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The purpose of this work was to determine the essence of the influence of the impact velocity (5, 7, and 9 m/s) on Hertzian stresses and the erosion mechanism of ferritic-pearlitic S355J2 steel. The investigations were carried out using a slurry pot tester. S355J2 steel showed a strong sensitivity to changes in impact velocity. A significant increase in erosion rate was observed at a velocity of 9 m/s. This increase was 5-fold and over 15-fold compared to velocities of 7 m/s and 5 m/s, respectively. The study of Hertzian stress is crucial in erosion research because it helps understand how impact energy is absorbed by the eroded material and the mechanisms that cause surface wear. A linear increase in mean contact pressure and maximum shear stress was observed with increasing impact velocity. The mean contact pressure increased from 4.3 GPa to 5.5 GPa and the maximum shear stress increased from 2.0 GPa to 2.5 GPa. The kinetic energy of the solid particles that hits the eroded steel is distributed in the contact area, which leads to various deformations and wear mechanisms. The primary type of deformation was fatigue degradation of the surface layers of the eroded steel. The high kinetic energy of solid particles contributed to the formation of plastic deformations and strongly deformed steel flakes. Higher impact velocities generally result in greater forces and contact stresses on the material surface. This led to the intensification of plastic deformation in the contact areas and increased the Hertzian stresses. [ABSTRACT FROM AUTHOR]

Slurry erosion is the surface degradation process occurring due to the mechanical interactions between the solid surface and the particles in the presence of a fluid medium. Due to the slurry erosion, machinery components in the industrial fields (like the hydraulic turbines, slurry pipelines, etc.) conditions undergo severe damage such that the machine parts couldn't be repaired and should be replaced with the new ones sooner. The present research work described a slurry jet erosion test rig based on the modified venturi devices. Slurry erosion tests were conducted by varying the parameters such as the impingement angle, velocity, concentration, silica sand as the erosive particles with size, and with cast iron as the test coupon. Artificial neural network methodology based on machine learning and artificial intelligence was adopted to identify the dominating parameter among the chosen test parameters. The experimental and the artificial neural networks method results confirmed that the impingement angle was the most significant parameter for causing the material removal amongst the other parameters. Specifically, from the artificial neural network prediction, it was found that the contribution of parameters for erosion prediction was impingement angle (highest) > velocity > concentration > erosive particle size (lowest). It was also reported that with an increase in the velocity the erosion of the test coupon also increased. This investigation may help the materials scientists to accelerate their studies on cast iron material domain. [ABSTRACT FROM AUTHOR]

In recent years, protective coatings have become crucial in graphene‐based chemical studies. This research investigates the anticorrosive properties of coatings created by co‐depositing carbon compounds. Electroless Ni−P‐PAA@F‐GO coatings were applied to stainless steel by adding various amounts of PAA@F‐GO particles to the Ni−P bath. The coated samples were analyzed using X‐ray diffraction and micro‐hardness tests, revealing a peak hardness of 764 HV at 30 mg/L PAA@F‐GO, compared to 521 HV for standard Ni−P coatings. Corrosion performance was evaluated in a 3 % sodium chloride solution, showing that despite a higher corrosion‐erosion rate. Although the coated samples exhibited a corrosion‐erosion rate 4.7 times higher than untreated samples, the mass loss was notably more pronounced in the untreated samples. The study found that adding PAA@F‐GO particles improved corrosion resistance and durability, with optimal results at a specific particle concentration. The enhanced performance is attributed to the increased roughness, impermeability, and hydrophobicity of the functionalized graphene oxide. [ABSTRACT FROM AUTHOR]

Nowadays, computational and computing tools are widely used in prediction applications. Neural computing is a modern and emerging technique to predict data efficiently and precisely. In this context, erosion investigation of Mo2C–WC10Co4Cr high-velocity oxy-fuel (HVOF) deposited on AISI 316L was carried out in the present work by implementing a neural computing and Taguchi's method. This research paper focuses on neural network (NN) technique for the prediction of erosion in Mo2C–WC10Co4Cr HVOF coating. The WC10Co4Cr powder was composed of 3% (by weight) of molybdenum carbide, each with a concentration of 3 wt.%. The input parameters used for designing the NN model were erodent properties (bulk density, circularity factor, average particle size, and slurry concentration), material properties (hardness and porosity of bare/coated), and process parameters (speed and time). A set of experiments was optimised by using Taguchi's method (L16 2 × 5 array). Results indicated that the overall accuracy of Pearson coefficient (R) was found as 0.99582 with experimental data. However, R = 1 was found for testing results. [ABSTRACT FROM AUTHOR]

