Extreme Wear Research Articles

Microstructure and dry sliding wear evaluation of functionally graded coating deposited via atmospheric plasma spray

Surfaces are commonly enhanced with wear-resistant coatings to improve their resistance to abrasion, erosion, and other forms of wear. These coatings play a crucial role in extending the lifespan and improving the performance of materials and components exposed to challenging conditions. The objective of the current study is to deposit thermally sprayed 3-layer TiC–12Co–10ZrO2/NiCoCrAlMo functionally graded coatings on SS410 substrates using atmospheric plasma spray. The results revealed that by employing appropriate ceramic proportions, the microhardness of graded coatings increased to 990.4 HV, which is approximately 3.21 times higher than that of the substrate. Furthermore, the tribological properties of graded coating exhibited superior resistance compared to the substrate, where process settings were varied. Specifically, graded coating samples subjected to the applied load, sliding distance, and sliding velocity showed improved wear resistance of 78.51%, 68.42%, and 76.66% respectively in extreme conditions compared with uncoated samples. The characterization of the worn surface revealed a sequential occurrence of wear mechanisms: abrasive, adhesive, and delamination. The formation of TiO2 and Cr2O3 tribo-oxide film protects the surface against the wear mechanism and is applicable in extreme wear environments.

ВОССТАНОВЛЕНИЕ ВАЛА РОТОРА ТУРБОКОМПРЕССОРА ТКР-7С-6 ДВИГАТЕЛЯ ВНУТРЕННЕГО СГОРАНИЯ

The use of a turbocharger has a positive effect on the power of the internal combustion engine, reduces fuel consumption and positively affects the environmental friendliness of operation. Along with the positive effect on the operation of the internal combustion engine, turbochargers reduce the overall life of the engine. Small extreme wear and a small diameter of the rotor shaft limit the use of traditional recovery processes. (Research purpose). The research purpose is developing a method for restoring the rotor shaft of a turbocharger of internal combustion engines. (Materials and methods) A short-pulse laser surfacing of an antifriction ceramic coating with subsequent finishing treatment in the form of diamond smoothing was used to apply the restoration coating. The powder composition BN-B4C-LiO-MgO was used as a filler material. Preliminary studies have shown high adhesive strength of the coating and wear resistance in conditions of oil starvation. The surface was subjected to finishing treatment by diamond smoothing after the formation of the restoration coating. A laboratory installation has been developed to accelerate the rotor shaft in the turbocharger housing to 60,000 revolutions per minute, followed by an assessment of the acceleration time and the pressure increase in the compressor manifold. (Results and discussion) The presented method made it possible to restore the turbocharger rotor shaft with a surface roughness of Ra 0.32. Bench tests were conducted to evaluate the efficiency of a turbocharger with a restored shaft, the results of which showed that the intensity of unwinding of the turbocharger rotor shaft and the pressure increase in the compressor manifold are on average 10 percent higher than for a unit with a standard rotor shaft. (Conclusions) The presented technological process of restoring the worn surface of the rotor shaft of the 7C-6 turbocharger is of high practical importance and its application will improve the reliability and durability of turbochargers. The results can be used in the operating and repair enterprises.

The association of cobalturia with cobaltism symptoms a prospective blinded study of 229 post-arthroplasty patients.

