which are caused by an increased surface roughness. However, with a plasma treatment, an oxygen and nitrogen functionalization can be reached. An increase of the O/C ratio with all plasma treatments can be determined. Summarizing the results, it can be shown that oxygen functional groups can be generated by a plasma treatment. These groups are able to establish covalent bonds between z-pin surface and bulk material, which can lead to a better load transmission between the pins and laminate and thus to higher fracture properties. The increased pullout forces result from a combination of improved adhesion between pins and laminate and increased interlocking effects, due to the higher surface roughness after plasma treatment.
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Kotkowiak, Mateusz, Adam Piasecki, Michał Kotkowiak i Tomasz Buchwald. "The Mechanism of Wear Reduction in the Ni-CaF2 Composite Material: Raman and Confocal Microscopy Insights". Materials 15, nr 16 (10.08.2022): 5501. http://dx.doi.org/10.3390/ma15165501.
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A powder metallurgy process was used to produce high temperature self-lubricating composites based on Ni, with varying content of calcium fluoride (10 wt.% and 20 wt.%). The wear properties of the samples were investigated by a pin-on-disc test at elevated temperature, up to 600 °C. Aside from standard techniques for the sample characterization, confocal microscopy and micro-Raman spectroscopy were used for the first time for this type of sample. These methods were used to examine the changes in topography and to detect the distribution of the tribofilm on sample surfaces. The addition of solid lubricant particles decreased the coefficient of friction and improved the tribological properties, because of the tribofilm which formed on sample surfaces.
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Twardy, S., Otmann Riemer i Ekkard Brinksmeier. "Tribology of Micro Milled Surfaces". Key Engineering Materials 447-448 (wrzesień 2010): 681–84. http://dx.doi.org/10.4028/www.scientific.net/kem.447-448.681.
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Micro milling is an appropriate technology for the flexible production of precise micro molds with complex shapes for metal forming processes (e.g. micro deep drawing). Besides high form accuracy micro ball end milling also provides a specific surface topography which can enhance the tribological behavior during the forming processes. This paper is focusing on the tribological behavior of micro structured surfaces generated by micro milling compared to smooth surfaces. The coefficient of friction was investigated on a pin-on-disc test stand for different materials. The results of the tribological tests suggest a relationship between micro structure and coefficient of friction. Finally, the correlations between machining parameters and tribological behavior will be discussed.
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Furukawa, Yukihiro, Hideo Suzuki, Saburou Shimizu, Naoyuki Ohse, Masahide Watanabe i Kenji Fukuda. "Distribution of Secondary Defects and Electrical Activation after Annealing of Al-Implanted SiC". Materials Science Forum 821-823 (czerwiec 2015): 407–10. http://dx.doi.org/10.4028/www.scientific.net/msf.821-823.407.
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We investigated the relationship between secondary defects and electrical characteristics in the activation annealing (1600 °C-1800 °C) of 4H-SiC after Al implantation (3 × 1017cm-3-3 × 1019cm-3). X-ray topography revealed that the dislocation density did not increase after implantation and annealing. Scanning transmission electron microscopy (STEM) images revealed black spots that aggregate with increase in Al dose. The results of energy dispersive X-ray spectroscopy analysis suggested that these black spots are due to the strain of secondary defects. The I-V characteristics at reverse bias of a pin diode fabricated with Al implantation show that secondary defects shown as black spots in the STEM images do not affect the electrical characteristics under the implantation and annealing conditions used in this experiment.
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Hirsch, Sarah Johanna, Patrick Eiselt, Ismail Ozdemir, Thomas Grund, Andreas Nestler, Thomas Lampke i Andreas Schubert. "Investigation of the Tribological Behaviour of Various AMC Surfaces against Brake Lining Material". Materials 16, nr 3 (21.01.2023): 1001. http://dx.doi.org/10.3390/ma16031001.
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AlSi7Mg/SiCp aluminium matrix composites (AMCs) with a high ceramic content (35 vol.%) that were produced by using the field-assisted sintering technique (FAST) were subjected to tribological preconditioning and evaluated as a potential lightweight material to substitute grey cast iron brake discs. However, since an uncontrolled running-in process of the AMC surface can lead to severe wear and thus to failure of the friction system, AMC surfaces cannot be used directly after finishing and have to be preconditioned. A defined generation of a tribologically conditioned surface (tribosurface) is necessary, as was the aim in this study. To simulate tribological conditions in automotive brake systems, the prepared AMC samples were tested in a pin-on-disc configuration against conventional brake lining material under dry sliding conditions. The influence of the surface topography generated by face turning using different indexable inserts and feeds or an additional plasma electrolytic treatment was investigated at varied test pressures and sliding distances. The results showed that the coefficient of friction remained nearly constant when the set pressure was reached, whereas the initial topography of the samples studied by SEM varied substantially. A novel approach based on analysing the material ratio determined by 3D surface measurement was developed in order to obtain quantitative findings for industrial application.
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Saborowski, Erik, Axel Dittes, Philipp Steinert, Thomas Lindner, Ingolf Scharf, Andreas Schubert i Thomas Lampke. "Effect of Metal Surface Topography on the Interlaminar Shear and Tensile Strength of Aluminum/Polyamide 6 Polymer-Metal-Hybrids". Materials 12, nr 18 (12.09.2019): 2963. http://dx.doi.org/10.3390/ma12182963.
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Mechanical interlocking has been proven to be an effective bonding mechanism for dissimilar material groups like polymers and metals. Therefore, this contribution assesses several surface pretreatments for the metallic adherent. Blasting, etching, combined blasting and etching, thermal spraying, and laser structuring processes are investigated with regard to the achievable interlaminar strength and the corresponding surface roughness parameters. The experiments are carried out on EN AW-6082/polyamide 6 polymer-metal-hybrids, utilizing a novel butt-bonded hollow cylinder specimen geometry for determining the shear and tensile strength. The experimental results indicate that the surface roughness slope has a major impact on the interlaminar strength. A laser-generated pin structure is found to provide the best mechanical performance as well as the highest surface slope of all investigated structuring methods.