The purpose of this work was to determine the essence of the influence of the impact velocity (5, 7, and 9 m/s) on Hertzian stresses and the erosion mechanism of ferritic-pearlitic S355J2 steel. The investigations were carried out using a slurry pot tester. S355J2 steel showed a strong sensitivity to changes in impact velocity. A significant increase in erosion rate was observed at a velocity of 9 m/s. This increase was 5-fold and over 15-fold compared to velocities of 7 m/s and 5 m/s, respectively. The study of Hertzian stress is crucial in erosion research because it helps understand how impact energy is absorbed by the eroded material and the mechanisms that cause surface wear. A linear increase in mean contact pressure and maximum shear stress was observed with increasing impact velocity. The mean contact pressure increased from 4.3 GPa to 5.5 GPa and the maximum shear stress increased from 2.0 GPa to 2.5 GPa. The kinetic energy of the solid particles that hits the eroded steel is distributed in the contact area, which leads to various deformations and wear mechanisms. The primary type of deformation was fatigue degradation of the surface layers of the eroded steel. The high kinetic energy of solid particles contributed to the formation of plastic deformations and strongly deformed steel flakes. Higher impact velocities generally result in greater forces and contact stresses on the material surface. This led to the intensification of plastic deformation in the contact areas and increased the Hertzian stresses.

Slurry erosion testing is essential for evaluating the durability of materials under erosive conditions. This study examines the slurry erosion behaviours of chloroprene rubber (CR) under varying impact conditions to assess its durability. Traditional mass loss methods and qualitative techniques, including microscopy, SEM, and AFM, were employed to analyse eroded CR samples. Results indicate that cumulative material loss in CR increases linearly with sand impingement after approximately 60 kg of sand and correlates with an impact energy of about 30 kJ. The highest erosion rate was found at an impact angle of 15°. Erosion mechanisms vary with impact angle, affecting surface topography from cutting and ploughing at lower angles to deformation and crater formation at higher angles. Despite their efficacy, these methods are time-intensive and costly. This paper presents a novel approach utilising gloss measurement for continuous, non-destructive monitoring of eroded rubber surfaces. Gloss measurements are 24 times faster than traditional mass loss methods. Correlating gloss values with cumulative material loss, steady-state erosion, and impact energy offers significant time savings and an enhanced understanding of the erosion process. Experimental results demonstrate the effectiveness of gloss measurement as a reliable tool in slurry erosion testing of rubbers. The quantitative output from gloss measurements could support proactive maintenance strategies to extend service life and optimise operational efficiency in industrial applications, particularly in the mining industry. [ABSTRACT FROM AUTHOR]

In the current investigation, a cold sprayed WC-12Co (WC- Tungsten Carbide, Co- Cobalt) composite coating was deposited on CA6NM steel. Further, microstructural analysis was carried out by using Scanning Electron Microscopy (SEM)/Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD) characterization techniques. Mechanical characterization was carried out to measure microhardness, bond strength and surface roughness. The value of coating hardness and surface roughness was measured to be 270 ± 15 Hv and 2.12 ± 0.5 μ m. Thereafter, slurry erosion test was performed under accelerated conditions and performance of coated samples was compared under different parameters such as erodent size, impact velocity, angle of impingement and slurry concentration. WC-12Co coatings show no phase transformation or de-carburization of the WC-Co particles as observed in other thermal spray techniques. The WC-12Co coatings was proved to have beneficial erosion reduction rate as compared to untreated CA6NM steel. The slurry erosion performance of coated samples was improved by 68%. SEM images of degraded coatings show the brittle characteristic of WC-12Co coatings. [ABSTRACT FROM AUTHOR]

This work presents a novel insight into slurry erosion behavior of thin layer of carbon fiber–epoxy-based composite adhered on 16Cr5Ni steel (adhesive coating) to evaluate its viability as a feasible candidate for slurry erosion applications. Experiments were conducted on a laboratory-developed slurry erosion test rig under accelerated conditions to study the effect erosion parameters namely slurry concentration, impact angle, and impact velocity. Under all the experimental conditions, adhesive coating showed better slurry erosion resistance in comparison with bare 16Cr5Ni steel specimens. Scanning electron microscopy analysis revealed that in the case of bare 16Cr5Ni steel; ploughing, micro-cutting, crater, plastic deformation, and lip formation were identified as main mechanism responsible for slurry erosion, whereas in the case of adhesive coating; pitting, cracking, fracturing, and shearing-off were found to be mainly responsible for material loss. It implies that adhesive coating showed a brittle mode of failure under slurry erosion conditions, whereas 16Cr5Ni steel exhibited a ductile mode of erosion. [ABSTRACT FROM AUTHOR]

