Slurry Erosion Resistance Research Articles

Rare earth-doped ceramic coatings: Analysis of microstructure, mechanical properties, and slurry Erosion resistance using high pressure-high velocity oxy-liquid fuel deposition

The high pressure-high velocity oxy liquid fuel (HP-HVOLF) is a current industry-adopted thermal spraying technique for developing high melting point powder coating over surfaces. In the current manuscript, the rare earth (La2O3/CeO2/Er2O3–0.3 wt%. each) doped and without rare earth doped carbide (WC-10Co-4Cr) coatings have been deployed on stainless steel (SS410) via HP-HVOLF process. The comparison among the properties of the substrate, without rare earth coating and rare earth oxides doped coatings have been characterized by conducting mechanical, microstructural, and slurry jet erosion analysis. The results show that the hardness, modulus of elasticity, and flexural strength of the cermet coating are considerably higher for rare earth-doped coatings than those without rare earth-doped coatings and substrates (SS410). The EDX (energy dispersive X-ray spectroscopy) has recognized the occurrence of different elements on the surface together with rare earth. Moreover, its compounds such as Co3W3C and W2C were inveterate using X-ray diffraction (XRD) measurements. The porosity level of the rare earth doped, and un-doped coatings are obtained to be less than 1 % and≥1 to ≤2 % respectively. Moreover, the rare earth-doped cermet coated surface shows hydrophobic behavior with a maximum water contact angle (WCA) of ≈129.4°. Furthermore, the slurry jet behavior of rare earth doped coating shows high wear resistance as compared to without RE doped coatings, indicating its potential for robust performance under erosive conditions.

Slurry Erosion Resistance, Morphology, and Machine Learning Modeling of Plasma-Sprayed Si3N4+TiC+VC and CrNi based Ceramic Coatings

This study presents a comprehensive analysis of the morphology, mechanical properties, erosion resistance, and machine learning modeling of Si3N4+TiC+VC and CrNi based ceramic coatings deposited via plasma spraying. The cross-sectional morphology analysis revealed good mechanical interlocking between the coatings and the substrate, with pores predominantly observed in the Si3N4+TiC+VC coating. The coating thicknesses were measured as follows: 260 μm for Si3N4+TiC+VC, 243 μm for Si3N4+TiC+VC blended with CrNi, and 232 μm for pure CrNi coating. Mechanical characterization showed that microhardness values ranged from 1933 HV for Si3N4+TiC+VC coating to 499 HV for pure CrNi coatings. Slurry erosion tests demonstrated that pure Si3N4+TiC+VC coating exhibited superior erosion resistance at 90º impingement angle compared to other coatings. Additionally, a rigorous evaluation of over 20 machine learning regression models revealed that Gaussian Process Regressors and Artificial Neural Network (ANN) with a layer size of 20, displayed satisfactory performance in modeling mass loss prediction. The erosion mechanisms observed in the coatings provided valuable insights into their response to slurry erosion, highlighting the influence of coating composition and impingement angles. The findings underscore the potential of Si3N4+TiC+VC ceramic coatings to enhance the erosion resistance of stainless steel, offering promising applications in various industries.

High-velocity oxy-fuel and high-velocity air fuel sprayed WC-Co-Cr coatings on solution-treated 21-4N steel for slurry and corrosion resistance

This study aims to fabricate WC-Co-Cr coatings on the solution-treated 21-4N steel utilizing high-velocity oxy-fuel (HVOF) and high-velocity air fuel (HVAF) techniques. The microstructure, hardness, surface quality, porosity, slurry erosion, and corrosion resistance of HVOF and HVAF coatings on solution-treated 21-4N steel were investigated and compared. The HVAF sprayed WC-Co-Cr coating exhibited dense structure, more hardness (1582 HV), greater fracture toughness (5.69 MPa m1/2), less decarburization, and lower porosity (0.97 %) as compared to HVOF sprayed coating. Further, slurry jet erosion tests and electrochemical corrosion tests provide a comprehensive evaluation of the coating’s performance under erosive and corrosive conditions. Eventually, the conclusive results of the study affirm the exceptional performance of the high-velocity air fuel sprayed WC-Co-Cr coating, demonstrating its superiority in both erosion and corrosion resistance compared to the high-velocity oxygen fuel sprayed coating.

