Erosion Resistance Research Articles

Effects of water temperature on soil aggregate stability between soils developed from different parent materials in the subtropical hilly area of China

Water temperature has an important effect on soil aggregate stability. In this study, six soils derived from different parent materials in the hilly region of southern China were selected, and the mean weight diameter (MWD), geometric mean diameter (GMD), and soil erodibility (K value) were measured under different water temperature conditions. The aim of this study was to investigate the influence of water temperature on soil aggregate stability and erodibility. As the water temperature increased from 5 °C to 40 °C, the average content of >5 mm water-stable aggregates decreased by 57.13 %, while the average content of <0.25 mm water-stable aggregates increased by 214.41 %. The MWD and GMD of the six different parent soil types exhibited a decreasing trend with increasing water temperature. The trend of the K value was opposite to that of these values. The influence of water temperature on soil aggregate stability is mainly attributed to the thermal effect on the viscosity of soil water and the expansion of clay minerals. As the water temperature increases, the water viscosity coefficient, water density and water surface tension gradually decrease. Moreover, the response of soil aggregate stability and erosion resistance to water temperature varies with soil depth and parent material type. The topsoil exhibits greater sensitivity to water temperature than does the subsoil. Shale (SH) soils and quartz sandstone (QS) soils exhibited higher sensitivities, and Quaternary red clay (QRC) soils exhibited the lowest sensitivity to water temperature among the six soils. This difference is mainly attributed to differences in the contents of expansive clay minerals and organic matter. These results indicate that soil aggregate stability and erosion resistance decrease with increasing water temperature, which may be one reason for severe soil erosion under extremely high temperature and rainfall conditions in the southern red soil hilly region during summer.

A novel remote sensing-based approach to determine loss of agricultural soils due to soil sealing — a case study in Germany

Soils provide habitat, regulation and utilization functions. Therefore, Germany aims to reduce soil sealing to 30 ha day-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-1}$$\\end{document} by 2030 and to eliminate it by 2050. About 55 ha day-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-1}$$\\end{document} of soil are damaged (average 2018–2021), but detailed information on its soil quality is lacking. This study proposes a new approach using geo-information and remote sensing data to assess agricultural soil loss in Lower Saxony and Brandenburg. Soil quality is assessed based on erosion resistance, runoff regulation, filter functions, yield potential and the Müncheberg Soil Quality Rating from 2006 to 2015. Data from the German Soil Map at a scale of 1:200,000 (BÜK 200), climate, topography, CORINE Land Cover (CLC) and Imperviousness Layer (IMCC), both provided by the Copernicus Land Monitoring Service (CLMS), are used to generate information on soil functions, potentials and agricultural soil loss due to sealing. For the first time, soil losses under arable land are assessed spatially, quantitatively and qualitatively. An estimate of the qualitative loss of agricultural soil in Germany between 2006 and 2015 is obtained by intersecting the soil evaluation results with the quantitative soil loss according to IMCC. Between 2006 and 2015, about 73,300 ha of land were sealed in Germany, affecting about 37,000 ha of agricultural soils. This corresponds to a sealing rate of 11 ha per day for Germany. In Lower Saxony and Brandenburg, agricultural soils were sealed at a rate of 1.9 ha day-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-1}$$\\end{document} and 0.8 ha day-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{-1}$$\\end{document} respectively, removing these soils from primary land use. In Lower Saxony, 75% of soils with moderate or better biotic yield potential have been removed from primary land use, while in Brandenburg this figure is as high as 88%. Implementing this approach can help decision-makers reassess sealed land and support Germany’s sustainable development strategy.

Experimental Investigation of Producer Gas Effects on Coated Pipelines in Biomass Downdraft Gasifier System

Abstract This research examines the performance of epoxy, ceramic, and graphene coatings on stainless steel 316 in a producer gas environment, focusing on corrosion and erosion resistance. This research aimed to identify the most effective coating for applications in harsh gasification environments. In this research, various analyses, including microstructural examination, hardness and weight measurements, FESEM analysis, and EDAX analysis, were conducted to evaluate the performance of the coatings. The producer gas was passed on to all the coated samples for a period of 100 hours. The significant findings include the superior corrosion and erosion resistance of ceramic-coated stainless steel, as evidenced by low weight fluctuations, maintained hardness levels, and elemental stability. Graphene coatings exhibit high hardness but increased porosity, raising concerns about durability, while epoxy coatings are vulnerable to gas-induced structural alterations. The inclusion rating analysis underscored the ceramic coatings' ability to preserve consistent material properties. Overall, ceramic coatings have emerged as the preferred option for gasification environments due to their structural resilience, inclusion integrity, and elemental stability. Considering the inclusion integrity, mechanical strength, weight stability, and elemental stability, ceramic-coated stainless steel 316 samples exhibit better resistance toward producer gas influence. This research contributes valuable insights for material selection in applications exposed to harsh gasification environments, emphasizing the importance of coating selection for long-term durability and performance.