One of the biggest problems the maritime industries confront is the erosion of composite structures brought on by interaction with sludge and sea debris. In the current study, erosion behaviour of cenosphere reinforced syntactic foam is examined in relation to specimen rotation angle, slurry concentration, and rotational speed. Moulding method was used to create the specimens. Sea sand particles were used as the erodent material in experiments carried out in a slurry pot erosion test rig. The impact of particular parameters on erosion is examined using the Taguchi L9 array. A scanning electron microscope was used to analyse the morphology of the eroded surfaces in order to analyse the erosion behaviour. Maximum erosion was seen when the Cenosphere content is least in the syntactic foams and the erosion process may be classified as semi-ductile in nature. It has been found that Cenosphere content have a major impact on erosion behaviour. The erosion damage in the matrix diminishes as the volume % of cenospheres rises, indicating that cenospheres boost the material's resistance against erosion.

The purpose of this research was to investigate the cause of a slurry erosion failure in an Al2O3-13TiO2 high-velocity oxygen-fuel coating for SS316L steel. Sand particles served as the erodent in this investigation of wear and erosion. The slurry erosion of SS and HVOF Al2O3-13TiO2 coating was shown to be significantly affected by speed of particles, concentration (wt%), and exposure period. All characteristics, excluding impingement angle, contribute to faster wear on the parent material, both bare and coated AISI 316 L. Coatings were used to slow down the pace at which the source material deteriorated. As a whole, the Al2O3-13TiO2 HVOF coating enhanced the AISI 316 L's resistance to erosion by 13.73%. [ABSTRACT FROM AUTHOR]

The slurry erosion processes of horizontal elbows are investigated numerically using an Eulerian-Lagrangian method coupled with particle rebound and erosion model. First, a mechanical model for the internal multiphase flow involving slurry erosion in the 90° horizontal elbow is established and the corresponding governing equations are presented. Then, a two-way coupled numerical solution procedure is developed and its accuracy and stability are examined carefully using benchmark pipe flow models with experimental results. Using the validated numerical methods, the effects of flow velocity, fluid density and fluid viscosity on the flow and slurry erosion in the horizontal elbow are analyzed in detail. Finally, a prediction method of erosion rate distribution based on the pipe Froude number, particle Stokes number and the Dean number is proposed. In this method the pipe Froude number is employed to qualify the effect of ununiform distribution of particles, particle Stokes number and Dean number are combined to qualify the effects of inertia force, drag force and secondary flow. Using this approach, the location of the maximum erosion rate in horizontal elbows under different operating conditions can be predicted more conveniently. [ABSTRACT FROM AUTHOR]

Iron-based alloys which pose better strength and good mechanical properties as compared to other metal alloys find their application in many sectors. This paper focuses on the impact of parameters of three different compositions Fe43Mn15Cr12Ni10B7WC13, Fe43Mn15Cr12Ni10B11WC9 and Fe43Mn15Cr12Ni10B15WC5on coated SS316L substrate. Four parameters impact velocity, impingement angle, sand particle feed rate and sand particle size are selected for the L16 orthogonal array to optimize the erosion wear rate. The erosion rate is predicted using an artificial neural network (ANN). The impact velocity and sand particle feed rate are found to have a major role in erosion rate. In this study, the Taguchi method applied that give the optimum parameter for all three compositions being used in the present work. For the first composition, the optimal parameters are velocity 10 m/sec, angle 30°, sand particle feed rate 160 gm/min and particle size 195 µm. For composition Fe43Mn15Cr12Ni10B11WC9, the optimum parameter is having velocity 10 m/sec, angle 75°, sand particle feed rate 265 gm/min and particle size 375 µm and for composition Fe43Mn15Cr12Ni10B15WC5, the optimized parameters are having velocity 40 m/s, angle 75°, sand particle feed rate 160 gm/min and sand particle size 300 µm. ANN anticipates the erosion rate with 93% accuracy. [ABSTRACT FROM AUTHOR]

One of the biggest problems the maritime industries confront is the erosion of composite structures brought on by interaction with sludge and sea debris. In the current study, erosion behaviour of cenosphere reinforced syntactic foam is examined in relation to specimen rotation angle, slurry concentration, and rotational speed. Moulding method was used to create the specimens. Sea sand particles were used as the erodent material in experiments carried out in a slurry pot erosion test rig. The impact of particular parameters on erosion is examined using the Taguchi L9 array. A scanning electron microscope was used to analyse the morphology of the eroded surfaces in order to analyse the erosion behaviour. Maximum erosion was seen when the Cenosphere content is least in the syntactic foams and the erosion process may be classified as semi-ductile in nature. It has been found that Cenosphere content have a major impact on erosion behaviour. The erosion damage in the matrix diminishes as the volume % of cenospheres rises, indicating that cenospheres boost the material's resistance against erosion. [ABSTRACT FROM AUTHOR]

