Micro-scale Abrasive Wear Research Articles

Study on the Influence Law of Micro-Scale Abrasive Wear on a Wind Turbine Brake Pad

The hard particles in the copper-based powder metallurgic material of a brake pad for a wind turbine brake falls off and presses into the surface of the brake disc to form abrasive particles under high-speed and heavy-load working conditions. The presence of abrasive particles will produce abrasive wear with micro-scratch and micro-scribe on the copper-based material of the brake pad. The critical scratch depth effect in the abrasive wear process is proposed based on the critical depth effect of the metal removal process at the micro-scale. The abrasive wear is divided into two types: scratch wear and scratch wear, which is proposed according to the comparison of the actual scratch depth and the critical scratch depth. The range of braking speeds and friction coefficients in abrasive wear is determined by the recommended parameters of the disc brake. The ABAQUS2020 software is used to simulate and analyze the micro-scale abrasive wear of a brake pad. The brake strain/stress curves of the brake pad under different brake speeds and friction coefficients are compared and analyzed for two abrasive wear types based on the range of braking parameters, and the key factors affecting abrasive wear are proposed.

Influence of austenitising temperature on micro-scale abrasive wear of Ni-modified ferritic stainless steel

Influence of austenitising temperature on micro-scale abrasive wear of Ni-modified ferritic stainless steel

Effects of niobium and molybdenum addition on microstructural characteristics and wear properties of 14 wt%Cr white cast irons

White cast iron (WCIs) alloys were developed by adding Nb, Mo, and a combination of both (∼3 wt% Nb, ∼3 wt% Mo, ∼1 wt% Mo-2 wt% Nb) through melting and casting. The objective was to analyze the microstructural characteristics of the alloys, as well as the impact of reinforcing carbides on their mechanical and tribological properties. The alloy containing the highest percentage of niobium exhibited a refined microstructure, tending towards a eutectic structure, unlike the Mo-containing materials with totally hypoeutectic microstructures. The microstructural characteristics of the alloys and morphology of niobium carbides, as well as the percentage of M7C3 eutectic carbides produced were affected by the varying percentages of Nb and the Mo–Nb combination. Moreover, thermodynamic simulations revealed that the NbC carbide precipitated before the M7C3 eutectic carbides, austenite dendrites, and the MC (composed mainly of Nb containing bound Mo) carbide resulting from the Mo–Nb combination. The alloys containing Mo had similar bulk hardness values, while the alloy with the highest percentage of Nb showed a higher bulk hardness value. This was attributed to the effect of Nb on microstructure refinement and on the production of M7C3 eutectic carbides from the alloy. Although there were different reinforcing carbides (NbC, MC and M2C), the differences in microstructural characteristics had no noticeable influence on the Charpy impact energy. Micro-scale abrasive wear test (conducted with SiC abrasive slurry) demonstrated that the reinforcing carbides MC and mainly NbC had a beneficial effect in blocking and preventing the progression of continuous micro-cuttings and formation of grooves. The M7C3 and M2C carbides were less effective at protecting the matrix against the high-hardness SiC abrasive.

Micro-Scale Abrasive Wear Resistance of a Nanoceramic Sealant Applied on Galvanized Low Carbon Steel

The idea for this work came from a market need to obtain coatings or sealants that would extend the useful life of metallic materials in applications that involve exposure to corrosive environments. The main objective of the nanoceramic sealant studied in this work is to extend the life of metallic fasteners. To evaluate the performance of the sealant from other perspectives, microstructural analysis, adhesion test, micro-scale abrasive wear tests and corrosion test were carried out. These tests were performed on samples coated only with white zinc, which is commonly used in the fastener industry, and on samples coated with white zinc followed by application of the nanoceramic sealant. The application of the nanoceramic sealant contributed to the improvement of corrosion resistance and reduction of the corrosion rate. The corrosion rate of the sample coated with the sealant reduced by 62.2% when compared to the sample that only went through the white zinc coating process. The coating showed low adhesion to the substrate with the presence of severe delamination and microcracks. This feature contributed to the low wear resistance presented by the coating under the conditions studied in this work. Less attention, compared to studies involving corrosion resistance, has been given to wear resistance in the fastener industry. The results obtained in this paper show that the study of tribological behavior is an important factor in increasing the efficiency of fasteners applied in harsh environments.

