Abrasion Testing Machine Research Articles

Dry sand abrasion characteristics of WC-10Ni+NiCrBSi coatings

A WC-10Ni/NiCrBSi coating was prepared and applied to the surface of Q235 steel through vacuum brazing. Using a self-developed dry sand abrasion test machine, the effects of the abrasive sand’s type, load, and sliding speed on the dry sand abrasion property of the coating were analysed. The wear mechanism of dry sand abrasion was also investigated. The results indicated that the coating cross-section comprised three layers: the substrate, the interface layer, and the surface layer. The hard layer served as the main distribution area of WC hard particles, which directly determined the hardness and wear resistance of the coating. WC particles, fortified by a γ-Ni solid solution, enhanced the wear resistance and hardness of the coating. In the friction and wear test, when ceramic abrasives were employed, the coating sample exhibited a loss of only 23 mg, constituting only 7.9% of that observed with quartz sand abrasives. Under low loading conditions, the wear mass loss exhibited a linear relationship with the applied load. During these low-load scenarios, the abrasive particles operated through a rolling motion, thereby entailing an abrasive wear mechanism. Conversely, when the load exceeded 0.05 MPa, the primary mode of abrasive particle motion transitioned into sliding with burial, resulting in a combination of fatigue wear and abrasive wear mechanisms. Therefore, the dry sand abrasion mechanism inherent to composite coatings can be attributed to the protective shielding role played by WC particles on the substrate. This shielding function effectively mitigates and counteracts the abrasive cutting effects induced by abrasive particles.

A Study of the Three-Body Abrasive Wear Resistance of 5V/5Nb-5Cr-5Mo-5W-5Co-Fe Multicomponent Cast Alloys with Different Carbon Percentages.

Since it is well known in the literature that transition metals can form extremely hard carbides and effectively strengthen a material's matrix, recently, some of them, such as V, Nb, Cr, Mo, and W, have been simultaneously added to cast iron. In addition, it is common to add Co to cast iron to strengthen the material's matrix. However, the wear resistance of cast iron can also be considerably affected by the addition of C, which is rarely discussed in the literature by the experts. Therefore, the effect of C content (1.0; 1.5; 2.0 wt.%) on the abrasive wear behavior of 5 wt.% V/Nb, Cr, Mo, W, and Co alloys was investigated in this study. An evaluation was conducted using a rubber wheel abrasion testing machine in accordance with ASTM G65 with silica sand (1100 HV; 300 μm) as abrasive particles. The results show that plural carbides (MC, M2C, and M7C3) precipitated on the microstructure of the material, which is not unlike the behavior of other types of carbides as the quantity of C increases. The hardness and wear resistance properties of 5V-5Cr-5Mo-5W-5Co-Fe and 5Nb-5Cr-5Mo-5W-5Co-Fe multicomponent cast alloys increased as the quantity of C increased. However, we observed no significant difference in the hardness between the two materials with the same C additions, while 5Nb presented better wear resistance properties compared to the 5V sample due to the larger size of NbC compared to VC. Therefore, it can be determined that, in this study, the size of the carbide plays a more important role than its volume fraction and hardness.

Wear Characteristics of Hybrid Polymer Composite Manufactured by Hand Layup Technique Using Fuzzy Logic Systems

Synthetic fiber reinforced composites have already been proved to be stronger and more durable. The composites are being globally used in all the possible fields like automobiles, aircraft and marine industry. The present work is an investigation on the wear behaviour of the hybrid polymer composites. In this experimental work, the carbon fibres are reinforced with vinyl ester, g-C3N4 and Si3N4 were used to obtain hybrid composite by hand layup technique. The experiments were designed according to Taguchi (L27) orthogonal array. Experiments are carried out using slurry abrasive wear testing machine to inspect the wear rate. Further, a fuzzy logic model is adopted for the estimation of sliding wear in hybrid composites by the experimental data. Results showed that estimated fuzzy logic outputs are compared to experimental results, which is very much satisfied with a mean error estimation of 0.27%, so that the fuzzy logic model can be efficiently used to compute the wear performance.