Erosion is a phenomenon and is the primary cause of failure in numerous slurry transportation equipment such as pump impellers, pipeline fittings, etc. It reduces the working life of the equipment and is thus an essential factor in the design, choice, and operation of any system. Pipeline materials used to convey slurry often experience severe wear from erosive forces. Researchers are interested in minimizing erosion wear using different coatings to increase equipment life. The High-Velocity Oxy-Fuel (HVOF) spray technique was employed to deposit WC-10Co-4cr + 2% TiO2 coating on the SS409. The erosion wear was evaluated using a slurry jet erosion tester of uncoated and coated materials with sand as the erodent. The impact of impingement angle, velocity, time, and other parameters was studied. On the erosion wear of uncoated and coated materials, it was found that the influence of jet velocity was greater than the impact of other parameters. The deteriorated surfaces were analyzed using a scanning electron microscope (SEM). The erosion wear resistance of SS 409 was significantly improved by the WC-10Co-4cr + 2% TiO2 coating. The coating demonstrated a brittle mechanism of erosion wear. Furthermore, image processing software investigated the mechanism of erosion wear.

The present study deals with the erosive wear behaviour of a zinc-aluminum (ZA) alloy and composite in the slurry medium. The effects of reinforcement of zirconium diboride (ZrB2) particles in ZA alloy, as well as the impingement angle and duration of erosion wear responses have been studied. The slurry composition was prepared with 1.5 L of water and 500 g silica of a size range of 350–450 μm. The erosion tests are performed at a speed of 600 rpm for varying durations (20–80 h) and impingement angles (30°–90°). The erosive wear responses of the samples have been analyzed in terms of distinct features of their micro constituents like ZrB2 and the material removal mechanism in a prescribed set of conditions. A significant decrease in composite erosion compared to ZA alloy has been observed. With increased duration, both alloy and composite show increased erosive wear. Obtained results revealed that the composite shows 60–80 % less erosive wear than ZA alloy on operating conditions. The optimum results in wear have been observed at 45° for alloy and 60° for composite. Investigating topographical aspects using scanning electron microscopy and atomic force microscopy revealed that ZrB2 reinforcements resulted in smoother topography and reduced erosive wear.

Understanding slurry erosion characteristics in a fit clearance structure is vitally important for improving the service life of downhole tools. In this study, erosion test equipment was designed to simulate the flow of high-speed drilling fluid in a clearance, and its performance was tested by studying the concentration effect of solid particles on the erosion behavior of a commonly used 38CrMoAlA steel material in downhole tools. The experimental results revealed that localized erosion occurred on the clearance internal surface along the flow channel direction. An area a certain distance from the slurry entry was most severely eroded. Moreover, the erosion rate, erosive wear depth, and surface hardness increased while the roughness of the eroded surface decreased with increasing particle concentration. To extend the service life of downhole tools, the concentration of solid particles should be controlled, and the localized erosive area should be prioritized. [ABSTRACT FROM AUTHOR]

Tool steels are well known to have superior strength and are claimed to have superior wear resistance than conventional steels in several scenarios. However, their behavior under slurry erosion conditions have been seldom studied. To this end, a set of tool steels, primarily from the CPM yV (y = 1, 3, 9, 10, 15) alloy family, was selected to understand the effect of hardness and vanadium carbide content on the slurry jet erosion (SJE) performance at different impingement angles. It was observed that the SJE resistance increases with the increase in the vanadium carbide volume fraction, but is independent of alloy hardness. [ABSTRACT FROM AUTHOR]

In this paper, the performance of hardsurfacing Cobalt alloy (Stellite 6) and Nickel alloy (Colmonoy 88) was tested in tribological slurry conditions by using a pot tester. Thermal spraying powders were deposited on AISI 316L substrates by using a high-velocity oxy-fuel (HVOF) technique. Wear experiments are carried out using a lab-scale pot tester at low velocities like 1.81, 2.71, 3.61, and 4.59 m/s. The high mass flux of ashes (ranging 30–60 wt%) is used to produce severe accelerated conditions. The effect of the size fraction of eroding particles was evaluated by preparing the multi-sized slurries of size fractions (ASTM: −200, −140 + 200, −100 + 140, and −60 + 100). Results show that the microhardness of AISI 316L was improved by the HVOF depositing of Cobalt alloy-6 and Nickel alloy-88. The average surface microhardness of Cobalt alloy-6 was found lower (439 ± 19 HV1000) than the Nickel alloy-88 coating (601 ± 11 HV1000). Erosion performance of coatings was found to be increased with an increase in the value of the velocity, time, mass flux, and weighted mean size of eroding particles. Results show that the Ni-alloy improved the wear resistance of AISI 316L by 2.03 ± 0.021 times in fly ash slurry conditions and 3.21 ± 0.035 times in bottom ash slurry conditions. However, the Co-alloy was beneficial in reducing the wear of AISI 316L by 1.48 ± 0.019 times in fly ash and 2.50 ± 0.032 times in bottom ash slurry conditions. Moreover, the maximum wear of AISI 316L steel was observed at an impingement angle of 30° whereas 60° and 45° for Ni-alloy and Co-alloy coatings respectively in fly ash conditions. Although, the AISI 316L and Ni-alloy coating show maximum wear at the same impingement conditions under the bottom ash slurry conditions. However, the Co-alloy coating showed maximum wear at 60° in bottom ash slurry conditions.