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.

An investigation into the erosion and wear mechanisms observed in abradable ytterbium disilicate environmental barrier coatings

Abradable environmental barrier coatings (EBCs) are used to reduce clearances between blades and casings in the hottest parts of aero gas turbines, increasing the overall efficiency of the turbine, however, research into the mechanical performance of such coatings is limited. The aim of this work was to better understand the relationship between microstructure and erosion and wear performance in abradable EBCs, since publicly available literature regarding such coatings is scarce and the potential efficiency gains in gas turbines are significant. In this study, ytterbium disilicate abradable EBCs containing three different porosity levels (determined by fugitive polyester phase addition) were deposited using atmospheric plasma spraying with porosity levels of 8, 15 and 21.5% by area. These coatings were then characterised in numerous ways; the porosity was quantified, the thermal conductivity was measured, the superficial hardness and erosion resistance were measured, and finally, the coatings were subjected to a rig test designed to simulate in-service cutting mechanisms against a tipped turbine blade. The results show that increasing the level of porosity via increasing the amount of pore forming phase in the feedstock, led to reduced erosion resistance and improved cutting by a turbine blade.

Comparative erosion performance of HVOF and LVOF sprayed NiCrSiBCFe-WC-Co coating

Thermal spray coatings enhance one or more surface properties of engineering components. In this work, NiCrSiBCFe-WC-Co composite coating powder is deposited over SA213-T12 boiler steel using the high velocity oxy fuel spraying (HVOF) and low velocity oxy fuel spraying (LVOF) thermal spray methods to improve erosion performance. XRD and scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS) were used to examine the surfaces and constituents of as-deposited specimens, whereas SEM was used to investigate the eroded specimens. The erosion behaviours of developed coatings were investigated at 30° and 90° impact angles, 53 m/s and 400°C. XRD analysis of the HVOF coating showed an additional peaks of NiCo2O4, SiC and Ni2B with common peaks Ni, WC, W2C, Cr23C6 and C6(Cr,Co,Ni)23 to that of LVOF coating. HVOF-sprayed coating demonstrated higher microhardness and adhesion strength with lower porosity than LVOF-sprayed coating. The HVOF-sprayed NiCrSiBCFe-WC-Co coating demonstrated comparatively better erosion resistance than LVOF-sprayed NiCrSiBCFe-WC-Co coating, attributed to its superior properties. The mechanism of erosion, concerning the different characteristics of the coatings, is discussed.

Arc erosion resistance of Al2O3–Cu/35Mo composites reinforced by trace graphene oxide

In this study, Al2O3–Cu/35Mo composites were prepared by rapid hot-press sintering-internal oxidation method, and the materials were modified by adding trace amounts of graphene oxide (GO). The results show that the relative densities of the composites are above 99%, the γ-Al2O3 generated by internal oxidation is diffusely distributed on the copper matrix. The incorporation of GO produced a small number of hard MoC particles at the interface, which facilitated the interfacial bonding of the composites. In the 30 V DC, 10–30 A electrical contact test, the anode mass of the composites increases, while the cathode mass decreases. And GO reduces the total mass loss of the electric contact by 63.6%, 38.9%, 51.3% and 20.9%, respectively. A comparison of the electrical contact properties of the two materials showed that the addition of GO dispersed the concentrated erosion of the arc. At 10 A and 30 A, the arc energy is reduced by 75.5% and 12.5%, respectively. With the gradual increase in electric current, GO makes the Al2O3–Cu/35Mo composites more stable during the electric contact process, improves the anti-welding ability of the contact and reduces contact resistance.