Wear resistance performance of high entropy alloy–ceramic coating composites synthesized via a novel combined process

Titanium nitride (TiN), characterized by its high hardness and strength, was widely used as ceramic coating to improve the wear resistance of matrix materials. In this work, AlCrFeNiTix high-entropy alloy (HEA) powders were synthesized by direct electrochemical reduction in molten salt from the mixed metal oxides. Then, TiN ceramic coating on the AlCrFeNiTix bulk HEA containing the topologically close-packed (TCP) phase (σ phase, Laves phase, and Ti3Al phase) was prepared by vacuum hot pressing sintering, where nitride element come from boron nitride parting agent sprayed on the graphite mold. The effect of titanium content on the crystal structure, microstructure, hardness, and wear resistance of the products were investigated by X-ray diffraction, field emission scanning electron microscope, field emission electron-probe microanalysis, Vickers hardness tester, and friction–abrasion testing machine. The bulk HEAs exhibit excellent hardness and its hardness increases significantly with the increase of titanium content. The wear mechanism changes from both of predominantly delamination and accompanied oxidative wear to single delamination wear, which is due to ultra-high melting point and high hot hardness of TiN, that can effectively prevent the oxidation and deformation of the worn surface. Formation of the ceramic coatings containing the TiN second phase and TCP phase are the key factor to AlCrFeNiTix alloy with the excellent hardness and wear properties.

Acidic corrosion-abrasion resistance of concrete containing fly ash and silica fume for use as concrete floors in pig farm

The objective of this study is to investigate the resistance of concretes to organic acid corrosion and abrasive corrosion, which occurs in typical pig farms. For the concrete mixtures, cement was replaced by fly ash and silica fume with different weight percentages up to 30%. The cubic mortar and concrete specimens were prepared and tested for compressive strength and mass loss due to organic acid corrosion. The test results indicated that fly ash and silica fume mixed together significantly enhance the compressive strength of the concrete, especially at long-term curing periods. The resistance of the concrete and mortar against organic acid corrosion was greatly improved by the substitution of fly ash and silica fume. Moreover, two testing machines were developed to simulate the abrasion-corrosion attack on concrete floors in pig farms (one for organic acid corrosion tests in wet-dried conditions and the other one for an abrasion testing machine with steel brushes). The concrete slab was cast and tested with a wet-dry switching system in an organic acid solution cooperating with an abrasion test. The test results demonstrated that applying a large amount of fly ash and silica fume is not effective for increasing the resistance of the concrete against organic acid corrosion and abrasive corrosion. The concrete mixture with 5 wt% of silica fume shows the highest resistance to organic acid corrosion together with abrasive corrosion with a mass loss reduction for 7.14% compared to the reference mixture.

Grey-Taguchi optimization of mechanical and abrasive wear properties for cotton grass fiber reinforced epoxy composites

ABSTRACT In this investigation, an effort has been made to analyze the abrasive wear characteristics of cotton grass (CG) reinforced epoxy composites through the hand layup technique. The abrasive wear test is conducted on a dry sand abrasion test machine based on ASTM G65; according to this, the specimen is fabricated with a dimension of 76 × 25 mm2. The engineering application for the composites requires that it should have high wear resistance, low water absorption, and robust strength. Mechanical properties such as tensile strength, hardness, and impact energy are experimentally investigated and optimized and the optimum results are obtained at 9 wt% of CG contents with magnitude of tensile strength of 45.81 MPa, hardness of 34.17 Hv, and impact energy of 2.2 J. The multiple responses of composites are analyzed using the Gray–Taguchi method and optimal factors settings to improve multiple responses, i.e., abrasive wear rate, water absorption, tensile strength, hardness, and impact energy. The results showed that the most critical factor influencing the properties of composites is CG content (9 wt%), accompanied by sliding velocity (96 m/s), normal load (15 N), and sliding distance (60 m). Scanning electron microscopy is used to analyze the composites’ worn surfaces to investigate the potential wear mechanism.

Considerations for the selection of interim restoration materials using wear test results.

The purpose of this study was to examine the wear of resin materials using two-body wear tests and to verify a selection method for optimal interim restoration materials from findings of a diagnostic occlusal device. Specimens were prepared from nine different resins used for diagnostic occlusal devices (soft resin) and interim restorations. Wear tests were conducted using an abrasion testing machine. The resulting wear on resin specimens and antagonist stainless-steel styluses was measured using a laser confocal scanning microscope, and the surface conditions were observed through a scanning electron microscope. The data were analyzed with one-way ANOVA and Tukey's multiple comparison test. The findings of the previous study on diagnostic occlusal devices were referred to in order to verify the selection method of optimal interim restoration materials. The maximum wear depth of the soft resin specimens was significantly greater than that of the other specimens (p<0.05) and was equivalent to the wear depth of a diagnostic occlusal device used for 14 nights. The wear of bis-acryl resin material was shallower than that of the other materials (Polymethyl methacrylate and polyethyl methacrylate), and its antagonist stylus was significantly worn (p<0.05). The findings of the previous and present studies showed a relationship among the parameters of Electromyography, wear depth of the diagnostic occlusal device, and wear of materials used for interim restorations. Findings related to bruxism can guide in the selection of interim restoration material and the determination of a suitable duration of wear.