In this paper, AlCoCrFeNi high-entropy alloy composite coatings using the AlCoCrFeNi matrix with Ni-coated-Al2O3 reinforcement were prepared by laser cladding to investigate the effect of Ni-coated-Al2O3 addition on slurry erosion resistance. Microstructure and microhardness of all high-entropy alloy (HEA) composite coatings were characterized by using x-ray diffraction, scanning electron microscope and Vickers hardness measurement. The slurry erosion test was carried out by using an abrasive waterjet method to evaluate the erosion performance of all coatings. The results show that AlCoCrFeNi HEA composite coatings present the typical equiaxed crystal structure with the single body-centered cubic (BCC) phase. After adding the Ni-coated-Al2O3 reinforced powders, the grains of composite coatings are gradually refined with increase in Ni-coated-Al2O3 mass fraction. The average microhardness of composite coatings increases with the increase in the Ni-coated-Al2O3 powder content. The cumulative mass loss of the composite coatings is lower than that of martensitic stainless steel substrate and gradually decreases with the increase in Ni-coated-Al2O3 mass fraction, which proves the addition of Ni-coated-Al2O3 particles can effectively enhance the slurry erosion resistance. Ploughing and micro-cutting are the primary erosion mechanisms of AlCoCrFeNi-x Ni-coated-Al2O3 composite coatings at low erosion angle, while the erosion mechanisms of composite coating material loss are dominated by ploughing and craters at high erosion angle. [ABSTRACT FROM AUTHOR]

The thermal spray coatings are commonly employed in slurry pump components and hydrodynamic turbine blades, where wear progression is an intricate phenomenon. In this research work, the performance analysis of HVOF and APS sprayed WC20Cr3C27Ni coatings for slurry erosion wear is carried out by using artificial neural networks (ANN). The influence of time, particle size, impact angle, speed, and slurry concentration on wear performance of coatings and turbine steel substrate are evaluated. Under the experimental settings, slurry erosion wear rates and mass loss for both coatings and substrate were determined. When ASTM A743 steel was coated with thermal sprayed WC20Cr3C27Ni coatings, the slurry erosion wear resistance of the steel was enhanced by 2 and 3.5 times for APS and HVOF coatings, respectively. The design of ANN made it possible to examine the interactions between the seven input variables. A robust model was formed by the two outputs that followed. This model enables the prediction of slurry erosion wear rate and mass loss of WC20Cr3C27Ni coatings and substrate. [ABSTRACT FROM AUTHOR]

The wear resistance of Ni-Hard alloyed cast iron under slurry erosion is studied. An attempt to predict the erosion wear of materials with the help of an artificial neural network (ANN) is made based on the experimental data on the wear of a slurry pot tester under different operating conditions. The ANN model for predicting the erosion wear of materials is proposed, which has been shown to be highly accurate. The model will allow choosing materials that satisfy the specific performance characteristics without conducting long-term tests under various operating conditions. [ABSTRACT FROM AUTHOR]

In this paper, the performance of hardsurfacing Cobalt alloy (Stellite 6) and Nickel alloy (Colmonoy 88) was tested in tribological slurry conditions by using a pot tester. Thermal spraying powders were deposited on AISI 316L substrates by using a high-velocity oxy-fuel (HVOF) technique. Wear experiments are carried out using a lab-scale pot tester at low velocities like 1.81, 2.71, 3.61, and 4.59 m/s. The high mass flux of ashes (ranging 30–60 wt%) is used to produce severe accelerated conditions. The effect of the size fraction of eroding particles was evaluated by preparing the multi-sized slurries of size fractions (ASTM: −200, −140 + 200, −100 + 140, and −60 + 100). Results show that the microhardness of AISI 316L was improved by the HVOF depositing of Cobalt alloy-6 and Nickel alloy-88. The average surface microhardness of Cobalt alloy-6 was found lower (439 ± 19 HV 1000) than the Nickel alloy-88 coating (601 ± 11 HV 1000). Erosion performance of coatings was found to be increased with an increase in the value of the velocity, time, mass flux, and weighted mean size of eroding particles. Results show that the Ni-alloy improved the wear resistance of AISI 316L by 2.03 ± 0.021 times in fly ash slurry conditions and 3.21 ± 0.035 times in bottom ash slurry conditions. However, the Co-alloy was beneficial in reducing the wear of AISI 316L by 1.48 ± 0.019 times in fly ash and 2.50 ± 0.032 times in bottom ash slurry conditions. Moreover, the maximum wear of AISI 316L steel was observed at an impingement angle of 30° whereas 60° and 45° for Ni-alloy and Co-alloy coatings respectively in fly ash conditions. Although, the AISI 316L and Ni-alloy coating show maximum wear at the same impingement conditions under the bottom ash slurry conditions. However, the Co-alloy coating showed maximum wear at 60° in bottom ash slurry conditions. [ABSTRACT FROM AUTHOR]