Erosion Resistance of Heat-Treated Aluminum Cast Iron to Aluminum Alloy Melt

Erosion Resistance of Heat-Treated Aluminum Cast Iron to Aluminum Alloy Melt

Electroerosive Series of Metals for Electric Spark Deposition Based on Solving the Problem of Thermal Conductivity

The electrical erosion of Zn, Al, Zr, Ti, V, Fe, Ni, Co, Cr, Nb, Mo, Cu, and W was experimentally determined. For the first time a mixture of granules of the listed metals, taken in equal molar ratios, was used that acted as a non-localized electrode for the electric spark deposition of steel 35. A mathematical model is proposed so as to calculate the volume of molten metals under conditions of an electric discharge during electric spark deposition based on solving the problem of the thermal field on the electrodes using their thermophysical constants. Calculations for a wide range of metals that differ greatly in thermophysical properties allowed to conclude that the active heat source during a discharge is an order of magnitude narrower than the erosion zone and three orders of magnitude more powerful than previously theoretically assumed. The volumes of melting on metals per one discharge were calculated and the corresponding series of electrical erosion resistance of metals was constructed. It is shown that the developed theoretical series of electrical erosion resistance of metals better corresponds to experimental data in comparison with literature data.

Impacts of different slash disposals on soil and water erosion of high-intensity management Eucalyptus grandis × urophylla plantation

BackgroundThe slash disposal-burning forest-in high-intensity management Eucalyptus grandis × urophylla plantation has accelerated soil degradation. Statement of the problemSlash disposals is a contributing factor, but its specific role in the correlation between rainfall-runoff and soil erosion remains elusive. Objectiveshis study investigated the characteristics of rainfall-runoff and soil erosion resistance in different methods of slash disposals in plantation. MethodsThree methods of slash disposal, namely burning forest (BF), moving away (MA), and spreading evenly (SE), were established. A field simulation experiment of rainfall was conducted, and path analysis was used. ResultsThe findings revealed that the water holding, infiltrating properties and the time the rainfall-runoff generated of SE were increased by approximately 10∼20 %, 100 %, and 80 %, respectively, compared with BF and MA. Water loss, soil loss and nutrient loss were significantly reduced by 62.23 % and 61.56 %, 69.06 % and 49.55 %, and 58.8 % and 65.42 % in SE and BF compared to MA. Path analysis suggested that different from BF and MA, the correlation between soil water properties and rainfall-runoff factors in SE was weakened, simultaneously considering the result that SE had the lower proportions of silt for sediment component (75.31 %), it stabilized the soil structure. Conclusions and prospectConsequently, SE mitigated the erosion force by reducing rainfall-runoff and enhancing the anti-erosion of soil through improved water properties, making it a viable slash disposal. This work provides a detailed description of the soil erosion characteristics of plantation, including water, soil, and nutrient losses caused by rainfall-runoff, as well as the soil anti-erosion due to different slash disposals. These findings offer valuable insights for the management of high-intensity Eucalyptus grandis × urophylla plantations.

Spatial-temporal variation and correlation between vegetation coverage and soil conservation of Ten Kongdui watershed in the Yellow River basin

The Ten Kongdui watershed is an essential part of the upper Yellow River baisn of China. The ecosystem in this region has low stability and hazards of sandstorm and soil erosion are serious. By studying the spatio-temporal changes and spatial correlation between vegetation cover and soil conservation, the inhibition effect of vegetation on soil erosion in time and space can be clarified, and the driving factors of soil erosion in a certain area can be further explained. The research results provide data support for artificial vegetation construction and soil erosion control in the Yellow River basin in the future. In this study, the invest model was used to calculate the soil retention of the watershed, and then the spatial autocorrelation analysis was used to analyze the vegetation coverage and soil retention in space. The relationship between changes of the vegetation coverage and soil conservation during 2000–2020 in the Ten Kongdui watershed is analyzed in this paper. The research shows that: (1) During the research period, the vegetation coverage maintained an increasing trend in Ten Kongdui watershed; (2) From 2000 to 2020, with the increased vegetation coverage, soil retention increased, indicating that increasing vegetation coverage can effectively prevent soil erosion; and (3) Vegetation coverage and soil conservation presented a local spatial auto-correlation, Moran’s I index was less than 0, but the years from 2000 to 2020 witnessed gradual growth of the correlation coefficient. There are significant differences in spatial distribution. ‘High-high’ and ‘low-low’ are sporadically distributed in the sandstorm area on the middle reaches of Kubuqi and sporadically in the hilly and gully areas on the upper reaches. Moreover, ‘high-low’ and ‘low-high’ correlation coefficients were distributed in gully areas on the upper reaches and alluvial plains on the lower reaches. The alluvial plains on the lower reaches are mainly farmland ecosystems, with a high NDVI in the growing season but poor soil erosion resistance and weak soil conservation ability. The results emphasized the importance of vegetation coverage change in space for soil conservation of different type of underlying surfaces. The vegetation coverage change effects of soil conservation in plain terrain will be muted. This work provided a certain theory and criterion for us to further research the predictive model of soil erosion .