Alterations to Titanium Surface Depending on the Fluorides and Abrasives in Toothpaste.

Fluoride and abrasives in toothpastes may cause corrosion and deterioration of the titanium used for implants and other prostheses. The purpose of this study was to investigate how the presence or absence and types of fluoride and abrasives affected the titanium surface texture. Brushing with toothpastes was performed on pure-titanium discs using an abrasive testing machine. Unprocessed titanium discs without brushing were used as control samples. Surface roughness, color, and gloss of titanium were measured and the differences compared with the control were analyzed. Additionally, titanium surfaces and abrasives in toothpastes were observed using a scanning electron microscope to compare the surface texture of each sample. Some toothpastes (abrasive+) significantly increased the difference in surface roughness, color, and gloss, compared with ultrapure water. Toothpaste (fluoride+/abrasive+) that had many polygonal abrasive particles led to the largest color differences and exhibited notable scratches and a larger number of contaminant- or corrosion-like black spots. In contrast, brushing with toothpaste without fluoride or abrasives (fluoride−/abrasive−) caused little change to the titanium surface. These results suggest that both fluoride and abrasives in toothpaste used for brushing may be factors that affect surface texture and corrosion resistance of titanium.

Improving Study on Wear Resistance and Mechanical Properties of Graphene / Polyurethane Microfoam Composites

Modified reduced graphene oxide (rtgo) was prepared by using γ - isocyanate propyl triethoxysilane (IPTS) as modifier. Graphene / polyurethane nanocomposites were prepared by in-situ polymerization. Graphene / polyurethane composites were characterized by scanning electron microscopy, TGA, DIN abrasion and electronic universal testing machine. The effects of different reaction formulations and graphene addition on the wear resistance and mechanical properties of the composites were studied. The results show that the wear resistance and tear resistance of the composite can be greatly improved after the functional graphene is compounded with polyurethane.

Strength properties of ballast layer, created from new and recycled crushed stone ballast

The objective of the research is a railway ballast layer created from new and recycled ballast particles in different ratio. In order to study the possibility of using recycled ballast grains in ballast layer, it is necessary to carry out laboratory triaxial tests of ballast crushed stone with size of the particles 25-60 mm with different grain shape. Abrasion testing machine allows to reach the effect on new ballast, which is similar to abrasion of ballast particles in the railway track. Therefore, it is possible to create ballast samples from (new) mixed and recycled ballast and estimate which proportion has the strength characteristics, which are close to the ones in ballast layer created only with new ballast particles. The result of the study shows, that it makes sense to return the recycled crushed stone in a mix with a new one in order to reduce the cost on a railway maintenance.

Design of Pin-on-Disk Type Abrasion Testing Machine for Durability Assessment of Rock Cutting Tools

Design of Pin-on-Disk Type Abrasion Testing Machine for Durability Assessment of Rock Cutting Tools

Wear of sprag clutch wedge in overrun state under high temperature condition

A formula is proposed based on Archard’s wear model to calculate wedge wear depth in a positive continuous engagement (PCE)-type sprag clutch with double-disc inner cam wedge in the overrun state. Methods to solve for the equation parameters are proposed. Using a sprag clutch with an M50 steel wedge as an example, wedge wear depth variation over time under high temperatures was analyzed. An easy-to-clamp wedge was designed and a high-temperature abrasion testing machine was used to test the wedge. The worn surface profile was observed using a three-dimensional profiler and the wedge wear depth was obtained. The effects of lubrication, temperature and speed on wear were analyzed using mixed-level orthogonal experimental design. Results show that the theoretical values are consistent with test values. Therefore, the model can be used to calculate wear accurately for the overrunning sprag clutch. Lubrication affects wear depth significantly, whereas temperature has a smaller effect and speed has very little influence. Within the experimental scope, when the temperature increased by 1°C, the wear depth increased by approximately 0.0145 μm and when the speed increased by approximately 1 time/minute, the wear depth increased by 0.00854 μm. These results provide theoretical support for optimal sprag clutch design.