Comparative Micro-Scale Abrasive Wear Testing of Thermally Sprayed and Hard Chromium Coatings

Nowadays, due to the carcinogenic effects of chrome, replacing the hard chromium used for hydraulic components like rods and cylinders is becoming increasingly requested. Thermally sprayed coatings are a solution to the problem; however, proper understanding and characterisation of their tribological behaviour are essential for the successful exploitation of surface engineering. Thus, the main aim of this study is to evaluate the abrasive wear characteristics of two metal sprayed layers, tungsten carbide (WC) deposited through the high-velocity oxygen fuel coating (HVOF) method and Fe alloy coating deposited through thermal spraying with an electric arc with a wire-electrode G3Si1, and compare the results with those of an electrochemically deposited hard chromium layer. Their wear resistance is then related to their hardness. The results highlight the tribological performances of the thermally sprayed coatings. The HVOF WC10Co4Cr coating has a wear coefficient and a material wear volume that are hundreds of times lower than those of the other two coatings.

Influence of plasma nitriding treatment on the micro-scale abrasive wear behavior of AISI 4140 steel

• Nitriding treatment leads to a reduction in the volume of wear and the specific wear coefficient. • Nano nitrides phases formed on the surface of the material. • Microstructural parameters and the number of phases influence the micro-abrasive wear behavior. • The hard layer of nitrides increased the AISI 4140 steel hardness more than 2.5 twice. Plasma nitriding was performed on AISI 4140 steel for various times. Untreated and plasma nitrided AISI 4140 steel were microstructurally, mechanically and tribologically characterized. The nitrided compound layer, consisting of ε-Fe 2-3 N and λ-Fe 4 N phases, was approximately of 5.0 μm thick. Microhardness of treated steel for 3 h was significantly higher than that of the untreated. The ball cratering test revealed that abrasivity of the treated samples decreased with the nitriding time due to an increasing in micro-strain values, quantify of nitrided phases, and the formation of nanocrystalline size of nitrides.

Combined effect of abrasive particle size distribution and ball material on the wear coefficient in micro-scale abrasive wear tests

Micro-abrasive wear tests were carried out to analyze the combined effect of abrasive particle size distribution and ball material on the wear coefficient. Different particle size distributions were obtained by mixing different fractions of two silicon carbide (SiC) abrasive powders, having average particle sizes of 6.0 μm and 14.4 μm. Tests were conducted using two different normal loads, 0.2 and 0.4 N, AISI 1020 steel samples and balls made of AISI 52100 martensitic steel, AISI 304 austenitic stainless steel, polyurethane rubber and zirconia-alumina. Worn surfaces were analyzed with Scanning Electron Microscopy (SEM) and by optical profilometry. Results have indicated that a change in ball material, with consequential modification in the ratio between the hardness of the body and the counter-body, enabled different behaviors of the wear coefficient with the variation of the granulometric distribution. Such differences are due to the ability of the particles to be embedded and dragged into contact. The wear coefficients were analyzed in each case, resulting in a map to describe the combined influence of granulometric distributions of abrasive particles and ball material on the wear coefficient.

Case study: Abrasive capacity of Limnoperna fortunei (golden mussel) shells on the wear of 3 different steel types

The impact of particles suspended in the water is responsible for the wear of mechanical surfaces in hydraulic systems. The characteristics and concentrations of these particles in the flow directly influence the intensity of the abrasion processes. Within this context, knowledge of the abrasive power of a particle is of great importance. It is known that an invasive species, known as golden mussel shell, has become embedded in several hydroelectric plants of the South and Southeast of Brazil, provoking an increase of the wear caused by shells that pass through the hydraulic system. In this context, the abrasive capacity of ground golden mussel shells on the three metallic materials used in the labyrinth component of the hydraulic turbines was analyzed. To determine the wear pattern and the relationship of the specific wear coefficient of the material (k), due to the increased concentration of golden mussel shell, micro-scale abrasive wear tests were performed on three different steel plates using abrasive suspensions at different concentrations of ground golden mussel shell in distilled water. The abrasivity of the golden mussel shell was also compared with the abrasivity of silicon carbide (SiC), commonly used as standard material in microabrasion tests. The analyses showed that the golden mussel shell is around 16 times less abrasive than the silicon carbide, taking into account the average obtained for the three different materials tested. In addition, the wear mechanisms acting on the SiC tests and those with the golden mussel shell were the same.

Microabrasive wear behavior of borided steel abraded by SiO2 particles

Boriding treatment was applied to AISI 1020 steel to improve its wear resistance. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy, Vickers microhardness testing, fracture toughness, and confocal microscopy. The microscale abrasive wear behavior was also investigated. SiO2 abrasive particles were used as abradant with slurry concentrations of 0.5 and 1.0g/cm3. Normal loads of 0.49 and 0.98N were used. Fe2B phase was identified in the boride layer via XRD analysis. The Fe2B layer was 169μm thick with a mean hardness of 1608±101 HV0.05 and fracture toughness of 5.35±1.43MPam1/2. A reduction in the hardness of the outermost surface of the boride layer was observed owing to the formation of a porous region. Boriding treatment improved the wear resistance of the steel substrate. Sliding abrasive wear was the main mechanism under all tested conditions. The presence of micro-rolling abrasion and fracture-based mechanisms was observed for untreated and borided samples, respectively.