Analyzing the mechanisms of Al2O3-TiO2 coating for enhanced slurry erosion resistance on AISI410 stainless steel

Analyzing the mechanisms of Al2O3-TiO2 coating for enhanced slurry erosion resistance on AISI410 stainless steel

Influence of microstructure on slurry erosion resistance of medium carbon high silicon steels

The present study compares slurry erosion resistance of austempered and tempered medium carbon high silicon steels. A 0.62C-1.91Si-0.85Mn-0.23Cr steel was subjected to austempering at 300, 350 and 400 °C for 10 min to develop a microstructure comprising of bainite and retained austenite. With the increase in the austempering temperature, the mechanical stability of retained austenite decreased, and the size of bainitic ferrite laths increased. As a result, strain hardening ability and toughness of the steels decreased with austempering temperature. Another set of steel with the same composition was quenched and tempered at 300, 450 and 550 °C for 60 min. An increase in the tempering temperature led to an increase in the size and fraction of carbides and a decrease in the mean free path and dislocation density. Strain hardening ability and toughness of tempered steels was substantially small than austempered steels. Both the austempered and tempered steels were subjected to slurry erosion. Austempered steels exhibited higher slurry erosion resistance as compared to tempered steels. Slurry erosion resistance of austempered steels has been noted to depend on the mechanical stability of retained austenite and the size of bainitic ferrite laths. Due to the difference in the extent of deformation-induced transformation of retained austenite into martensite in the steels austempered at different temperatures, number of mobile dislocations generated (to accommodate the dilatation due to transformation) in bainitic ferrite laths differed. A large number of mobile dislocations in the specimens austempered at 300 °C blunted the propagating crack and delayed the material loss during erosion. The erosion resistance of tempered steels was observed to decrease with an increase in tempering temperature. A large fraction of coarse carbides led to the formation of many decohesion sites in steels tempered at 450 and 550 °C. Further, a small number of mobile dislocations present per unit volume in the steels tempered at high temperatures could not resist the propagation of cracks nucleated from the decohesion sites leading to a high erosion rate in these steels.

Study on slurry erosion resistance and damage mechanism in cenosphere reinforced syntactic foams for light weight applications

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.

Mitigating slurry erosion in martensitic stainless steels through boronizing

In the present work, two grades of martensitic stainless steels (MSS) samples were boronized at 950 and 1000 °C for 6 h and then tempered at 600 °C for 2 h. These samples were subjected to a 36 h slurry erosion test, and their worn surfaces were characterized using optical profiling, SEM and XRD. Boronized samples exhibit significant enhancement in erosion resistance. SEM micrographs reveal minimal cracks and indentations while XRD shows presence of iron borides on eroded surface. Results suggest that boronizing temperature significantly enhances slurry erosion resistance of MSS used in hydro turbines, making them more efficient and sustainable.

Influence of laser texturing along with PTFE topcoat on slurry and cavitation erosion resistance of HVOF sprayed VC coating

This research investigates the slurry and cavitation erosion resistance of a polytetrafluoroethylene (PTFE) top-coat applied to standalone high velocity oxy-fuel (HVOF) sprayed and laser textured Vanadium Carbide (VC) coating over SS316 steel. The static contact angle, microstructural characterization, EDS mapping, microhardness, fracture toughness, elastic modulus, slurry erosion, and cavitation erosion of all the samples namely SS316, HVOF sprayed VC, Laser textured VC, and PTFE modified VC were evaluated. Results demonstrate that the inclusion of a PTFE top-coat significantly enhances the erosion resistance over HVOF sprayed and laser textured VC coatings. Further, the laser textured VC surface was also found to be successful in reducing the slurry and cavitation erosion of SS316 steel, which could be attributed to its higher microhardness, presence of circular textures, and higher H/E ratio. When the failure mechanism was examined using SEM images, it was found that brittle failure occurred on hard surfaces while ductile failure occurred on soft surfaces.