Cobalt is a mitochondrial toxin, clinical cobaltism manifests with constitutional, neurologic, and cardiovascular symptomatology. Cobalt's severe toxidrome is known through case reports from extreme wear or corrosion of cobalt-chromium arthroplasty components. However, the spectrum and epidemiology of orthopedic-implant cobaltism and its relationship to duration and degree of cobalt exposure are not well defined. The relationship of urine-cobalt concentration and duration of exposure to cobalt-chromium joint implants and cobaltism symptomatology were prospectively studied in 229 patients. Subjects received a Cobaltism-Symptom-Inventory-Score (CSIS) based on a protocolized interview and examination followed by a spot urine-cobalt measurement. 129 (56%) subjects were cobalturic (urine-cobalt ≥1.0 ppb). 122 (53%) subjects had a CSIS of >2, this status significantly associates with cobalturia. Median [IQR] urine-cobalt in the subjects with a CSIS >2 was 4.1[1.1-17.0] ppb compared to 0.5[0.5-1.4] ppb in subjects with CSIS ≤ 2. Cobalturia has a sensitivity of 0.69, a specificity of 0.77, and a positive predictive value of 0.74 for a CSIS of >2. The product of years-exposed to a cobalt-chromium implant and urine-cobalt by quartiles significantly positively associates with the Cobaltism-Symptom-Inventory-Score. A urine-cobalt of ≥1 ppb likely indicates adverse systemic exposure to orthopedic-implant generated cobalt. Cobaltism severity as quantified by the CSIS significantly correlates with the product of spot urine-cobalt concentration and years-exposed to a cobalt-chromium orthopedic-implant indicating a dose-response relationship. Medical provider and public awareness of orthopedic-implant cobaltism is vital because tens-of-millions are at-risk and early cobaltism is reversible. Further use of cobalt-chromium orthopedic-implants should be questioned given cobaltism becomes clinically apparent at a spot urine-cobalt of 1 ppb or greater. Monitoring of patients with high-risk cobalt-chromium orthopedic-implants appears to be indicated.

A novel approach to the deposition of Co-Mo-Cr-Si coating on Haynes 282 by laser fusion and laser remelting

This paper presents a novel hybrid method of the crack-free fusion of CoMoCrSi, which is a cobalt-based alloy with molybdenum additions with the composition analogous to Tribaloy® T400, on Haynes 282 for parts where extreme wear is problematic with high temperatures and corrosive media, such as industrial turbine applications, commercial jet engines, and rocket engines. To alleviate cracking of the coating during laser surface deposition/coating, previous attempts relied on preheating of the substrate to reduce cracks to alleviate a thermal mismatch between the substrate and molten powder. The primary aim of this work is accomplished by fusing crack free CoMoCrSi layers using a novel hybrid process of combining laser cladding and laser remelting processes. The optimal process conditions of coating crack-free CoMoCrSi on Haynes 282 were determined for both the laser powderbed fusion and remelting processes. Microhardness and chemical compositions of the coating layers produced using optimal process parameters with and without remelting the substrate were compared. The chemical compositions of different phases present in the coating layer were analyzed by Energy Dispersive X-ray Spectroscopy (EDS). The remelting process yielded no dilution at the surface, resulting in the preservation of the original CoMoCrSi coating properties.

Analysis of Sound Emission Using Ternary Blend Fuel in Compression Ignition Engine

Alternative fuel is considered to be suitable oils in diesel engines, which are well known for their ability to diminish lubricant oil debris and noise emissions. A minute research has been done to examine the long-term effects of using blend fuel. In this study, two blend fuels: diesel and waste cooking oil (DF95WCO5), and diesel, waste cooking oil and n-pentanol (DF65WCO20Pe15) were chosen and compared with diesel fuel (DF) to investigate the impact of these blends on noise emission in diesel engine. In order to evaluate the kinematic viscosity and density and determine the effect on sound pressure levels, lubrication oil samples were taken throughout the test at intervals of 20 hours. A literature review was done for the current work's analysis of the literature on the noise emissions from diesel-waste cooking and n-pentanol fuel blends. When the engine was fueled with DF65WCO20Pe15 blend, the engine lubricating oil analysis revealed an extreme wear issue, decreased viscosity, and increased density values. The conclusion is that single cylinder diesel engines can use binary blend DF95WCO5 and ternary blend DF65WCO20Pe15 without any adjustments. DF65WCO20Pe15, in contrast to the reference fuel, achieved some superior outcomes.