The prediction of erosion in WC-10Co4Cr thermal spray coating is predicted using regression machine learning technique. A pot tester helped to examine the erosion rate of WC-10Co4Cr thermal spray coatings. WC-10Co4Cr thermal spray powder was sprayed onto the SS316L steel. Different impingement conditions (30, 45, and 60°) were tested by using textures designed to simulate erosion. The collected data is used to construct a robust Gaussian Process Regression (GPR) model. The projected values are compared to the actual values obtained via experimentation. To further demonstrate the accuracy of the suggested model, the produced model is compared to various state-of-the-art machine learning methods. The GPR outperforms more commonplace methods of other regression techniques like decision trees, Ensemble boosted trees, and linear regression models. The erosion of coated and bare SS316L austenitic steel was effectively predicted using a GPR model.

Varied compositions of TiC (Titanium Carbide) and CuNi-Cr (Cupronickel-Chromium) have been examined as coating materials for hydro machinery steel (SS316) using HVOF spraying system. The slurry erosion experiments have been performed to evaluate these coatings' effectiveness among themselves as well as against bare SS316 steel. In regard to this, the effect of different factors affecting the slurry wear of specimens, such as jet velocity, slurry concentration, and impingement angle have been examined. Further, porosity, microhardness, and surface roughness of the specimens have been measured, and the structure of the developed coatings was also analysed using XRD and SEM. Based on the outcomes of the experiments, it was converged that among the different coatings evaluated, 100% TiC based coating has shown significantly higher resistance to erosion in contrast to other candidate coatings which may be due to higher micro-hardness attribute availed by TiC granules. Moreover, as compared with bare SS316 steel, a substantial augmentation in the slurry wear resistance of SS316 steel was observed as contrasted with all the other developed coatings. Ductile mode of failure was noticed for specimen with CuNi-Cr as primary element, which was found to exhibit brittle mode with the increment in TiC percentage. [ABSTRACT FROM AUTHOR]

In this paper, an investigation was carried out to test the suitability of potential additive materials in WOKA 3533 (WC-10Co4Cr) cermet HVOF coating subjected to slurry erosion in ash conditions. The additives namely molybdenum carbide, yttrium oxide, and zirconium oxide were added in equal percentages (3 wt.%) in WOKA cermet powder. High-velocity oxy-fuel (HVOF) spraying was performed to develop the additive-based WOKA cermet coatings. The slurry erosion in ash conditions was tested using the pot tester. Microstructural and mechanical properties of traditional and additive-based WOKA cermet coatings were also tested in the present study; for example, microstructure, crystalline phases of as-sprayed coatings, and microhardness. Results present a comparison of surface erosion wear of different cermet coatings. It was found that the yttrium oxide was a suitable additive for the WOKA cermet coatings than the molybdenum carbide. However, zirconium oxide is unsuitable for WOKA cermet coatings in erosion wear applications.

To increase the erosion resistance of 2024 Al alloys, plasma nitriding surface treatment was used. Nitrogen and argon gases are injected into an evacuated chamber until the pressure reaches 15 Pa. The process requirements for normal plasma nitriding were heating at 440˚C for 8 hours, low voltage of 650 V, current of 25 mA, low gas consumption, and no air pollution. A continuous nitriding layer of AlN was formed. The microhardness reached a maximum value of 170 HV, about 3 times higher than that Al melts at, is transported upward through voids and capillaries in the AlN structures, and reacted with N plasma in the melt surface. The growth of the AlN structures promotes this transport of un-nitride alloy subjected to the same heat treatments. As a result, the erosion rate of the nitrided samples decreased by 10% when compared to the ones that are not nitrided.