Abiotic origins of self‐organized ridge‐runnel patterns on tidal flats

AbstractStriking large‐scale spatial patterns in ecosystems, generated by self‐organization through biotic and abiotic feedback processes, influence ecosystem functioning and response to global environmental change. A remarkable example of this are the regular ridge‐runnel patterns found on tidal flats, which play an important role in mudflat‐marsh transitions. Yet the mechanisms driving their formation, and whether they are abiotic or biotic in origin, have not been elucidated. The underlying mechanisms are unraveled in this study through a combination of field measurements and targeted laboratory experiments. In the field, we find that on the ridges of the pattern, the sediment bed level is less dynamic and more resistant to erosion than in the runnels. In laboratory flume experiments, we find that erosion‐resistant surfaces, like those found on the ridges, can arise on time scales of hours to days due to the drying of the cohesive sediment bed, while this is prevented in waterlogged sediments in runnels. A disturbance‐recovery experiment on benthic algae then confirms that biological processes require a longer developmental period than the time scale at which we have observed drying‐induced erosion resistance to develop. Together, these results demonstrate that ridge‐runnel patterns begin from an abiotic initiation point that can subsequently provide a template for further biological establishment and self‐organization. Recognition of abiotic processes as catalysts of self‐organization can improve our understanding of ecosystem responses to environmental changes.

Baffle effect of exposed WC particles in the clearance on slurry erosion behavior of cemented carbide surface

Erosion damage of clearance fits is the major factor for the failure of metal-to-metal screw motors. In this study, the slurry erosion behavior of the WC-based laser cladding layer was investigated. It aimed to explore the effect of SiO2 particle concentration on the laser cladding layer. The experimental results indicate that the WC-based laser cladding layer exhibits excellent erosion resistance across various particle concentration environments. The presence of the 'baffle effect' resulted in the cladding layer demonstrating enhanced erosion resistance, particularly at high particle concentrations. The 'baffle effect' refers to exposed WC particles hindering the movement of SiO2 particles. As SiO2 particles continuously impact the clearance material surface, much of the matrix on the cladding surface is removed. The presence of remaining WC particles on the clearance material can impede the impact of particles in the slurry. The current results aim to offer experimental support for future investigations of surface strengthening methods for metal-to-metal screw motors.

Combined Pullout Tests And Wave Overtopping Simulations On Three Species-Rich Grass Covered Dikes In The Netherlands

Grass cover erosion by wave overtopping is a major failure mechanism for earthen dikes. Grass cover erosion resistance (represented by the critical velocity, Uc) can be assessed using full-scale, destructive tests with the wave overtopping simulator (WOS) in combination with the erosion model ‘cumulative overload method’ (COM). Although these tests provide valuable information, they are relatively expensive and time consuming. Therefore, a small-scale grass pullout test (GPT), which translates the vertical pullout force of a grass sod to a Uc, may be an attractive alternative. In this paper, based on comparative testing with the WOS and GPT on three species-rich grass covers on dikes in the Netherlands, we assess the correspondence between the Uc obtained with the WOS and GPT for species-rich grass covers. Ultimately, by also including historical tests, we aim to get more insight into the suitability of the GPT for quantitative erodibility assessment of grass covers in general. During testing with the WOS, no failure was observed for the tested grass cover sections. Therefore only a lower bound of the Uc could be derived. Results indicate that the estimated Uc with the GPT is around the lower bound values obtained with the WOS. This is in line with previous tests on conventional grass covers, for which the GPT provides a more conservative estimate of the Uc than the WOS. Adaptations in the translation from pullout force to Uc may correct for the negative bias and hence improve the reliability of the GPT for quantitative erodibility assessment. Several suggestions to adapt the GPT in future work are provided in this paper. These adaptations should be tested and validated for conventional as well as species-rich grass covers to guarantee the general applicability of the method.

The Preparation and Dust Suppression Performance Evaluation of Iron Ore Tailing-Based Cementitious Composites.