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Wang, Yan Qing, Hai Feng Yang, Qing Gong Han, Liang Fang i Shi Rong Ge. "Tribological and Lubrication Properties of Sandblast-Textured Surfaces with Varied Roughness". Advanced Materials Research 154-155 (październik 2010): 1019–22. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.1019.
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Surface roughening, with certain roughness topography, is thought to be as an effective tribological method of decreasing friction coefficient of kinematic pairs. Friction and wear of AISI1045 steel surface roughened by convenient and economical way of sandblasting was investigated under lubrication conditions. Roughened and polished samples run against Φ4mm GCr15 pin lubricated by engine oil were tested in reciprocating mode with different load and speed on UMT- testing machine. It is found that there exists the optima surface roughness (Ra is about 3.92μm) roughened by sandblasting in which the least wettability contact angle between engine oil and textured steel surface is obtained, hence the lowest friction coefficient and wear rate is due to the optima hydrodynamic sliding property, although the sliding surface was not in hydrodynamic lubrication state.
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Bonny, Koenraad, Patrick de Baets, Omer Van der Biest, Jef Vleugels i Bert Lauwers. "Edge Effects in Sliding Wear Behavior of ZrO2-WC Composites and WC-Co Cemented Carbides". Materials Science Forum 561-565 (październik 2007): 503–6. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.503.
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A trend in the development of WC based cemented carbides and zirconia based ceramic composites is grain size refinement and more narrow grain size distributions of the starting powder, in order to accomplish higher hardness and abrasive wear resistance. The current work reports the results of dry sliding wear experiments on laboratory-made electrically conductive ZrO2-WC composites and commercially available WC-Co based cemented carbides, which have been manufactured and finished by rough cutting wire EDM with consecutive execution of gradually finer EDM regimes. Tribological data are obtained using a small-scale pin-on-plate test rig. Wear tracks are analyzed by surface scanning topography and scanning electron microscopy, revealing that the outer extensions of the wear tracks exhibit some differences in wear behavior compared to the central parts.
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Shinde, Dinesh, Mukesh Bulsara i K. N. Mistry. "Tribological performance of non-asbestos brake friction material in contact with brake disc of varying topography". Industrial Lubrication and Tribology 72, nr 10 (4.07.2020): 1277–83. http://dx.doi.org/10.1108/ilt-04-2020-0120.
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Purpose The purpose of this paper is to evaluate experimentally the influence of different surface roughness of the contacting disc on tribological performance of the non-asbestos brake friction material (BFM). Design/methodology/approach Taguchi method was applied to design an experiment using three different discs of gray cast iron with different surface roughness, which is measured using optical profilometer. These discs were subjected to sliding against pins prepared with the developed non-asbestos BFM, using pin on disc friction and wear monitor. Findings The experimental results shows that the disc 2 (Ra = 3.77 µm) gives wear of 22.78 µm and coefficient of friction of 0.462, which is recommended for extreme brake performance. Analysis of Taguchi design revealed that the disc surface was most significant parameter among the parameters under study. Practical implications During braking, continuous sliding between the BFM and brake disc or drum not only results into wear of BFM but also changes the surface finish of the brake drum or disc. This leads to variation in surface topography of the drum or disc surface with application of brakes, which further affects the characteristics of the BFM. Originality/value The tribological performance of BFM depends upon the topography of the surface on which it was sliding. To get best performance of the non-asbestos friction materials, disc having moderate surface finish is recommended. Scanning electron microscope micrographs had shown the different plateaus formed and energy-dispersive X-ray spectroscopy spectra identified presence of different chemical elements prior to sliding of the pins surface over different discs surface topography. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0120/
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Hansen, Erik, Gerda Vaitkunaite, Johannes Schneider, Peter Gumbsch i Bettina Frohnapfel. "Establishment and Calibration of a Digital Twin to Replicate the Friction Behaviour of a Pin-on-Disk Tribometer". Lubricants 11, nr 2 (10.02.2023): 75. http://dx.doi.org/10.3390/lubricants11020075.
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While the modification of surface contacts offers significant potential for friction reduction, obtaining an underlying consistent friction behaviour of real-life experiments and virtual simulations is still an ongoing challenge. In particular, most works in the literature only consider idealised geometries that can be parametrised with simple analytical functions. In contrast to this approach, the current work describes the establishment of a digital twin of a pin-on-disk tribometer whose virtual geometry is completely replicated from real-life post-test topography measurements and fed into a two-scale mixed lubrication solver. Subsequently, several calibration steps are performed to identify the sensitivities of the friction behaviour towards certain geometry features and enable the digital twin to robustly represent the Stribeck curve of the physical experiments. Furthermore, a derivation of the Hersey number is used to generalise the obtained friction behaviour for different dynamic viscosities and allow the validation of the presented method.
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Li, Peng, Jian Li, Yong Zhen Zhang i M. Scherge. "A Simulation of Hydrodynamic Lubrication on Non-Glazed Surfaces under Different Sliding Velocities and Loads". Key Engineering Materials 353-358 (wrzesień 2007): 827–30. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.827.
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Recent researches have found that surfaces with non-glazed or laser dimpling topography offer improved lubricating efficiency and wear resistance under lubrication conditions over their conventional glazed status. It was carried out in this paper to simulate a pin-on-disk experimental condition and perform hydrodynamic lubrication (HL) calculations for both non-glazed and glazed surfaces under conditions of different sliding velocities and loads with a view of understanding the tribological mechanism and characteristics of non-glazed surfaces. The results showed that the minimum film thickness of non-glazed surfaces, which closed to a typical elasto-hydrodynamic lubrication (EHL) film thickness, was thicker than that of glazed surfaces under the condition of low sliding velocities and small loads. At the same time, a decreased maximum pressure of full-film of non-glazed surfaces demonstrated an even pressure distribution on them.