Case study: Effects of sediment concentration on the wear of fluvial water pump impellers on Brazil's Acre River

The most important factor causing surface wear in hydraulic systems is the impact produced by abrasive particles suspended in the water flow. The impact conditions, such as mean particle velocity; particle mass; abrasive particle concentration in the liquid flow (number of particles per unit of liquid volume, size distribution of the particles); angle of attack at which the particles collide with the surface; and duration of the effect produced by the particles on the surface contribute to the development of the abrasion process. The wear resistance of the centrifugal pump impellers depends on the characteristics of the materials used in their manufacture and the abrasiveness of the suspended sediments in the pumped water. Despite special care in choosing the material used in its manufacture, abrasive wear is practically impossible to totally avoid. This work analyses the wear of ductile cast iron impeller blades of a centrifugal pump, used at the Fluvial Water Elevation Station (FWES) of the Acre River sedimentary basin in Brazil, due to the sediment concentration variation and the river water level. To determine the wear pattern and the relationship between the material and specific wear coefficient (k) due to increased sediment concentration, a ball-cratering microscale abrasive wear test was performed on samples of ductile cast iron, withdrawn from a used impeller, and abrasive suspensions at concentrations of 1, 2, 3, 5 and 10 g L−1 of river sediment in distilled water. The wear volume to the impeller blades due to the relative velocity of the mixture (water + sediment) and the wear accumulated in an annual hydrological cycle were estimated mathematically. The results showed that: i) the k remains constant regardless of the normal force (FD) applied in the tests in the abrasometer; ii) the wear tests showed the abrasive capacity of the sediments at different concentrations; and iii) the rotational control of the pump speed based on the sediment concentration and the river water level can contribute to a reduction in wear of up to 30% considering the hydrological cycle.

Micro-Scale Abrasive Wear Testing of CrN Duplex PVD Coating on Pre-Nitrided Tool Steel

Specific wear rates were calculated from a series of micro-scale abrasive tests by means of the calotte-grinding method. The tested material was a CrN coating deposited by arc evaporation on ion-nitrided AISI H13 steel. Characterizations included: phase analysis, chemical composition, metallography, microhardness, micro-scratch resistance and nano-indentation hardness. On wear testing, the counter body was a 30 mm diameter steel ball rotating at a tangential speed of 9.42 m/min and normal load of 0.54 N. The abrasive was a mono-crystalline diamond micro abrasive paste, 1 micrometer grit. Wear volumes were calculated by measuring the wear scars at various test intervals. In non-perforating tests, Archard's wear equation was directly employed for calculating coating wear rate as the slope of the linear least square data fit. In perforating tests, Allsopp's method was employed for the simultaneous determination of coating and substrate wear rates, from the slope and intercept values of the linear least square data fit. Coating specific wear rate values obtained from both non-perforating and perforating tests were very consistent, with a relative difference within 6%. Relative errors in specific wear rate values were estimated to be of the order of 0.05 for the coating and 0.2 for the substrate.

Micro-scale abrasive wear of some sealing elastomers

This work aims to investigate the micro-abrasive wear of some common sealing elastomers by the micro-scale abrasion test. It has been employed to try hard materials, such as: mild steel, Cr-white cast iron, aluminum alloys, tool steel, polymers, etc, since it exhibits good accuracy and repeatability, however, it has not been implemented to test elastomers. In dynamic seals, micro-abrasive wear is produced because hard micro-debris are dragged by the lubricant film to the sealing interface during the machine operation, which accelerates the normal lubricated sliding wear. In order to see the capability of the micro-abrasion test to evaluate sealing elastomers, four materials were tried under different loads and progressive sliding distances using a TE66 micro-scale abrasion tester. The morphology of the wear scars was studied by SEM images. Hence, particular micro-abrasive wear patterns were found. Also, the wear volumes were assessed by optical profilometry since some scars did not met spherical caps as those occurred in hard materials. Thus, the test was effective to reproduce localized and consistent scars with micro-abrasion features by conducting short experiments, meaning it could be potentially used as an accelerated wear method for the characterization of sealing elastomers.