Improvement of the Tribological Properties and Corrosion Resistance of Epoxy–PTFE Composite Coating by Nanoparticle Modification

In order to meet the requirements of high corrosion resistance, wear resistance, and self-lubrication of composite coatings for marine applications, epoxy matrix composite coatings containing PTFE and TiO2 nanoparticles were prepared on the steel substrate. With silane coupling agent KH570 (CH2=C(CH3)COOC3H6Si(OCH3)3), titanium dioxide nanoparticles were modified, and organic functional groups were grafted on their surface to improve their dispersion and interface compatibility in the epoxy matrix. Then, the section morphology, tribological, and anticorrosion properties of prepared coatings, including pure epoxy, epoxy–PTFE, and the composite coating with unmodified and modified TiO2, respectively, were fully characterized by scanning electron microscopy, friction–abrasion testing machine, and an electrochemical workstation. The analytical results show that the modified TiO2 nanoparticles are able to improve the epoxy–PTFE composite coating’s mechanical properties of epoxy–PTFE composite coating including section toughness, hardness, and binding force. With the synergistic action of the friction reduction of PTFE and dispersion enhancement of TiO2 nanoparticles, the dry friction coefficient decreases by more than 73%. Simultaneously, modified titanium dioxide will not have much influence on the water contact angles of the coating. A larger water contact angle and uniform and compact microstructure make the composite coating incorporated modified TiO2 nanoparticles show excellent anti-corrosion ability, which has the minimum corrosion current density of 1.688 × 10−7 A·cm−2.

Effect of abrasion and chemical treatment of recycled aggregate on the workability, strength, and durability properties of concrete

Different treatment strategies have been explored in a quest to improve the properties of recycled aggregate concrete (RAC). The improvement strategies are directed towards the removal of residual layers of old mortar on the recycled coarse aggregate (RA). The removal of old mortar layer improves the bond between the new mortar and the RA that makes the quality of RAC better. Efforts have been made to remove the old mortar from the surface of the RA through abrasion process, however, there is a lack of detailed information, particularly about the beneficial effect of abrasion coupled with some chemical treatment. In the present work, the performance of RAC prepared with the RA subjected to abrasion (with the help of a Los Angeles abrasion test machine) was evaluated. The combined effect of abrasion and sodium silicate treatments of the RA on the fresh and hardened properties of RAC was also evaluated. A significant improvement in the workability, strength, and durability of RAC was noted due to abrasion treatment of the RA. Strength and durability of RAC increased significantly due to the combined effect of abrasion and sodium silicate treatment of the RA.

Study on a novel antibacterial light-cured resin composite containing nano-MgO

A new type of photocurable resin composite containing nano-MgO was synthesized in order to reduce the occurrence of secondary caries. Different mass ratios (0 %, 1 %, 2 %, 4 %, 8 %) of nano-MgO were added into resin composites. The antibacterial properties of nano-MgO powder and modified resin composites against Streptococcus mutans (S. mutans) were detected by antibacterial ring test and film contact test, respectively. Compressive strength (CS) and wear resistance were determined by a universal testing machine and an abrasion test machine. The results indicated that antibacterial activity and wear resistance of resin composites containing nano-MgO were superior to the control group (p < 0.05). The antibacterial rate reached as high as 99.4 % when the mass ratio of nano-MgO was 8 %. However, the CS values tended to decline as the content of nano-MgO increase. Hence, the addition of nano-MgO showed excellent antibacterial property to resin composites and enhanced wear resistance, but was detrimental to their mechanical properties.

Influence of Thermal Environment on Simulation State of Abrasion Tester and Compensation Method

Abrasive testing machine can effectively evaluate the wearability of sealed coatings for aircraft engines. High temperature, high speed and harsh working conditions have brought difficulties to the development of testing machines, At the same time, it brings motion error to the test machine feed system. This paper analyzes the error brought by the high temperature environment to the feeding system of the testing machine, and proposes an evaluation and compensation method. Through experimental verification, the method can effectively eliminate the experimental error caused by temperature and evaluate the wearability of the seal coating. Laid the foundation of research and provided accurate test evaluation conditions.