Performance indicators of cutting tools from extra hard materials

Purpose. Establishing dependencies connecting the system of indicators of the processing process with technical limitations, on the one hand, and the area of existence of the parameters of turning wear-resistant cast iron with a tool made of superhard polycrystalline materials, reflecting the technical and economic indicators of the process, on the other. The methods. In the work, the structural-static dependence of the probability of non-destruction of the tool (composite) is proposed, which is a component of the mathematical model for calculating the parameters of the turning process. Findings. The most characteristic failures of blades from the point of view of the operational reliability of cutting tools are extreme wear as a result of natural wear (gradual failure) and destruction (painting) of the cutting edge as a result of the manifestation of hidden defects of the tool material or exceeding permissible loads and loss of fatigue strength during wear). According to these failure criteria, the initial indicators of the durability and failure-freeness of cutting tools in the theory of cutting and the system of operation of cutting tools are the period of stability. The efficiency of high-strength cast iron turning is inextricably linked to the wear resistance and strength of the tool materials used. The prospect of expanding the use of polycrystalline materials, taking into account boron nitride (composites), emerges from the comparison of the main performance indicators of tool materials. The analysis and experience of using ultra-hard polycrystalline materials showed that with the same cutting depth, lower feed, and high cutting speed, composites provide the largest volume work. The originality. The paper establishes the dependence of the parameters of the cutting tool made of superhard materials on the main parameters of the turning process of cast iron. With the use of grapho-analytical analysis, the primary influence of cutting depth on the period of stability and reliability of trouble-free operation of cutting plates made of superhard materials is substantiated. Practical implementation. It was established that when turning cast iron, wear occurs on both the back and front surfaces of the blade. The reason for the wear of the front surface is the presence of a large amount of wear-resistant chromium carbides and the higher hardness of the chips coming off.

High-temperature tribological performance of stir-cast and heat-treated EV31A magnesium alloy: Experiments and predictions

The temperature effect on the wear behaviour of EV31A Mg alloy during dry sliding wear was investigated. Wear tests were carried out at 50, 100, 150, 200, and 250 °C using a standard load of 10 N and a sliding distance of 1000 m. Weight loss method was used to calculate the wear rate. Optical microscopy was used to examine the microstructure of the EV31A alloy. FE-SEM with EDS analysis was used to investigate the wear morphology, and XRD analysis was performed both before and after the wear test. A high wear coefficient (K) value (more than 10−4) indicates extreme wear for EV31A in all the scenarios. T4 EV31A had a maximum wear rate of 20.2 mg at 150 °C. The as-cast EV31A alloy exhibits an excellent wear rate at the price of mechanical properties under all test scenarios. Wear resistance is improved by Nd and Zr oxides, although Mg and Gd oxides have little effect. Zn has no effect on the wear behaviour of the EV31A. In as-cast, T4, and T6 heat-treated conditions, the EV31A alloy exhibits delamination (abrasive wear), oxide development (corrosive wear), and delamination mixed with plastic deformation (adhesive wear). A Three-layered ANN and adapted Fine Gaussian SVM predicted tribological characteristics. In ANN prediction, the maximum R2 was 0.99 for CoF and 0.89 for wear rate, respectively. Despite the fact that the study's normal load is constant, machine learning models allow to deduce that temperature and normal load are the main influential parameters in CoF and wear rate, respectively.

The mechanical failure of locally manufactured prosthetic feet from the Jaffna Jaipur Centre for Disability Rehabilitation (JJCDR), Sri Lanka.

The International Organization for Standardization (ISO) 10328 standards are used to verify the safety of lower limb prosthetic devices. However, the ISO 10328 tests are performed in sterile laboratory settings and do not account for environmental or sociocultural factors associated with prosthetic use. Most locally manufactured prosthetic feet from low-income and middle-income countries, which are safely used for years, do not meet these standards. In this study, we investigate the modes of wear patterns of naturally worn prosthetic feet from Sri Lanka. To characterize wear patterns of locally manufactured prosthetic feet from low-income and middle-income countries. Sixty-six replaced prosthetic feet from the Jaffna Jaipur Center of Disability and Rehabilitation were analyzed. Delamination between the keel and rest of the foot could not be detected with ultrasound. Sole wear pattern was quantified by photographing soles and dividing them into 200 rectangles and scoring the rectangle's wear from 1 to 9 (no to extreme wear). Homologous scores were averaged to create a contour map of prosthetic foot wear. The highest levels of wear occurred at the heel, end of the keel, and the perimeter of the prosthetic foot. All regions of the prosthetic feet had significantly different wear scores ( p < 0.005). Locally manufactured solid ankle cushion heel feet display high levels of wear in localized areas of the sole of prosthetic feet, which can limit their life span. High levels of wear occur at the end of the keel, which would not be detectable in the ISO 10328 tests.