Microstructure evolution and erosion behaviour of thermally sprayed AlCoCrNiMo0.1 high entropy alloy coating

Novel AlCoCrNiMox (x = 0.1 wt%) non-equiatomic high entropy alloy (HEA) powders were synthesized by mechanical alloying. A single solid-solution was formed. X-Ray Diffraction (XRD) analysis of milled powders reveals a BCC phase after 20 h of milling. Field emission scanning electron microscopy (FESEM) with EDAX mapping confirmed the formation of a homogenous mixture. The milled alloy was coated onto a 316 steel substrate using High-velocity Oxy-fuel (HVOF) coating. The slurry erosion resistance exhibited by the coating was tested using Water-jet Erosion tester with 24 m/s to 30 m/s jet velocity at 30°, 45°, 60°, and 90° angular impingement. Spallation due to adhesion with subsequent layered lamellae fracture was observed to occur during erosion.

Improving erosion resistance through solution treatment of nitronic and martensitic steels for slurry erosive applications

Erosive wear is a general phenomenon in moving underwater parts of various types of equipment and slurry transportation. Materials with high erosion resistance are recommended for such applications. Currently used martensitic steel can be replaced with nitrogen containing austenitic stainless-steel grades 21-4 N and 23-8 N due to higher erosion resistance. This paper investigates the pathway to enhance the slurry erosion resistance of nitronic steels and evaluates its feasibility to replace currently used martensitic steel for heavy slurry erosive applications. Solution treatment was observed as a potential pathway to improve slurry erosion resistance and mechanical properties of the selected steels where specimens were subjected to solution treatment at 950 °C and 1150 °C. After the solution treatment, reduced carbide volume and fine distribution in the nitrogen alloyed austenitic microstructure resulted in higher erosion resistance. Nitronic steel grades resulted in low cumulative weight loss or high erosion resistance than martensitic steel for as-received and solution-treated samples. Solution treatment resulted in a maximum reduction in cumulative weight loss for martensitic steel, 21-4 N and 23-8 N was 10 wt%, 14.2 wt%, and 18.18 wt%, respectively, at 90° impingement angle. The erosion mechanisms observed at different impingement angles were different for both nitrogen alloyed and martensitic steels. The erosion mechanism was primarily deformation at 90° impingement angle, whereas at 30° impingement angle, the mechanism was lip formation, detachment, and ploughing.

Wetting and erosive behavior of VC-TiC + CuNi-Cr based coatings developed by HVOF: Role of laser texturing

Laser texturing method was used in the current study to create a micro-textured surface over SS316 steel with HVOF (High Velocity Oxy-fuel) sprayed VC-TiC and CuNi-Cr based coatings. The static contact angle, cross-sectional characterization, hardness, EDS mapping, surface roughness, porosity percentage, XRD analysis, bond strength and slurry erosion resistance of textured and non-textured surfaces were measured. Slurry erosion experiments were carried out in accordance with ASTM G-73 standards. According to the findings, laser texturing was found as an effective technique for increasing the static contact angle of the surfaces, which in turn increases the slurry erosion resistance of the surfaces. SEM images were used to analyze the failure mechanism, and it was discovered that hard surfaces experienced a brittle mode of failure, whereas soft surfaces experienced a ductile mode of failure.

Enhanced slurry erosion resistance of low friction and highly hydrophobic halloysite-fluoro-polysilsesquioxane coatings

Multifunctional coatings were obtained by a sol-gel co-condensation of a fluorinated silane and tetraethoxysilane over activated Halloysite nanotubes (hHNT). They were applied onto epoxy based substrates (neat epoxy or hHNT loaded) with different curing conditions. The coatings characterization showed low friction and high hydrophobicity. The coefficient of friction against stainless steel was 0.1, according to the nanoscratch test and the advancing contact angles reached values in the range 135–145°. The materials were subjected to a slurry erosion test under high speed flow condition and wettability was used to characterize the surface integrity over erosion-cumulative time periods. Fluorine containing coatings exhibited an outstanding resistance to the high speed slurry erosion (HSSE). After 1 h of HSSE test, average advancing contact angles of 145° were measured for the fluorinated samples. The high hydrophobicity of the coatings showed a correlation with the erosion resistance, while the substrate showed no effect. An explanation of the cushioning effect of hydrophobicity upon erosion wear is given, based on wall-detached eddies on the boundary layer.