Development of Temperature-controlled and Humidity-controlled three-body Abrasive Wear Testing Machine based on MLD-10 Dynamic Abrasive Wear Testing Machine

In order to simulate engineering machinery (such as mining machinery, feed pellet machine, building machinery and so on), which existence of different degrees of high temperature and humid corrosion three-body abrasive wear behavior in the laboratory environment. In view of the current three-body abrasive wear testing machine cannot simultaneously take into account the composite conditions characteristics of the three-body abrasive wear behaviour, high temperature and humidity, and make the optimization design, based on the MLD-10 dynamic abrasive wear tester. It includes corrosion and wear groove, fluid medium, temperature measuring and controlling device, stirring device, etc. A three-body abrasive wear testing Machine that can control temperature and humidity. Subsequently, the simulated working condition test of the ring die of feed pellet machine were carried out. The test results show that the wear appearance of the test sample is basically consistent with that of the real ring die of feed pellet machine. It indicates that the developed testing machine can simulate the high temperature and humid three-body abrasive wear behavior, and has good reliability and applicability.

Wear resistance of Ni-Co/SiC composite coating by jet electrodeposition in the presence of magnetic field

The Ni-Co/SiC composite coatings were prepared via jet electrodeposition in the presence of magnetic field. The microstructure and texture orientation of the composite coatings were analyzed via field emission scanning electron microscopy, three-dimensional profiling, and X-ray diffraction. The microhardness and wear resistance were characterized by a microhardness tester and a friction–abrasion testing machine. The results indicated that nano-SiC particles improved the surface morphology of the Ni-Co/SiC composite coating. In jet electrodeposition, globular structure aggregation began to form protrusions in the Ni-Co/SiC composite coating due to nanoparticle agglomeration when 6 g/L of nano-SiC was added. The Ni-Co/SiC (6 g/L) composite coating became uniform and densification by jet electrodeposition in magnetic field, with higher microhardness and better wear resistance. The microhardness of the Ni-Co/SiC composite coating increased to 626 ± 14 HV, and the corresponding friction coefficient was as low as 0.317.

Effect of B Content on Microstructure and Wear Resistance of Fe-3Ti-4C Hardfacing Alloys Produced by Plasma-Transferred Arc Welding

The Fe-3Ti-xB-4C (x = 1.71, 3.42, 5.10, 6.85 wt. %) hardfacing alloys are deposited on the surface of a low-carbon steel by plasma transferred arc (PTA) weld-surfacing process. Microstructure, hardness and wear resistance have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), Rockwell hardness tester and abrasive wear testing machine, respectively. The results show that the microstructure in all alloys is composed of austenite, martensite, Fe23(C,B)6, Ti(C,B) and Fe2B. The volume fraction of eutectic borides and Ti(C,B) carbides increases with increasing B content. Many brittle bulk Fe2B phase arises when the boron content increases to 6.85%, which causes the formation of microcracks in the hardfacing layer. The microhardness of the hardfacing alloys is significantly improved with the B addition, however, the wear resistance of hardfacing alloys increases firstly and then decreases with increasing of B content. The hardfacing alloy with the 5.10% B content has the best wear resistance, which is attributed to high volume fraction of eutectic borides and fine Ti(C,B) particles distributed in the austenite and lath martensite matrix with high hardness and toughness. The formation of brittle bulk Fe2B particles in the hardfacing alloy with the 6.85% B leads to the fracture and spalling of hard phases during wear, thus, reducing the wear resistance.

Optimization of arc-sprayed iron-based tungsten carbide hard coatings on harvester blades

This research investigated the viability of improving the performance of agricultural harvester blades by thermal spray, utilizing the arc spray process. A cored iron-based wire with recycled WC was used with several process parameters in order to determine the best WC distribution in the coating. The effect of 40 V voltage was compared to 30 V on electric arc-sprayed coatings, and the results show that 40 V provides higher tungsten carbide (WC) content. Flame remelting of the arc-sprayed iron-based WC coatings on sugarcane harvester blades was studied, and the changes in the microstructure and impact abrasion wear behavior were analyzed. The coatings were characterized by utilizing microstructural analysis and microhardness indentation tests. In order to verify the coating adhesion strength, a special machine was built to simulate field conditions. This machine, called impact abrasion test machine, was used to test the blades for coating detachment due to low adhesion strength. The results showed that the flame remelting provided metallurgical bonding between the coating and substrate, improving the impact wear resistance and potentially extending the lifetime of sugarcane harvester blades.