Engineering systems operating under particle-laden turbulent flow regimes, such as slurry pumps, are prone to erosive wear, where the specific conditions of particle impingement are crucial for determining the wear rate of the eroding surface and thus its relevance for the mechanical or hydraulic system. However, the near-wall interactions under turbulent flows impose a challenge for the formulation and validation of experimental and numerical models that describe the particle’s trajectories close to the surface. This work analyzes the statistics of particle impacts obtained from a Large-Eddy Simulation (LES) with the Wall-Adapting Local Eddy-Viscosity (WALE) model of the flow and its consistency with experimental data on the statistical distributions of particle impact angle and impact direction determined in a slurry pot configuration. The resulting distributions of impact angle, impact direction, and particle velocity derived from the implemented CFD formulation produced characteristic values similar to those derived from experimental data. The LES-WALE approach used in this work offers shorter computational times and is shown valid by comparative analysis with direct simulation. The model’s applicability and prospective dynamic simulation of practical engineering cases are discussed.

In this paper, three kinds of Ni–20Cr coatings were deposited on SA516 substrate steel by cold-sprayed coating technique. Physical properties (such as hardness, surface roughness, and residual stress) and slurry erosion behavior (with impingement angles of 30∘ and 90∘) of cold-sprayed substrates have been evaluated. Moreover, a scanning electron microscope (SEM) examination has been performed to evaluate the morphological characterization of various coatings. It has been found that the residual stresses induced in the coated specimens exhibited compressive nature. Further, micro-hardness and surface roughness was observed to proliferate with the incorporation of titanium carbide (TiC) and rhenium (Re) in Ni–Cr coatings. Micro-hardness for Ni–20Cr+TiC and Ni–20Cr+TiC+Re was observed at 233.67 and 278.9 Hv, respectively, where Surface roughness for Ni–20Cr+TiC and Ni–20Cr+TiC+Re was observed at 9.86 and 11.68 μ m, respectively. All types of Ni–20Cr coatings were quite efficient in reducing the erosion rate of the SA516 steel as compared to uncoated SA516 and most prominent of all was Ni–20Cr+Tic+Re coating. It was observed that at 30∘, weight loss for Ni–20Cr, Ni–20Cr+TiC and Ni–20Cr+TiC+Re was up to 0.00027, 0.00015 and 0.00012 g/mm2, whereas at 90∘, weight loss was for Ni–20Cr, Ni–20Cr+TiC and Ni–20Cr+TiC+Re was up to 0.00024, 0.00014 and 0.00012 g/mm2. [ABSTRACT FROM AUTHOR]

Slurry erosion usually results in the form of damage to the materials of different components having underwater working domain. Numerous industries have suffered due to this kind of wear resulting in frequent breakdowns demanding repeated financial assistance and poor productivity. Properties and tribo-performance of materials related to distinct slurry applications play a significant role in arresting the slurry erosion wear. Slurry erosion depends on different parameters such as impact velocity, impingement angle, shape and size of erodent, slurry concentration and so on. These parameters differ from one application to another and accordingly, specific materials are selected knowing the extent and severity of slurry erosion wear. In the last decade, many authors studied parametrically the tribo-slurry erosion performance of materials, few of them correlated their investigations to the actual in situ conditions of applications. Various authors have analyzed the effect of operating parameters on the mechanism of erosion and conducted the comparative studies of different materials. Many of the investigators attempted to improve the properties and tribo-slurry erosion performance of materials through surface modification techniques; coating, reinforcement, heat treatment, thermo-mechanical process etc. This review is an effort to covers all such kind of explorations. [ABSTRACT FROM AUTHOR]

Hydrodynamic turbine and slurry pump components are frequently influenced by severe wear due to the impact of solid particles present in the water. A WC-based coatings deposited by thermal spray techniques is known for the protection against slurry erosion. In the present work, WC-Cr3C2-Ni powder was sprayed on a turbine steel substrate using high-velocity oxy-fuel (HVOF) and atmospheric plasma spray (APS) techniques. Microstructural and phase constitutions of as-sprayed coatings were examined. The effect of speed, slurry concentration and particle size on slurry erosion resistances of both coatings and substrate materials was comparatively studied in a slurry pot erosion tester. The results exhibit that the HVOF coating has better properties in terms of density, micro-hardness and slurry erosion resistance than those of APS coating. The improvement in slurry erosion resistance of bare turbine steel by using APS and HVOF coatings is approximately 37% and 62%, respectively. [ABSTRACT FROM AUTHOR]