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Kuznetsova, Yulia, Valentin Golosov, Anatoly Tsyplenkov i Nadezhda Ivanova. "Quantifying channel bank erosion of a small mountain river in Russian wet subtropics using erosion pins". Proceedings of the International Association of Hydrological Sciences 381 (1.08.2019): 79–86. http://dx.doi.org/10.5194/piahs-381-79-2019.
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Abstract. Channel bank erosion was monitored using erosion pin arrays in a small mountain stream located in the Tsanyk River basin near the Caucasian Black sea coast. The study area is characterized by high precipitation, low mountainous topography, and flysch bedrock. Erosion pins arrays were installed at six key sections each with different bank lithology and morphology. Bank lithology (bedrock or alluvial deposits), morphology (vertical or concave) and orientation towards the local flow direction were the dominant factors controlling the rate of bank retreat and/or collapse. In contrast to alluvial banks, bedrock slopes are predominantly affected by chemical weathering processes in a wet subtropical climate. Results on sediment mobilization and volume removed are presented for different bank types. Variability in channel bank recessional dynamics is discussed in the context of hydrometeorological data (2016–2018) and an extreme flood.
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Shen, Jui-Hsieh, C. M. Ettles i H. A. Scarton. "The Analysis of Thermoelectric Signals in Metallic Sliding". Journal of Tribology 111, nr 1 (1.01.1989): 114–20. http://dx.doi.org/10.1115/1.3261860.
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The thermoelectric signal from an Alumel pin sliding over a steel surface was recorded and analyzed. The load, speed and surface topography were varied and correlations were attempted of the voltage signal against several parameters. The average temperature of the whole contact was found to agree fairly consistently with the surface temperature rise models of Blok and Archard. Of the available methods of signal analysis, the power spectrum of the voltage signal was found to give the best understanding of the micro-mechanisms of sliding, particularly when compared against the power spectra of profilometer signals. The largest component of the temperature signal was found to be caused by wavelength components equal to the extent of the contact. The correlation distance β* of the test surfaces was much less than the contact extent and contributed negligibly to the voltage signal rise.
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Li, Wenjun, Fusong Yuan, Jing Bai, Junyao Cheng, Hongxiang Li, Jianqiao Zheng, Wei Bai i Peijun Lyu. "In vivo evaluation of bending strengths and degradation rates of different magnesium pin designs for oral stapler". Journal of Applied Biomaterials & Functional Materials 18 (styczeń 2020): 228080001983640. http://dx.doi.org/10.1177/2280800019836400.
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Magnesium alloys have been potential biodegradable implants in the areas of bone, cardiovascular system, gastrointestinal tract, and so on. The purpose of this study is to evaluate Mg–2Zn alloy degradation as a potential suture material. The study included Sprague–Dawley (SD) rats in vivo. In 24 male SD rats, tests in the leg muscle were conducted using traditional surgical incision and insertion of magnesium alloys of different designs into the tissue. The material degradation topography, elemental composition, and strength of the pins were analyzed. This paper explores magnesium pins with different cross-sectional shapes and diameters to establish a suitable pin diameter and shape for use as an oral stapler, which must have a good balance of degradation rate and strength. The results showed there were good bending strengths over different degradation periods in groups with diameters of 0.8 mm and 0.5 mm, and no significantly different bending strength between the groups of triangle and round cross-section shapes with same diameter of 0.3 mm, although the degradation rate still needs to be improved.
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Maculotti, Giacomo, Edoardo Goti, Gianfranco Genta, Luigi Mazza i Maurizio Galetto. "Uncertainty-based comparison of conventional and surface topography-based methods for wear volume evaluation in pin-on-disc tribological test". Tribology International 165 (styczeń 2022): 107260. http://dx.doi.org/10.1016/j.triboint.2021.107260.
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Shi, Ruimin, Bukang Wang, Jiquan Liu, Zhiwei Yan i Lei Dong. "Influence of Cross-Shear and Contact Pressure on Wear Mechanisms of PEEK and CFR-PEEK in Total Hip Joint Replacements". Lubricants 10, nr 5 (30.04.2022): 78. http://dx.doi.org/10.3390/lubricants10050078.
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With the increasing market demand for artificial hip joints, total hip joint replacement has gradually become an effective means of treating a series of hip joint diseases. In order to improve the service life of artificial hip joints, some new artificial hip joint materials, including polyetheretherketone (PEEK) and carbon fiber reinforced polyetheretherketone (CFR-PEEK), have been developed. In this paper, pin-on-plate wear tests under different cross-shear ratios and contact pressures were carried out to study the wear mechanism and worn surface topography of PEEK and CFR-PEEK. The experimental results showed that the wear of PEEK was associated with cross-shear, while CFR-PEEK was not. When the cross-shear ratio was 0.039 and contact pressure was 3.18 MPa, PEEK had poor wear resistance and its wear factor was about eight times that of ultra-high molecular weight polyethylene (UHMWPE). The wear resistance of CFR-PEEK had a significant advantage, since its wear factor was about 30% of that of PEEK. The wear factors of PEEK and CFR-PEEK increased as the contact pressure increased. The arithmetic average of the height amplitude of the surface, Sa, also increased gradually according to the topography of the worn surface. The wear mechanisms of PEEK and CFR-PEEK were scratching, plough cutting, and abrasion Since CFR-PEEK had good wear resistance and insensitivity to cross-shear motion, it is suitable for making artificial hip joints under low contact pressure condition.
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Prajapati, Deepak K., i Mayank Tiwari. "The correlation between friction coefficient and areal topography parameters for AISI 304 steel sliding against AISI 52100 steel". Friction 9, nr 1 (29.07.2020): 41–60. http://dx.doi.org/10.1007/s40544-019-0323-1.