Wear study of Innovative Ti-Ta alloys

In this paper a wear study of innovative Ti-Ta alloys is present. Samples of Ti-30%Ta, Ti-52%Ta, were produced by laser cladding. This technology uses a high power density generated by a laser beam to melt the base material and the filler material. The interaction between the laser and the substrate is a function of the radiation absorption properties of the material and that conditions the heat flow. Laser technology allows working with high temperatures and melting powders of titanium and the alloying elements as tantalum. As this is a continuous process enables rapid cooling of the molten material and the consequent solidification. The principal importance of these innovative alloys is the low Young’s Modulus, the closest to Young´s Modulus of the bone, the biocompatibility of titanium and tantalum and consequently its applicability to biomedical industry. The wear behavior is an important factor that influences the structural integrity of materials and must be studied for innovative alloys. So in this work the micro-scale abrasive wear tests were used to characterize the wear behavior of Ti-30%Ta, Ti-52%Ta alloys. The results shows that the wear volume increases linearly as the rotation of the ball test and with the sliding distance and the analysis of the ball cratering shows that for this test there just grooving abrasion and the volume wear abrasion is higher for the highest hardness alloy.

Influence of load and sliding distance on the micro-scale abrasive wear behavior of TZNT alloy

The micro-scale abrasive wear behavior of TiZrNbTa (TZNT) alloy in Hank’s solution and distilled water was studied using the TE66 machine. The effect of load and sliding distance was considered. The results of experiments show that the wear volume of the TZNT alloy is increased with increasing distance because of the greater damage, but the wear volume is not present the same regularity as the increase of load due to the effect of several factors. Only three-body abrasive wear is present at the lower load, while the mixed wear mechanism includes three-body and two-body abrasive wears at the higher load. Through observation, the wear appears under the same sliding distance at various simulated body fluids. The wear appearance is related to the wear mechanism. For wastage map, under the conditions of this paper, the majority of the area is medium wastage, the rest is low wastage, and there is no high wastage. The wastage map is related to the wear volume of the alloy under different conditions.

Effect of abrasive particle size distribution on the wear rate and wear mode in micro-scale abrasive wear tests

In this work, the particle size distribution of two powders was initially analyzed, indicating an approximately normal (Gaussian) distribution with average particle size on the order of 2μm in one case and 6μm in the other. Both powders were composed of silicon carbide (SiC) particles. The two original powders were then mixed with different mass fractions, providing a series of SiC powders that were used in micro-scale abrasive tests with fixed-ball configuration. The wear tests were conducted on ASTM 1020 carbon steel and results were analyzed in terms of wear rate as well as wear mode (“rolling abrasion” or “grooving abrasion”). Results have indicated that the mass fraction of the original powders has a significant effect on the wear modes observed at the micro-scale level and that the wear rate does not follow a direct relationship with the mass fraction of the powder with larger average particle size.

Micro-scale abrasive wear behavior of medical implant material Ti–25Nb–3Mo–3Zr–2Sn alloy on various friction pairs

The micro-scale abrasion behaviors of surgical implant materials have often been reported in the literature. However, little work has been reported on the micro-scale abrasive wear behavior of Ti–25Nb–3Mo–3Zr–2Sn (TLM) titanium alloy in simulated body fluids, especially with respect to friction pairs. Therefore, a TE66 Micro-Scale Abrasion Tester was used to study the micro-scale abrasive wear behavior of the TLM alloy. This study covers the friction coefficient and wear loss of the TLM alloy induced by various friction pairs. Different friction pairs comprised of ZrO2, Si3N4 and Al2O3 ceramic balls with 25.4mm diameters were employed. The micro-scale abrasive wear mechanisms and synergistic effect between corrosion and micro-abrasion of the TLM alloy were investigated under various wear-corrosion conditions employing an abrasive, comprised of SiC (3.5±0.5μm), in two test solutions, Hanks' solution and distilled water. Before the test, the specimens were heat treated at 760°C/1.0/AC+550°C/6.0/AC. It was discovered that the friction coefficient values of the TLM alloy are larger than those in distilled water regardless of friction pairs used, because of the corrosive Hanks' solution. It was also found that the value of the friction coefficient was volatile at the beginning of wear testing, and it became more stable with further experiments. Because the ceramic balls have different properties, especially with respect to the Vickers hardness (Hv), the wear loss of the TLM alloy increased as the ball hardness increased. In addition, the wear loss of the TLM alloy in Hanks' solution was greater than that in distilled water, and this was due to the synergistic effect of micro-abrasion and corrosion, and this micro-abrasion played a leading role in the wear process. The micro-scale abrasive wear mechanism of the TLM alloy gradually changed from two-body to mixed abrasion and then to three-body abrasion as the Vickers hardness of the balls increased.