Tribocorrosive Aspects of Tungsten Carbide, Silicon Nitride, and Martensitic Steel under Fretting-like Conditions

Water-based lubrication faces the common challenge of component lifetime extension which is impaired by tribocorrosion due to material surface depassivation. However, such mechanisms in a pH-neutral and low-halide electrolyte require additional understanding. A ball-on-flat configuration study of hard-phase materials in a low amplitude–high frequency sliding contact against martensitic chromium steel with contact pressures around 200 MPa is presented. Under lubrication by purified water, tungsten carbide-based metal matrix composite (MMC) with NiCr binder and silicon nitride-based ceramic (SiAlON) against DIN/EN 1.4108 steel yielded coefficients of friction above unity. Wear scar enlargement led to fretting-like conditions with adhesion becoming the fundamental wear mechanism. A tribocorrosion-induced depletion of tungsten carbide and nickel was determined for MMC. SiAlON materials suffered extreme wear under the formation of abrasive SiO2, while heat-treated DIN/EN 1.4125 steel showed lower friction and wear, but also showed signs of hydrogen embrittlement. Results from accompanying single-material corrosion experiments could not satisfactorily explain the phenomena. Including galvanic interaction and the influence of contact geometry, a new tribocorrosion model for fretting conditions is proposed. It describes an expanding anodic belt located at the inner-most crevice position of an otherwise cathodically polarized material. Low conductivity of the electrolyte is seen as a key player in this process, while the galvanic situation between two materials in contact was shown to invert when water was substituted by a wet organic phase.

Electronic Properties of Functionalized Diamanes for Field-Emission Displays.

Ultrathin diamond films, or diamanes, are promising quasi-2D materials that are characterized by high stiffness, extreme wear resistance, high thermal conductivity, and chemical stability. Surface functionalization of multilayer graphene with different stackings of layers could be an interesting opportunity to induce proper electronic properties into diamanes. Combination of these electronic properties together with extraordinary mechanical ones will lead to their applications as field-emission displays substituting original devices with light-emitting diodes or organic light-emitting diodes. In the present study, we focus on the electronic properties of fluorinated and hydrogenated diamanes with (111), (110), (0001), (101̅0), and (2̅110) crystallographic orientations of surfaces of various thicknesses by using first-principles calculations and Bader analysis of electron density. We see that fluorine induces an occupied surface electronic state, while hydrogen modifies the occupied bulk state and also induces unoccupied surface states. Furthermore, a lower number of layers is necessary for hydrogenated diamanes to achieve the convergence of the work function in comparison with fluorinated diamanes, with the exception of fluorinated (110) and (2̅110) films that achieve rapid convergence and have the same behavior as other hydrogenated surfaces. This induces a modification of the work function with an increase of the number of layers that makes hydrogenated (2̅110) diamanes the most suitable surface for field-emission displays, better than the fluorinated counterparts. In addition, a quasi-quantitative descriptor of surface dipole moment based on the Tantardini-Oganov electronegativity scale is introduced as the average of bond dipole moments between the surface atoms. This new fundamental descriptor is capable of predicting a priori the bond dipole moment and may be considered as a new useful feature for crystal structure prediction based on artificial intelligence.

Elastic properties of the non-mixing copper donor assisted material in friction stir welding of aluminum alloys using nanoindentation

Friction stir welding of high-strength materials such as steels is the impeded by the lack of the vast heat input needed to start the process. Contact friction is considered the most dominant source of heat generation for FSW steels which tends to cause severe wear conditions of the tool hear. To relieve the extreme wear conditions that occur on the tool heads because of FSW steels, we introduce the non-mixing Cu donor stir material to friction stir welding of aluminum alloys. The elastic properties of the Cu donor assisted friction stir welded aluminum alloys are measured using nanoindentation. The hardness and elastic modulus were measured for two regions, the base metal (BM) and the stir zone (SZ). The measurements were conducted for 20% and 60% Cu non-heat treated (NHT) and heat-treated (HT) samples. The nanomechanical properties were measured using nanoindentation with the continuous stiffness method (CSM) in depth control. The HT samples are softer than the NHT samples as expected. However, the 20% Cu NHT and HT samples depicted the same hardness at the SZ. Similar results were observed for the 60% Cu donor stir samples. It therefore concluded that the SZ is softer than the BM for the 20% and 60% Cu donor stir material as expected. The hardness of the weld at the SZ is similar to the hardness of the Al6061-T6 plate, suggesting that the Cu donor stir material did not impact the hardness properties of the Al6061-T6 plate due to the depletion of the Cu donor stir material during the welding process, an important result of the concept of the donor material. The elastic moduli of the Cu donor stir welded samples vary between 75~85 GPa at a depth of indentation of ~4600 nm, which are different from the elastic moduli of Cu 110 (117.2 GPa) and similar to the elastic modulus of aluminum alloys (68.9 GPa), an important outcome.