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Abstract Dry wear experiments provide an insight detail on how severely contacting surfaces change under unlubricated sliding condition. The theory of dry sliding wear is used for understanding mixed-lubrication regime in which asperity interactions play a significant role in controlling of the friction coefficient (f). The purpose of this work is to study the tribological behavior of AISI 304 steel in contact with AISI 52100 steel during wear. Both materials are used in rolling element bearings commanly. Experiments are carried out using a pin-on-disc tribometer under dry friction condition. The areal (three dimensional, 3D) topography parameters are measured using a 3D white light interferometer (WLI) with a 10× objective. After wear tests, wear mechanisms are analyzed utilizing scanning electron microscope (SEM). Factorial design with custom response surface design (C-RSD) is used to study the mutual effect of load and speed on response variables such as f and topography parameters. It is observed that the root mean square roughness (Sq) decreases with an increase in sliding time. Within the range of sliding time, Sq decreases with an increase in the normal load. Within the range of sliding speed and normal load, it is found that Sq, mean summit curvature (Ssc), and root mean square slope (Sdq) are positively correlated with f. Whereas, negative correlation is found between f and correlation length (Sal), mean summit radius (R), and core roughness depth (Sk).
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Perez Delgado, Yeczain, Koen Bonny, Patrick De Baets, Patric Daniel Neis, Vanessa Rodriguez Fereira, O. Malek, J. Vleugels i B. Lauwers. "Dry sliding friction and wear response of WC-Co hardmetal pairs in linearly reciprocating and rotating contact". International Journal Sustainable Construction & Design 2, nr 1 (6.11.2011): 12–18. http://dx.doi.org/10.21825/scad.v2i1.20430.
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This paper presents an experimental evaluation of friction and wear properties of WC-Cocemented carbides. A comparison is made between unlubricated rotating and linearly reciprocating pin-onplate sliding pairs. The plate specimens were WC-10wt%Co grades surface finished by polishing orsequential wire-EDM steps, whereas WC-6wt%Co pins were used as counter body. The tests were carriedout at room temperature using a sliding speed of 0.30m/s and mean Hertzain contact pressures of 1.76 and2.08 GPa, i.e., normal contact loads of 15N and 25N, respectively. The worn surfaces on plate sampleswere quantified in terms of 2–D wear profiles obtained by means of surface topography scanningequipment. Wear mechanisms such as polishing and abrasion were identified using optical microscopy.Inferior tribological characteristics for wire-EDM surface finish compared to polishing were found. Higherfriction coefficient and wear levels were measured in unidirectional rotating sliding experiments comparedto linearly reciprocating test conditions.
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Goldsztajn, Karolina, Julia Lisoń-Kubica, Joanna Jaworska, Katarzyna Jelonek, Wojciech Kajzer i Janusz Szewczenko. "MECHANICAL PROPERTIES OF POLYMER COATINGSCONTAINING HAP AND ACTIVE SUBSTANCE ON A METALSUBSTRATEWASNOCI". Tribologia 304, nr 2 (30.06.2023): 17–25. http://dx.doi.org/10.5604/01.3001.0053.6120.
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Titanium alloys are currently widely used in implantation, especially in orthopaedics. However, undesirablereactions caused by aluminium and vanadium ions released from the surface of the most commonly used alloys,Ti6Al4V and Ti6Al7Nb, result in the need to modify the surface of the material to improve biocompatibility.Among the available modification methods, one can mention the application of biodegradable polymercoatings, which, apart from improving biocompatibility by limiting the penetration of alloying element ionsinto the tissue environment, can also be a matrix for the release of mineral (HAp) and active substances. Thepaper attempts to determine the mechanical properties of PLGA polymer coatings containing nanoparticlehydroxyapatite and an active substance (dexamethasone) applied with the ultrasonic spray coating methodon a Ti6Al7Nb alloy substrate. The scope of the research included: surface topography testing using an opticalprofilometer, coating adhesion testing to the substrate using the scratch test method and tribological testing(Pin-On-Disc method).
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Whitley, James, Mieke Prent i Stuart Thorne. "Praisos IV: a preliminary report on the 1993 and 1994 survey seasons". Annual of the British School at Athens 94 (listopad 1999): 215–64. http://dx.doi.org/10.1017/s0068245400000587.
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Two seasons of fieldwalking were undertaken in the environs of the city of Praisos in Eastern Crete in 1993 and 1994. This is a preliminary report on the results. The topography of the area is described, as are the survey methods used. Finds include sites of FN/EM I date; MM ‘megalithic’ structures and one possible sanctuary; few remains of Neopalatial date. Attention is concentrated on the LM III, PG, G and Orientalising periods which saw a movement of settlement from the refuge settlement of Kypia above Kalamafki to Praisos itself. The urban survey of 1994 indicates that Praisos was a considerable settlement well before the Classical period, and there seems to be some overlap in the periods in which Kypia and Praisos were occupied. Further work was also undertaken on the Classical and Hellenistic periods in the Praisos area. Later periods have proven more difficult to pin down through analysis of their surface remains.
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Nabhan, Ahmed, Galal Sherif, Ragab Abouzeid i Mohamed Taha. "Mechanical and Tribological Performance of HDPE Matrix Reinforced by Hybrid Gr/TiO2 NPs for Hip Joint Replacement". Journal of Functional Biomaterials 14, nr 3 (2.03.2023): 140. http://dx.doi.org/10.3390/jfb14030140.
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Hip joint collapse is a very common health problem. Many cases need a joint replacement, so nano-polymeric composites are an ideal alternative solution. Due to its mechanical properties and wear resistance, HDPE might be considered a suitable alternative to frictional materials. The current research focuses on using hybrid nanofiller TiO2 NPs and nano-graphene with various loading compositions to evaluate the best loading amount. The compressive strength, modules of elasticity, and hardness were examined via experiments. The COF and wear resistance were evaluated via a pin-on-disk tribometer. The worn surfaces were analyzed based on 3D topography and SEM images. The HDPE samples with various compositions of 0.5%, 1.0%, 1.5%, and 2.0 wt.% filling content of TiO2 NPs and Gr (with a ratio of 1:1) were analyzed. Results revealed that hybrid nanofiller with a composition of 1.5 wt.% exhibits superior mechanical properties compared to other filling compositions. Moreover, the COF and wear rate decreased by 27.5% and 36.3%, respectively.