Investigations on erosion performance of carbon fiber–epoxy-based composite adhesion on 16Cr5Ni steel

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.

Ann Supported Study on the Performance and Slurry Erosion Resistance of Thermal Sprayed Wc20cr3c27ni Coatings

Ann Supported Study on the Performance and Slurry Erosion Resistance of Thermal Sprayed Wc20cr3c27ni Coatings

DEVELOPMENT AND PERFORMANCE ANALYSIS OF Ni–15Cr2O3–5TiO2 AND Ni–15Al2O3–5TiO2 HVOF COATINGS IN EROSIVE FLY ASH SLURRY

This study is focused on improving the mechanical properties and slurry erosion resistance of traditional Ni–20Al2O3 and Ni–20Cr2O3 thermal spray coatings by reducing the 5% of Al2O3 and Cr2O3, respectively, and addition of 5% TiO2 feedstock in both coatings. Thermal sprayed powders were thermally sprayed on SS-420 substrates with high-velocity oxy-fuel (HVOF) method. A lab-scale pot tester was used to conduct the wear testing at low rotating speeds of 750, 1000, 1250, and 1500 rpm. To create severe accelerated conditions, a high mass flux (35–50 wt.%) of fly ash particles was used. Multi-sized fly ash slurries ranging from [Formula: see text][Formula: see text][Formula: see text]m to 250[Formula: see text][Formula: see text]m were used during the experiments to evaluate the impact of particle size fraction on the erosion over a 30–120 min time-period. Coatings’ surface characterization was done to examine more about their composition. According to the findings, the addition of 5% TiO2 powder to both Ni–15%Al2O3 and Ni–15%Cr2O3 coatings significantly improved their wear resistance of SS-420. This occurred because of the enhancement of hardness as well as brittleness by 5% TiO2 in matrix of Ni–15%Cr2O3 and Ni–15%Al2O3 coatings. Moreover, TiO2 particles aid in strengthening of Cr2O3 and Al2O3 reinforcements and the binding with matrix. Also, the results showed that Ni–15Cr2O3–5TiO2 coating showed superior wear resistance compared to Ni–15Al2O3–5TiO2 coating.

INFLUENCE OF VELOCITY, CONCENTRATION, AND SIZE OF SILT PARTICLES ON EROSION OF THERMAL SPRAYED Ni/TiO2/Al2O3 COATINGS

The presence of silt sediments in the flowing river is the primary reason for the severe failure of hydro-power turbine components. This study insights the effect of erosion parameters on the performance of two multi-dimensional novel compositions (namely Ni-40TiO2 and Ni-20TiO2-20Al2O3) developed on the CA6NM turbine steel by high velocity flame spray (HVFS) method. The Ni-40TiO2 coating with lower porosity, higher fracture toughness, and microhardness, showed the highest slurry erosion resistance than the other counterparts. This outstanding performance is attributed to the uniform distribution of the multi-dimensional TiO2 grains in the coating, which effectively reduces the material loss rate during slurry erosion. The Ni-40TiO2 coating indicated a mixed mechanism of material removal, while the brittle mechanism was observed in the case of Ni-20TiO2-20Al2O3 coating. A model has been proposed to estimate the erosion rate of these proposed coatings.

Improvement in Slurry Erosion and Corrosion Resistance of Plasma-Sprayed Fly Ash Coatings for Marine Applications.

Fly ash (FA), a multicompound mineral, is an industrial waste produced during coal burning in thermal power stations. It has been regarded as the most environmentally hazardous material. Furthermore, handling FA has been a significant challenge for many developing countries. Therefore, researchers have been exhorted to enhance its usage to counter its handling issues. FA is enriched with mullite, silica, and alumina. Having such mineralogy, FA can be envisaged as a promising candidate for combating erosion and corrosion in marine environments. With this motivation, the research aims to deposit as-received FA using the plasma-spraying technique onto a marine-grade steel substrate without additives and assess the performance of such coatings for erosion and corrosion properties. The coating has exhibited more than 100% improvement in microhardness. The erosion resistance was improved by ∼11% compared to that of the uncoated sample, which is attributed to the hardness to elastic modulus ratio (H/E) and its unique mineralogy. The minor improvement in erosion resistance was attributed to the coating’s poor fracture toughness. The erosion study shows that slurry concentration and rotational speeds were the most influential parameters. The scar depth was significantly shallower for FA-coated samples. The corrosion resistance has improved only by ∼13.49%, owing to the porous nature of the coating. Therefore, such coatings with appropriate improvements in their properties are expected to assuage both environmental and industrial challenges.