Wear resistance performance of thermally sprayed Al3Ti alloy measured by three body micro-scale abrasive wear test

Thermally sprayed aluminium alloys are often used as coatings to protect steel structures from corrosion. However, in many applications the alloys also need to be sufficiently wear resistant to prevent premature removal of the coatings. The addition of titanium to sprayed aluminium coatings is one approach to enhance the wear resistance. In this study the wear performance of a newly developed and commercially available aluminium coating with 3wt% Ti was studied in terms of its microstructure, hardness and wear resistance. Micro-scale abrasive wear tests were conducted on the pre-sprayed alloys, and the arc sprayed coatings produced from these alloys in order to determine the influence the spraying process has on the structure and wear properties of the coatings. The wear performance of the coatings with Ti was compared with a 99.5wt% Al coating, a thermally sprayed 13% Cr steel coating and with the mild steel substrate.Significant changes were observed in the microstructure of the sprayed coatings when compared with pre-sprayed alloys. The aluminium with 3wt% Ti coating exhibited a large increase in its hardness value compared with the pre-sprayed alloy and it was significantly harder than the 99.5wt% Al coating. It was observed that under micro-scale abrasive wear test conditions, the coefficient of wear of the coating with 3wt% Ti was 33% lower than that of the 99.5wt% Al coating and it was approximately the same as that of the 13wt% Cr steel coatings.

Effect of laser surface modification on the micro-abrasive wear resistance of coated cemented carbide tools

The use of surface texturing on the rake face of a tool can modify the tribological phenomena present at the chip-tool interface. Many different wear mechanisms, including abrasive wear, occur at the tool during machining. The presence of hard phases in the workpiece material, as well as hard particles removed from the tool, can generate abrasive wear on the tool surfaces. The objective of this work is to study the abrasive wear resistance of micro-textured tools in comparison to conventional (commercial) cutting tools. Square cemented carbide inserts containing a three-layered coating (TiCN–Al2O3–TiN) were textured using two different linear patterns, perpendicular and parallel to the direction of the chip movement. Microabrasion and machining tests on both textured and commercial tools were carried out. Turning tests were carried out for ABNT/AISI 1050 steel under severe cutting conditions with overhead application of cutting fluid. In order to simulate the abrasive wear mechanism that can occur on the tool surface, a free ball microabrasion test was used under a suspension of silicon carbide particles and distilled water. The abrasive wear mechanisms were observed using SEM. The micro-scale abrasive wear resistance of laser micro-textured cement carbide tools was compared to untextured tools. For the turning tests, texturing increased the tool life, which was determined when the wear at the tool flank achieved a specified value. On the other hand, for the microabrasion tests, laser texturing resulted in a pronounced increase in the coating wear rate. This fact was connected to the decrease of coating hardness caused by laser texturing. Therefore, the increase of tool life in the turning tests was not related to a reduction of abrasive wear on the tool flank. Probably, it was caused by other tribological conditions that were not represented in microabrasion tests, for example: the presence of cutting fluid in the environment and elevated contact temperatures.

Tribological enhancement of AISI 420 martensitic stainless steel through friction-stir processing

Friction Stir Processing (FSP) has been used to modify the microstructure and properties of AISI 420 stainless steel. The effects of FSP on the steel's microstructure, hardness and wear resistance have been measured and compared with the properties of a conventionally hardened AISI 420 and with D2 tool steel. Optical microscopy, X-ray diffraction and micro-hardness have been used to characterise the steel, and two types of wear tests; dry reciprocating ball-on-flat and micro-scale abrasive wear testing, have been used to determine the processed steel's wear performance under two quite different wear mechanisms. The results show that FSP of AISI 420 can produce higher hardness (maximum HV0.3=722) and better wear performance than conventional heat treatments and in some regions better hardness and tribological performance than D2 tool steel. FSP appears to induce the austenite to martensite transformation within the AISI 420, but the resulting microstructures appear to be significantly different from the conventionally heat treated material.

Micro-Scale Abrasive Wear of Soft Materials

Ball-crating micro-scale abrasion technique has been used to determine the specific wear rates of coating and substrate by only one set of tests done with the coated surface. It can also be used to test wear performance of bulk materials. Some micro-scale abrasive wear problems about soft bulk materials were investigated with multifunctional micro-wear tester by self-development. And it was compared with Ni60B coating and TiN coating having higher hardness. The formation and evolution of ridges of the abrasion scar on soft material surfaces have been studied. The formation mechanism of ridges was discussed and the influencing factors on the ridge formation were analyzed. Recommendations were made for the optimum test conditions for micro-scale abrasive wear investigation of soft materials.