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Li, Chang He, Guang Qi Cai i Shi Chao Xiu. "Study on Surface Topography and Tribological Characteristics Finished by Abrasive Jet with Grinding Wheel as Restraint". Materials Science Forum 532-533 (grudzień 2006): 61–64. http://dx.doi.org/10.4028/www.scientific.net/msf.532-533.61.
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The abrasive jet finishing process with wheel as restraint is a kind of compound precision finishing process that combined grinding with abrasive jet machining, in which inject slurry of abrasive and liquid solvent to grinding zone between grinding wheel and work surface under no radial feed condition when workpiece grinding were accomplished. The abrasive particles are driven and energized by the rotating grinding wheel and liquid hydrodynamic pressure and increased slurry speed between grinding wheel and work surface to achieve micro removal machining. The micro removal machining with grinding wheel as restraint, not only to attain higher surface form accuracy but also to can acquire efficiently defect-free finishing surface with Ra0.15～ 1.6μm and finally achieve high efficiency, high precision and low roughness values, furthermore, integrating grinding process and abrasive jet process into one features. In the paper, surface topography and tribological characteristics finished by abrasive jet with grinding wheel as restraint were analyzed. Experiments were performed with plane grinder M7120 and workpiece material Q235A. The machined surface morphology was studied using SEM and the microscope and microcosmic geometry parameters were measured with TALSURF5 instrument. The experimental results show that microcosmic geometry parameter values were diminished comparing with ground surface. The tribological characteristics of finished surface were also investigated with pin on disk wear tester of MG-2000. The experimental results show that the friction coefficient and wear amounts of finishing machining surface were obviously decreased comparing with ground surface. As a result, life and precision consistency of finished workpiece were improved.
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Charbonneau, Bianca R., i Stephanie M. Dohner. "Microscale and Mesoscale Aeolian Processes of Sandy Coastal Foredunes from Background to Extreme Conditions". Remote Sensing 13, nr 21 (8.11.2021): 4488. http://dx.doi.org/10.3390/rs13214488.
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Aeolian transport affects beach and foredune pre-storm morphologies, which directly contribute to storm responses. However, significant spatiotemporal variation exists within beach-dune systems regarding how biotic and abiotic factors affect topography. There are multiple metrics for quantifying topographic change, with varying pros and cons, but understanding how a system changes across spatiotemporal scales relative to varying forcings is necessary to accurately model and more effectively manage these systems. Beach and foredune micro- and mesoscale elevation changes (Δz) were quantified remotely and in situ across a mid-Atlantic coastal system. The microscale field collections consisted of 27 repeat measurements of 73 elevation pins located in vegetated, transitional, and unvegetated foredune microhabitats over three years (2015 to 2018) during seasonal, event-based, and background wind-condition collections. Unoccupied aerial System (UAS) surveys were collected to link microscale point Δz to mesoscale topographic change. Microscale measurements highlight how Δz varies more pre- to post-event than seasonally or monthly, but regardless of collection type (i.e., seasonal, monthly, or event-based), there was lower Δz in the vegetated areas than in the associated unvegetated and partially vegetated microhabitats. Despite lower Δz values per pin measurement, over the study duration, vegetated pins had a net elevation increase of ≈20 cm, whereas transitional and unvegetated microhabitats had much lower change, near-zero net gain. These results support vegetated microhabitats being more stable and having better sediment retention than unvegetated and transitional areas. Comparatively, mesoscale UAS surfaces typically overestimated Δz, such that variation stemming from vegetation across microhabitats was obscured. However, these data highlight larger mesoscale habitat impacts that cannot be determined from point measurements regarding volumetric change and feature mapping. Changes in features, such as beach access paths, that are associated with increased dynamism are quantifiable using mesoscale remote sensing methods rather than microscale methods. Regardless of the metric, maintaining baseline data is critical for assessing what is captured and missed across spatiotemporal scales and is necessary for understanding the contributors to heterogeneous topographic change in sandy coastal foredunes.
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Chen, Zeyu, Yafei Liu, Hongyu Peng, Qianyu Cheng, Shanshan Hu, Balaji Raghothamachar, Michael Dudley, Reza Ghandi, Stacey Kennerly i Peter Thieberger. "Effect of Annealing Conditions on Recovery of Lattice Damage in a High-Energy-Implanted 4H-SiC Superjunction PIN Diode". ECS Journal of Solid State Science and Technology 11, nr 6 (1.06.2022): 065003. http://dx.doi.org/10.1149/2162-8777/ac7351.
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A high energy ion implantation system has been recently developed at the Tandem Van de Graaff facility at Brookhaven National Laboratory with tunable energy to 150 MeV capable of multi-step, deep implantation in 4H-SiC wafers with dopant atoms, such as B, P, Al, and N. Medium and high voltage devices with deep junctions can be fabricated using this system. Lattice strain introduced by the implantation process needs to be recovered and dopant atoms activated by appropriate annealing process as the device performance is strongly associated with the extent of recovery of the lattice. Using Synchrotron X-ray Rocking Curve Topography (SXRCT) and Reciprocal Space Mapping (RSM), the strain induced by high energy implantation of Al and N in 4H-SiC in different patterns are measured and mapped. It is observed that the strain levels correlate with the total fluence levels. PiN diodes fabricated on these implanted wafers were then annealed at temperatures ranging from 1700 °C to 2000 °C for 60 min. The SXRCT and RSM analysis of the annealed samples suggests that for the same annealing duration, higher temperature leads to better lattice recovery.