Microstructurally driven self-sharpening mechanism in beaver incisor enamel facilitates their capacity to fell trees.

Beavers (Castor) stand out among mammals for their unique capacity to fell trees using their large, ever-growing incisors. This routine consumption of resistant fodder induces prodigious wear in the lower incisors, despite this blunting effect the incisors maintain a remarkably sharp cutting edge. Notably, the enamel edges of their incisors show a highly complex two-part microstructure of which the biomechanical import is unknown. Here, using fracture analysis, nanoindentation, and wear testing on North American beaver (C. canadensis) incisors we test the microstructure's possible contribution to maintaining incisal sharpness. Although comparable in hardness, the inner enamel preferentially fails and readily wears at 2.5 times the rate of the outer enamel. The outer microstructure redirects all fractures in parallel, decreasing fracture coalescence. Conversely, the inner microstructure facilitates crack coalescence increasing the wear rate by isolating layers of enamel prisms that readily fragment. Together these two architectures form a microstructurally driven self-sharpening mechanism contained entirely within the thin enamel shell. Our results demonstrate that enamel microstructures exposed at the occlusal surface can markedly influence both enamel crest shape and surface texture in wearing dentitions. The methods introduced here open the door to exploring the biomechanical functionality and evolution of enamel microstructures throughout Mammalia. STATEMENT OF SIGNIFICANCE: Enamel microstructure varies significantly with the diversity of diets, bite forces, and tooth shapes exhibited by mammals. However, minimal micromechanical exploration of microstructures outside of humans, leaves our understanding of biomechanical functions in a nascent stage. Using biologically informed mechanical testing, we demonstrate that the complex two-part microstructure that comprises the cutting edge of beaver incisors facilitates self-sharpening of the enamel edge. This previously unrecognized mechanism provides critical maintenance to the shape of the incisal edge ensuring continued functionality despite extreme wear incurred during feeding. More broadly, we show how the architecture of prisms and the surrounding interprismatic matrix dictate the propagation of fractures through enamel fabrics and how the pairing of enamel fabrics can result in biologically advantageous functions.

Effect of Subcritical Treatment (Tempering) on Hardness and Wear of High Chromium White Cast Iron

High chromium white cast iron (HCWCI) is used in mining, crushing plants, as mill liners, and in the manufacture of grinding balls. The grinding ball is the essential element in fine fragmentation. It must have an excellent life to counter extreme wear and impact conditions that it undergoes. Hence it is important to improve its mechanical properties. This study aims to find the effect of tempering temperature on microstructure, hardness, and abrasive wear of High Chromium White Cast Iron used in the manufacture of grinding balls. In this study, the balls in high chromium white cast iron with 12 to 17% Cr, of 50mm and 70mm in diameter were austenitized at 950°C for 45 min and 55 min for the balls of 50 and 70mm then were quenched in forced air. The balls were tempered at 250°C, 400°C, and 600°C for 120 min and 180 min for both diameters 50 and 70mm respectively, and cooled in the furnace. The results showed that tempering practiced at 250°C and 400°C gives an excellent hardness than balls austenitized at 950°C. It is about 60 HRC and it drops to less than 50 HRC for the tempering at 600°C. This tempering causes a significant mass loss (short life) but tempering at 250°C and 400°C decreases this loss by up to 1.6%. The results of XRD showed the presence of the martensite and carbides type M7C3 after tempering at 250°C and a ferritic matrix after tempering at 600°C.