Engineering systems operating under particle-laden turbulent flow regimes, such as slurry pumps, are prone to erosive wear, where the specific conditions of particle impingement are crucial for determining the wear rate of the eroding surface and thus its relevance for the mechanical or hydraulic system. However, the near-wall interactions under turbulent flows impose a challenge for the formulation and validation of experimental and numerical models that describe the particle's trajectories close to the surface. This work analyzes the statistics of particle impacts obtained from a Large-Eddy Simulation (LES) with the Wall-Adapting Local Eddy-Viscosity (WALE) model of the flow and its consistency with experimental data on the statistical distributions of particle impact angle and impact direction determined in a slurry pot configuration. The resulting distributions of impact angle, impact direction, and particle velocity derived from the implemented CFD formulation produced characteristic values similar to those derived from experimental data. The LES-WALE approach used in this work offers shorter computational times and is shown valid by comparative analysis with direct simulation. The model's applicability and prospective dynamic simulation of practical engineering cases are discussed. [ABSTRACT FROM AUTHOR]

In this paper, an investigation was carried out to test the suitability of potential additive materials in WOKA 3533 (WC-10Co4Cr) cermet HVOF coating subjected to slurry erosion in ash conditions. The additives namely molybdenum carbide, yttrium oxide, and zirconium oxide were added in equal percentages (3 wt.%) in WOKA cermet powder. High-velocity oxy-fuel (HVOF) spraying was performed to develop the additive-based WOKA cermet coatings. The slurry erosion in ash conditions was tested using the pot tester. Microstructural and mechanical properties of traditional and additive-based WOKA cermet coatings were also tested in the present study; for example, microstructure, crystalline phases of as-sprayed coatings, and microhardness. Results present a comparison of surface erosion wear of different cermet coatings. It was found that the yttrium oxide was a suitable additive for the WOKA cermet coatings than the molybdenum carbide. However, zirconium oxide is unsuitable for WOKA cermet coatings in erosion wear applications. [ABSTRACT FROM AUTHOR]

Slurry erosion poses a serious threat which causes damage to slurry handling equipment, as it leads to substantial expenditure owing to faults, downtime and material alternative costs. High velocity oxy fuel (HVOF) spraying method engaged to deposit defensive coating, particularly cermet coating, which can enhance substrates resistance to slurry erosion. In this analysis, HVOF coated conventional composite WC-10Co coatings on the steel substrate are used. The coating structures were analysed by SEM and XRD techniques. Furthermore, micro hardness, porosity and roughness were determined. Slurry erosion testing was conducted upon this coating to investigate the effects of rotating speed, impingement angle, slurry concentration, and exposure period on erosion behaviour. Empirical correlations have been developing through RSM approaches to anticipate the loss of mass in coating. Using the five levels, central composite design matrix, four variables has been employed to reduce the number of experimental runs. The relationship established may be efficiently used to assessment of the coating erosion rate with ninety five percent level of certainty. The research outcome indicates that the rotational speed is the predominant factor preceded by impinging angle, slurry composition and time.

Slurry erosion can cause severe damage and often constitutes a significant portion of the total production cost in many industries such as oil sands and mining. The most commonly used materials for such applications are metallic materials having a composite microstructure consisting of hard reinforcement phases in a more ductile metal matrix. Typical examples are high chromium white irons and tungsten carbide welding overlays. The main purpose of this work is to evaluate the scouring erosion resistance of such materials for applications in handling fine sand slurries and to introduce a wear model to help understand the correlation between erosion resistance and the characteristics of microstructures. Five high chromium white cast irons and four spray and fusion coatings composed of cast tungsten carbide particles and Ni–Cr–B–Si–Fe matrix have been studied using a Coriolis scouring erosion tester in a fine sand slurry. The relationship between the erosion resistance and different microstructure parameters was explored. For the chromium white cast irons, the erosion resistance increased with increase in carbide volume fraction but the spray and fusion coatings showed the opposite trend, i.e., their erosion resistance decreased with increase in the carbide volume fraction. No clear correlation was found between erosion resistance and free path for the spray and fusion coatings while for the chromium white cast irons, the erosion resistance was found to increase rather than decrease with increase in free path. To help explain the experimental results, a wear model has been proposed for the wear resistance of composite microstructures composed of a reinforcement phase (RP) and a metal matrix. In the model, the wear surface of the material is distinguished by four different features/regions, each having unique wear resistance. The rule of mixtures (ROM) for wear resistance is applied to formulate the wear resistance of the material with the above four wear surface features. It is shown that the results can be reasonably well explained based on the proposed model by using the total edge length, L , of the RP particles exposed on a unit area of the wear surface. • Find sand slurry scouring erosion of Cr white irons and WC coatings studied. • A rule of mixtures wear resistance model is proposed. • Wear surface is assumed to consist of four regions with distinctive wear resistance. • Carbide edge effect and shadow protective effect are considered. • Carbide edge length was found to be important parameter affecting wear resistance. [ABSTRACT FROM AUTHOR]