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Chen, Zeyu, Yafei Liu, Hongyu Peng, Qianyu Cheng, Shanshan Hu, Balaji Raghothamachar, Michael Dudley, Reza Ghandi, Stacey Kennerly i Peter Thieberger. "Effect of Annealing Conditions on Recovery of Lattice Damage in a High-Energy-Implanted 4H-SiC Superjunction PIN Diode". ECS Journal of Solid State Science and Technology 11, nr 6 (1.06.2022): 065003. http://dx.doi.org/10.1149/2162-8777/ac7351.
Pełny tekst źródłaStreszczenie:
A high energy ion implantation system has been recently developed at the Tandem Van de Graaff facility at Brookhaven National Laboratory with tunable energy to 150 MeV capable of multi-step, deep implantation in 4H-SiC wafers with dopant atoms, such as B, P, Al, and N. Medium and high voltage devices with deep junctions can be fabricated using this system. Lattice strain introduced by the implantation process needs to be recovered and dopant atoms activated by appropriate annealing process as the device performance is strongly associated with the extent of recovery of the lattice. Using Synchrotron X-ray Rocking Curve Topography (SXRCT) and Reciprocal Space Mapping (RSM), the strain induced by high energy implantation of Al and N in 4H-SiC in different patterns are measured and mapped. It is observed that the strain levels correlate with the total fluence levels. PiN diodes fabricated on these implanted wafers were then annealed at temperatures ranging from 1700 °C to 2000 °C for 60 min. The SXRCT and RSM analysis of the annealed samples suggests that for the same annealing duration, higher temperature leads to better lattice recovery.
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Vidal Vázquez, E., J. G. V. Miranda i J. Paz-Ferreiro. "A multifractal approach to characterize cumulative rainfall and tillage effects on soil surface micro-topography and to predict depression storage". Biogeosciences 7, nr 10 (1.10.2010): 2989–3004. http://dx.doi.org/10.5194/bg-7-2989-2010.
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Abstract. Most of the indices currently employed for assessing soil surface micro-topography, such as random roughness (RR), are merely descriptors of its vertical component. Recently, multifractal analysis provided a new insight for describing the spatial configuration of soil surface roughness. The main objective of this study was to test the ability of multifractal parameters to assess in field conditions the decay of initial surface roughness induced by natural rainfall under different soil tillage systems. In addition, we evaluated the potential of the joint use of multifractal indices plus RR to improve predictions of water storage in depressions of the soil surface (MDS). Field experiments were performed on an Oxisol at Campinas, São Paulo State (Brazil). Six tillage treatments, namely, disc harrow, disc plough, chisel plough, disc harrow + disc level, disc plough + disc level and chisel plough + disc level were tested. In each treatment soil surface micro-topography was measured four times, with increasing amounts of natural rainfall, using a pin meter. The sampling scheme was a square grid with 25 × 25 mm point spacing and the plot size was 1350 × 1350 mm (≈1.8 m2), so that each data set consisted of 3025 individual elevation points. Duplicated measurements were taken per treatment and date, yielding a total of 48 experimental data sets. MDS was estimated from grid elevation data with a depression-filling algorithm. Multifractal analysis was performed for experimental data sets as well as for oriented and random surface conditions obtained from the former by removing slope and slope plus tillage marks, respectively. All the investigated microplots exhibited multifractal behaviour, irrespective of surface condition, but the degree of multifractality showed wide differences between them. Multifractal parameters provided valuable information for characterizing the spatial features of soil micro-topography as they were able to discriminate data sets with similar values for the vertical component of roughness. Conversely, both, rough and smooth soil surfaces, with high and low roughness values, respectively, can display similar levels of spectral complexity. Although in most of the studied cases trend removal produces increasing homogeneity in the spatial configuration of height readings, spectral complexity of individual data sets may increase or decrease, when slope or slope plus tillage tool marks are filtered. Increased cumulative rainfall had significant effects on various parameters from the generalized dimension, Dq, and singularity spectrum, f(α). Overall, micro-topography decay by rainfall was reflected on a shift of the singularity spectra, f(α) from the left side (q>>0) to the right side (q>0) to the left side (q
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Sieber, René, Remo Eichenberger i Lorenz Hurni. "3D Carto-Graphics – Principles, Methods and Examples for Interactive Atlases". Abstracts of the ICA 1 (15.07.2019): 1. http://dx.doi.org/10.5194/ica-abs-1-338-2019.
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<p><strong>Abstract.</strong> Atlases are designed to visualize, explore and analyze topographic and thematic information in a geographic environment. As 3D data and real-time display techniques are increasingly available, a trend towards 3D atlases can be observed like the newly released Earth 3D Amazing Atlas (2017) and the Atlas of Switzerland &ndash; online (2016). While creating such interactive 3D atlases, editors are often confronted with the question: How realistic should a cartographic 3D representation look like? Can we introduce some visualization guidelines or even rules to determine the „graphic style“ of cartographic 3D elements? 3D visualizations tend to let users ask for more and more details, leading to photorealistic representations. But photorealism is mostly not suited to pin point the characteristics of a theme; obviously, a creek or a trail would hardly be recognized in a forest area. As Goralski (2009, p.3) states: “3D maps are not meant to be realistic 3D representations of the real world. As in other map types, cartographic rules of abstraction, symbolization and generalization have to be used, to assure efficient transfer of the depicted geographical information, tailored to the purpose, and suitable for the target map user.”</p><p>In our presentation, we will clarify the term of 3D carto-graphics, depict principles, and describe suitable methods and corresponding techniques. In the context of the national Atlas of Switzerland, we will apply and examine these design concepts for 3D representations within the 3D mapping space (Sieber et al. 2013).</p><p>A carto-graphic style for 3D is based on 2D cartographic rules (Imhof 1965) and non-photorealistic computer graphics (Doellner 2012, Bodum 2005). Principles concerning 3D modeling are fundamental for the different representational aspects. In this context, we will discuss principles such as a degree of realism, the level of visual complexity of 3D maps, the graphic quality of map elements, the 3D visualization and symbolization (Near-Far/Distance-Density problem), etc. considering dynamic and real-time applications. As an example of a 3D principle, the <i>visualization</i> should always originate from 3D data; thus a 2D map is a special case of a 3D map (Sieber et al. 2012).</p><p><i>Methods and techniques</i> of 3D modeling affect the whole 3D scene consisting of terrain/topography, and different map objects. We will present some ideas and techniques how to treat 3D topography, and objects like point symbols, charts, lines, areas and solid objects considering real-time interaction. As an example of such methods recommended in the field of 3D topography, DTMs should be based on high-resolution and smoothed TINs applying techniques of low poly height fields (Ferguson 2013). Adaptive DTM smoothing using topographic position index (TPI) and filtering techniques are also taken into consideration (Guisan et al. 1999, Kettunen et al. 2017). For appropriate relief shading, an exemplary approach using smoothing and enhance techniques is suggested (Geisthövel 2017).</p><p>To illustrate the described methods and techniques, we present and discuss characteristic examples from various application fields. Examples may come from cartography, computer graphics, and even from data journalism and info-graphics. In order to demonstrate the feasibility and the usability of this approach, we plan to implement a set of 3D visualizations, which can be interacted with in real-time by means of the Virtual Globe engine of the Atlas of Switzerland &ndash; online.</p>
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Schirdewahn, Stephan, Felix Spranger, Kai Hilgenberg i Marion Merklein. "Laser Implantation of Niobium and Titanium-Based Particles on Hot Working Tool Surfaces for Improving the Tribological Performance within Hot Stamping". Defect and Diffusion Forum 404 (październik 2020): 117–23. http://dx.doi.org/10.4028/www.scientific.net/ddf.404.117.