Optimization of material and process parameters for plasma transferred arc hard facing for high temperature applications

The authors in this research paper have investigated the process of hardfacing, which is a well-established manufacturing process for increasing the durability of industrial components, which are subjected to extreme wear, erosion, abrasion. The objective of this study is to establish a scientific methodology to select the most suitable combinations of materials as base-deposition materials for hardfacing, specifically focusing on Nickel-based and Cobalt-based materials. In order to make an informed decision, multi-criteria decision-making method known as “Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS)” is used. This technique permits to deal with wide range of important factors, such as the materials' high-temperature resistance, wear resistance, and corrosion resistance, among others. The paper discusses a step-by-step approach to selecting the best alternative material for hardfacing by considering eight different criteria and assigning preferences to each of the available materials. The results of this methodology suggested that Stellite-6 based cobalt-based alloy is best suitable for AISI 304 grade austenitic stainless steel materials used for high temperature applications.In addition, the paper also studies the effects of various welding parameters on the hardfacing process. This includes parameters such as welding current, welding speed, powder feed rate and the type of shielding gas used. The significance of each parameter is also studied, and the results of these investigations are discussed in detail. Overall, this research paper provides a comprehensive overview of the hardfacing process and the materials and techniques that are best suited for it, making it valuable resource for professionals and researchers in the field.

WEAR CHARACTERISTICS OF 3D PRINTED PLASTIC GEAR WITH DIFFERENT INFILL PERCENTAGES

Polymer gears have great potential in motion and power transmission since they offer many advantages over conventional metal gears. However, the use of polymer gears in industrial applications has been limited due to inadequate information with respect to their performance and designs. In this research work, our goal was to study and analyze the characteristics of a polymer gear produced from polylactic acid through the a three-dimensional (3D) printing process. Experiments involving polymer test gears were carried out on a test rig at three rotational speeds. The parameters studied during the investigation were the infill percentage, rotational speed, and load attendance. Four types of failure characteristics-namely, the formation of debris, micro-surface condition monitoring, weight loss, and thermal damage-were analyzed in the experiments. The investigation showed that the weight reduction wear rate was related to the development of debris and the condition of the gear. The test gear wear rate from the weight reduction through material scratching and breakage increased progressively under extreme wear conditions. Further thermal analysis and microstructure observations also revealed the impact of temperature from frictional heat on the amount of wear on the polymer gear. The higher the operating temperature, the higher was the amount of wear seen in the polymer gear.

A Wear Sensor Based on Nanocrystalline Diamond Multilayer Films: A Mini Review

Major amounts of industrial wear parts, e.g. machining tools, are working under extreme wear load, especially abrasive. This short article reviews the development and fabrication of a well-performing nanodiamond-based multilayer wear sensor system consisting of alternating conductive and non-conductive films. Meanwhile, the deposition and characterization of such highly conductive nanocrystalline diamond films without dopant are also introduced.

Wear resistance effects of alumina and carbon nanoscale fillers in PFA, FEP, and HDPE polymers

Following numerous studies demonstrating the ability of nanostructured alpha-alumina filler to reduce the prohibitively high wear rate of polytetrafluoroethylene (PTFE) down to extremely small values (∼10−7 mm3/Nm) well below those of conventional PTFE micro-composites, alpha-alumina filler was also shown capable, in a couple recent studies, of imparting similar performance to another fluoropolymer, perfluoroalkoxy (PFA) copolymer, which otherwise was similarly lacking wear resistance in the unfilled state. In addition to duplicating such alpha-alumina performance in PFA, in this study such an extreme wear-reducing capability has also been demonstrated using nanocarbon powder, as an example representative of several other forms of nanoscale carbon filler that like alpha-alumina had been shown capable of providing extreme resistance to PTFE. Fluorinated ethylene propylene (FEP) copolymer, whose nanocomposites have not been tribologically explored previously, was thus more fully investigated here with not only alpha-alumina and nanocarbon, but also other nanotube (CNT) and mesoporous forms of nanoscale carbon fillers. In preliminary testing, only the alpha-alumina filler indicated an ability to impart its wear-reducing capability to FEP; a wear rate of ∼0.8 × 10−6 mm3/Nm was observed at 2 wt% alpha-alumina concentration. While this is an impressive reduction in wear rate, it is not quite as extreme a reduction as that observed in PTFE or PFA. The transport of the extreme wear resistance of nanocarbon powder in PTFE and PFA was even more partial and incomplete in FEP, with the ∼0.3 × 10−3 mm3/Nm unfilled FEP wear rate only reduced to ∼10−5 mm3/Nm, while the CNT and mesoporous carbon fillers were even less effective. Correspondingly, ATR-FTIR spectra from FEP wear surfaces displayed sizable peaks evident of the chelation of chemical interactions known to be associated with wear resistance for PTFE and PFA matrices only in the most wear-resistant alpha-alumina case and to a lesser extent for the nanocarbon. Finally, it is demonstrated that such fillers demonstrate such strongly beneficial effects only in polymers that otherwise lack wear resistance, and may actually be deleterious for polymers such as high density polyethylene (HDPE) already having some inherent wear resistance in their unfilled state.