Comparison of erosion performance of uncladded and WC-based laser cladded SS304 and SS410 steels

Myriad hydro materials have been encountered with the severe attacks of eroded particles during the operation, leading to degradation of target material and economic loss. In this study, Colmonoy-6+WC powders were deposited with the help of the laser cladding method on the bare SS304 and SS410 steel surfaces. Distinct properties of cladded surfaces, such as mechanical as well as metallurgical properties, were investigated. The influence of slurry erosion parameters like angle of impact and impact velocity of eroded particles on the cladded as well as uncladded steel specimen was analysed. Under all slurry erosion conditions, there was an escalation in slurry erosion resistance in the case of cladded steel as that of as-received steel specimens. In slurry erosion, the influence of the impact velocity of erodent particles is more against the impact angle. The scanning electron microscopy images of eroded uncoated steel specimens represent ductile behaviour along with the formation lip, ploughing etc., while eroded cladded steels exhibit brittle behaviour.

Study on the slurry erosion wear of polycrystalline diamond compacts for application in fluidic oscillators

Fluidic oscillator made of tungsten carbide, the core component of the fluidic hammer, has a significantly reduced service life under the erosion wear of drilling fluids with solid particles. Polycrystalline diamond composite (PDC) has the potential to solve this issue due to its extremely high hardness and wear resistance benefits. However, few studies on the slurry erosion wear of PDC have been reported. In this paper, a modified slurry erosion experimental device based on submerged abrasive water jets was used to study the erosion resistance of four grades of PDCs with grain sizes of 2–3, 5, 10 and 25 μm respectively. The erosion surface of the damaged PDC was observed by scanning electron microscope (SEM) and the erosive mechanism of the PDC was analyzed. The experimental results showed that PDC had excellent slurry erosion resistance. The erosion rate of PDC was 1/192–1/43 of that of tungsten carbide when the jet velocity was 100 m/s. The erosion rates of PDC increased with the rise of jet velocity, impact angle and erodent particle size. In addition, the erosion performance of debris represented by quartz to PDC is greater than that of weighting agents represented by barite and hematite. Further research also showed that PDC with fine grain has greater erosion resistance than PDC with coarse grain, except PDC2 ~ 3. At a high impact angle, the erosive mechanism was forming the craters due to the crushing of diamond grains and the pits due to the overall pullout of diamond grains, while at a low impact angle, the erosive mechanism was ploughing and forming directional craters.

The effect of microstructure and mechanical properties on the slurry erosion behavior of carbide-free bainitic and martensitic steel

The effect of microstructure and mechanical properties on the slurry erosion behavior of carbide-free bainitic (CFB) steel, austempered at 350, 400 and 450 °C and quenched and tempered martensitic (QT) steel, tempered at 300, 400 and 500 °C has been investigated using slurry pot tester and silica sand erodent particles. The samples were tested for 15 h with a rotating speed of 1000 rpm. The result shows that the QT steel has better erosion resistance than the CFB steel. The retained austenite (RA) phase fraction (17.75%) in 350 °C austempered sample, which provides erosion resistance by transformation-induced plasticity effect, is sufficient for outstanding erosion performance among the CFB steels. However, this RA phase fraction in CFB steel is inadequate to provide better erosion resistance than the QT steel. Among all the samples tested, the sample which is tempered at 300 °C shows the best slurry erosion resistance. The analysis of the results suggests that the hardness and transformation-induced plasticity associated with RA phase fraction, are the deciding factors for erosion resistance in QT and CFB steel, respectively. The material removal mechanism in the CFB steel is the crater formation leading to fatigue failure of lips and coalescence of micro-craters, whereas in QT steel it is only fatigue failure of lips.