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Within the scope of this work, a new approach named laser implantation process has been investigated, in order to improve the tribological performance of hot stamping tools. This surface engineering technology enables the generation of dome-shaped, elevated and highly wear resistant microfeatures on tool surfaces in consequence of a localized dispersing of hard ceramic particles via pulsed laser radiation. As a result, the topography and material properties of the tool and thus the tribological interactions at the blank-die interface are locally influenced. However, a suitable selection of hard ceramic particles is imperative for generating defect-free surface features with a high share of homogenously disturbed particles. For this purpose, different niobium (NbB2 and NbC) as well as titanium-based (TiB2 and TiC) materials were embedded on hot working tool specimens and subsequently analyzed with regard to their resulting shape and mechanical properties. Afterwards, modified pin-on-disk tests were carried out by using conventional and laser-implanted tool surfaces, in order to evaluate the wear and friction behavior of both tooling systems.
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Lenz, Bastian, Stefanie Hoja, Michaela Sommer, Henning Hasselbruch, Andreas Mehner i Matthias Steinbacher. "Potential of Nitrided and PVD-MoS2:Ti-Coated Duplex System for Dry-Running Friction Contacts". Lubricants 10, nr 10 (20.09.2022): 229. http://dx.doi.org/10.3390/lubricants10100229.
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Self-lubricating coatings can be used to increase the service life of machine parts which are subjected to high mechanical loads. The present work is concerned with the combination of nitriding and a subsequent Ti-doped MoS2 coating. The focus of the investigations is on the impact of the compound layer on the wear behavior of the coating since the changes in the surface topography due to compound layer growth and pore formation inside the compound layers are expected to have an impact of the adhesion strength and the wear behavior. For this purpose, compound layers with varying thickness and porosity were formed in the surface area of the material EN31CrMoV9 by gas nitriding. A MoS2:Ti PVD monolayer was applied directly on the compound layers. The wear behavior was evaluated using the pin-on-disc test. The MoS2:Ti solid lubricant coatings show good adhesion on the compound layers without any interlayer. Compared with the nitrided reference state, the coating significantly improved the wear behavior of the surface treated material.
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Madej, Monika. "Tribological Properties of Diamond-Like Carbon Coatings". Advanced Materials Research 874 (styczeń 2014): 9–15. http://dx.doi.org/10.4028/www.scientific.net/amr.874.9.
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The aim of the study was to analyze the superhard anti-wear diamond-like carbon coatings produced by Plasma Assisted Chemical Vapor Deposition (PACVD) and Physical Vapour Deposition (PVD). The a-C:H and a-C:H:W coatings were deposited on steel elements operating under friction conditions. The analysis involved comparing the tribological properties of coated metal elements with those of uncoated elements. It was essential to analyze how the coating composition and structure influence the tribological behaviour of elements under dry and lubrication friction conditions. The coating structure was analyzed by observing the topography of the surface and the cross-sections using an atomic force microscope (AFM) and a scanning electron microscope (SEM). The results were employed to determine the elemental composition and thickness of the coatings. The tribological tests were performed applying a ball-on-disc tribometer and using a pin-on-plate tribometer. The tribological properties were analyzed also in a micro scale using a microtribometer. Compared with the substrate material - steel, the diamond-like carbon coatings showed lower linear wear, lower friction coefficient and higher hardness.
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WOŚ, Sławomir, Waldemar KOSZELA i Paweł PAWLUS. "THE EFFECT OF OIL POCKET ARRAYS ON FRICTION COEFFICIENT". Tribologia, nr 4 (31.08.2017): 97–105. http://dx.doi.org/10.5604/01.3001.0010.6037.
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Experiments were carried out using pin-on-disc tester in conformal lubricated contact conditions for different normal loads. Surface texturing was done using abrasive jet machining with the application of laser cut mask. In order to eliminate the effect of different input variables in all the experiments, pit-area ratio and sizes of oil pockets were very similar. Five types of oil pocket arrays were tested: radial, concentric, spiral, of a square arrangement, and of a random arrangement for 5% and 17% of pit-area ratio. Different dimple diameters caused various oil pocket densities. The experiments were also made for untextured polished discs. During tests, the friction force was monitored as a function of time. Before and after tests, disc surface topography was measured using a white light interferometer Talysurf CCI Lite. The beneficial effect of surface texturing was obtained for spiral arrays of dimples on disc surface. The presence of a radial array of oil pockets resulted in the worst tribological properties of tribological assemblies containing textured discs.