A hydroponic system for natural turf that can take extreme wear as an alternative to artificial grass surfaces

AbstractNatural grass areas in high‐traffic and stress locations are being converted into artificial grass by inconsistent moisture conditions in root‐zone and poor grass conditions. As an alternative solution to this method, natural grass was planted instead in a washed sand without organic matter and with a constantly moving water table and no overhead irrigation. Water consumption and surface quality after heavy machinery exposure was measured. A significantly increase in the potential for traffic and play was observed, along with water savings of up to 85% compared with normal overhead irrigation amounts for similar surfaces (golf course tees).

Tribomechanical and microstructural properties of cathodic arc-deposited ternary nitride coatings

Sintered carbides are promising materials for surfaces that are exposed to extreme wear. Owing to their high service load, ceramic-based thin films are coated on carbides using different techniques. In this study, non-toxic and cobalt-free powder metallurgy-sintered carbide samples were coated with TiN, TiAlN, CrAlN, and TiSiN ceramic-based thin film coatings by cathodic arc physical vapor deposition. The microstructure (phase formation, coating thickness, surface roughness, and topography), mechanical properties (hardness, modulus of elasticity, and plasticity indices), and tribological properties (nanoscratch and wear behavior) of the thin film coatings were investigated. No cracks or defects were detected in these layers. The ceramic-based ternary nitride thin film coatings exhibited better mechanical performance than the TiN coating. The TiN thin film coating had the highest average surface roughness, which deteriorated its tribological performance. The ternary nitride thin film coatings exhibited high toughness, while the TiN thin film coating exhibited brittle behavior under applied loads when subjected to nanoscratch tests. The wear resistance of the ternary nitride coatings increased by nearly 9–17 times as compared to that of the TiN coating and substrate. Among all the samples investigated, the substrate showed the highest coefficient of friction (COF), while the TiSiN coating exhibited the lowest COF. The TiSiN thin film coating showed improved mechanical and tribological properties as compared to other binary and ternary nitride thin film coatings.

Resistance to slurry erosion by WC-10Co-4Cr and Cr3C2 − 25(Ni20Cr) coatings deposited by HVOF stainless steel F6NM

Hydroelectric turbine machinery experience extreme wear and tear due to slurry erosion and is one of the leading causes for the unplanned shutdown of hydro power plants. The coatings produced by High-velocity oxy-fuel (HVOF) thermal spray process on different hydro-turbine parts is known for improving wear resistance. In the present study, WC-10Co-4Cr and Cr3C2 − 25(Ni20Cr) coatings were sprayed by HVOF process on F6NM stainless steel of Dul-Hasti hydro-power plant turbine material. The slurry erosive wear studies of developed coatings was performed using high speed slurry erosive wear tester. Sediments collected from Dul-Hasti power plant dam site was taken as erodent material. The effect of four parameters specifically rotational speed (500–1250 rpm), slurry concentration (25–40 wt%), sand particle size (125–425 μm), and test duration (450–900 min) on slurry erosion of coated materials was studied. It was observed that among all the developed three coatings, the WC-10Co-4Cr coated samples has shown superior erosion resistance compared to Cr3C2 − 25(Ni20Cr) coated samples due to its improved micro-hardness. Both the developed coatings were observed to be useful in enhancing the erosion resistance of F6NM steel significantly. Erosion mechanism were studied in detail using SEM. The properties such as hardness and porosity were also examined.