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Wierzbicka, Natalia, Rafał Talar, Karol Grochalski, Adam Piasecki, Wiesław Graboń, Miłosz Węgorzewski i Adam Reiter. "Influence of Inorganic Additives on the Surface Characteristics, Hardness, Friction and Wear Behavior of Polyethylene Matrix Composites". Materials 16, nr 14 (12.07.2023): 4960. http://dx.doi.org/10.3390/ma16144960.
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The aim of this research was to analyze the effect of inorganic additives on the tribological properties of the high-density polyethylene (HDPE) matrix composite surface. Titanium (Ti) and hexagonal boron nitride (hBN) were added in different mass fractions. The samples were produced by pressing a pre-prepared mixture of granules. The composite samples with the following mass fractions of additives were fabricated: 5% hBN, 10% hBN, 28% Ti–2% hBN, 23% Ti–7% hBN, and 20% Ti–10% hBN. An even distribution of individual additives’ concentrations was confirmed. Observations of morphology, surface topography, hardness, and tribological measurements were conducted using reciprocating motion tests with the “pin-on-flat” and rotational tests with the “pin-on-disc” configuration. Subsequently, microscopic observations and measurements of the wear track profile were carried out. Additionally, geometry parameters of the contacting elastic body were calculated for various counter-samples. It was found that the Shore D hardness of samples containing Ti and hBN increased with the Ti content, while the coefficient of friction (COF) value decreased. The addition of hBN alone did not significantly affect the hardness, regardless of the ratio, while the COF increased with the increasing hBN content. The COF value doubled with the addition of 10% hBN (COF = 0.22), whereas the addition of 90% Ti–10% hBN resulted in a decrease in the COF value, to COF = 0.83. The highest hardness value was obtained for the sample containing 28% Ti–2% hBN (66.5), while the lowest was for the sample containing 10% hBN (63.2). The wear track analysis, including its height and width caused by deformation, was detected using a focal differentiation microscope and scanning electron microscopy. Additionally, EDS maps were generated to determine the wear characteristics of the composite.
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Le, Vu Nguyen Anh, i Jau Wen Lin. "Influence of Aluminum Nanoparticles Additives on Tribological Properties of Base Oil". Key Engineering Materials 737 (czerwiec 2017): 184–91. http://dx.doi.org/10.4028/www.scientific.net/kem.737.184.
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This study investigates the influence of aluminum nanoparticles, oleic acid as dispersants, and rotational speed on the tribological behavior of a lubricant. The experiments are performed on a pin-on-disc tribotester at a normal force of 90 N and a rotational speed ranging from 150 rpm to 600 rpm. Both the aluminum nanoparticles and oleic acid are in concentrations from 0 to 1 wt% and are added to the SN150 base oil. The results revealed that the addition of aluminum nanoparticles and oleic acid to the base oil will lead to significant friction reduction and anti-wear properties. The coefficient of friction (COF) and wear rate decreased after an increase in the concentration of nanoparticles and oleic acid, and an optimum concentration level was exhibited in which both COF and wear-rate were lowest. The viscosity and temperature of the lubricant are also evaluated. Further, the topography of discs after performance of sliding test have been analyzed through the use of an optical microscope, a scanning electron microscope (SEM), and an energy dispersive spectrometer (EDS) in order to interpret the mechanisms of nanoparticle action used to prevent friction and subsequent wear.
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Kusmoko, Alain, i Hui Jun Li. "Surface Morphology and Wear Analysis of Stellite 6 Deposited on 9Cr-1Mo Steel Substrate by Laser Cladding". Advanced Materials Research 1119 (lipiec 2015): 640–44. http://dx.doi.org/10.4028/www.scientific.net/amr.1119.640.
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Stellite 6 was deposited by laser cladding on a 9Cr-1Mo (P91) substrate with energy inputs of 1 kW (P91-1) and 1.8 kW (P91-1.8). The chemical compositions, microstructures and surface roughnesses of these coatings were characterized by atomic absorption spectroscopy, optical microscopy, scanning electron microscopy and atomic force microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was evaluated using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the 9Cr-1Mo (P91) steel substrate with the lower heat input (P91-1). Further, the Stellite coating for P91-1 was significantly harder than that obtained for P91-1.8. The wear test results indicated that the weight loss for P91-1 was much lower than for P91-1.8. The surface topography data indicated that the surface roughness for P91-1 was much lower than for P91-1.8. It is concluded that the lower hardness of the coating for P91-1.8, together with the softer underlying substrate structure, markedly reduced the wear resistance of the Stellite 6 coating.
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Deng, Chaoyong, Jian Yin, Hongbo Zhang, Xiang Xiong, Pei Wang, Miao Sun i Xiaoguang Wu. "Dynamic variation of arc discharge and its effect on corrosion direction under current-carrying sliding". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 233, nr 3 (4.06.2018): 380–92. http://dx.doi.org/10.1177/1350650118781143.
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Current-carrying sliding tests were performed on an HST-100 high-speed multifunction friction and wear tester. Cf/Cu/C composite was used as the pin, and commercial QCr0.5 was employed as the disk. Sliding tests were carried out at a speed of 30 m/s and a load of 70 N under 25 A, 50 A, 75 A, and 100 A, respectively. Light intensity was collected by a photodiode, and the arc discharge process was recorded by a high-speed camera (HX-5) with a capture rate of 20,000 fp/s. The worn surfaces were characterized by a Nova NanoSEM230 scanning electron microscope and a NANO Focus AG three-dimensional topography instrument. The result indicates that arc discharge occurs randomly, both temporally and spatially, as long as the condition is suitable and occurs more at the beginning and end of the friction process. The arc moves constantly along the friction direction to the outlet. Compared to the inlet, the erosion of the outlet is considerably worse. This finding indicates the arc is moving towards the outlet and grows by a large margin when it leaves the friction surface at the outlet end.