In order to comprehensively utilize iron ore tailings (IOTs), the possibility of using IOTs as raw materials for the preparation of cementitious composites (IOTCCs) was investigated, and IOTCC was further applied to mine interface pollution control. The mechanical properties, hydration products, wind erosion resistance, and freeze-thaw (F-T) cycle resistance of IOTCCs were evaluated rigorously. The activity index of iron tailings increased from 42% to 78% after grinding for 20 s. The IOTCC was prepared by blending 86% IOT, 10% ground granulated blast-furnace slag (GGBS), and 4% cement clinker. Meanwhile, the hydration products mainly comprised ettringite, calcium hydroxide, and C-S-H gel, and they were characterized via XRD, IR, and SEM. It was observed that ettringite and C-S-H gel were principally responsible for the strength development of IOTCC mortars with an increase in curing time. The results show that the kaolinite of the tailings was decomposed largely after mechanical activation, which promoted the cementitious property of IOT.

Research on the mechanism of chlorine corrosion resistance of graphite tailings modified recycled coarse aggregate concrete: Corrosion product transformation and multi-scale mathematical characterization model

This research investigated the impact of substituting sand with graphite tailings (GT) on the chloride ion erosion resistance of recycled aggregate concrete (RAC). The role of GT is to significantly inhibit the penetration of chloride ions into the interior and slow down the corrosion process. However, the durability of graphite tailings recycled aggregate concrete (GTRAC) still depends on the replacement rate of recycled aggregate. At the same time, a multi-scale dynamic model of physical adsorption-chemical binding-free transport and erosion of chloride ions in GTRAC were established based on unsteady viscous fluid force and molecular dynamics.

Strength and Erosion Resistance of Spinifex Fibre Reinforced Mudbrick

This study assesses the usability of natural materials available in Australia’s remote communities for making fibre-reinforced mudbricks. The present construction cost for housing in remote areas is too high to maintain the level of housing required for the remote Australian population. As this includes mostly First Nations communities, more culturally appropriate housing materials and construction methods are being considered. This study looks at mudbricks made from laterite soil reinforced by spinifex fibre, both available in abundance in remote communities. Hence, this material is more acceptable to communities as it is more sustainable, and the construction methods are more suited for First Nations engagement. Various mixes were tested for compressive strength and erosion resistance. Results suggest that spinifex can significantly improve compressive strength and reduce erosion effects; however, spinifex showed adverse effects at the early stage of the spray test. The results satisfy the minimum strength and erosion resistance requirements for construction and suggest that spinifex-reinforced mudbricks could potentially be considered as an alternative material in remote housing.

Feasibility of Microbially Induced Carbonate Precipitation to Enhance the Internal Stability of Loess under Zn-Contaminated Seepage Conditions

Loess is widely distributed in Northwestern China and serves as the preferred engineering construction material for anti-fouling barriers. Heavy metal contamination in soil presents significant challenges to the engineering safety of vulnerable loess structures. Hence, there is an urgent need to investigate the impact of heavy metal ions on their percolation performance. In order to investigate the effectiveness of microbially induced carbonate precipitation (MICP) using Sporosarcina pasturii (CGMCC1.3687) bacteria in reducing internal seepage erosion, a saturated permeability test was conducted on reshaped loess under constant water head saturation conditions. The response of loess to deionized water (DW) and ZnCl2 solution seepages was analyzed by monitoring changes in cation concentration over time, measuring Zeta potential, and using scanning electron microscopy (SEM). The results indicate that the hydrolysis of Zn2+ creates an acidic environment, leading to the dissolution of carbonate minerals in the loess, which enhances its permeability. The adsorption of Zn2+ ions and the resulting diffusion double-layer (DDL) effect reduce the thickness of the diffusion layer and increase the number of free water channels. Additionally, the permeability of loess exposed to ZnCl2 solution seepage significantly increased by 554.5% compared to loess exposed to deionized water (DW) seepage. Following the seepage of ZnCl2 solutions, changes in micropore area ratio were observed, decreasing by 48.80%, while mesopore areas increased by 23.9%. MICP treatment helps reduce erosion and volume shrinkage in contaminated loess. Carbonate precipitation enhances the erosion resistance of contaminated loess by absorbing or coating fine particles and creating bridging connections with coarse particles. These research results offer new perspectives on enhancing the seepage properties of saturated loess in the presence of heavy metal erosion and the geochemical mechanisms involved.

Impact of Meadow Degradations on the Probabilistic Distribution Patterns of Physical and Mechanical Indices of Rooted Soil in the Upper Regions of the Yellow River, China

The shear strength (particularly soil cohesion) of rooted soil is an important parameter that reflects the true erodibility of meadows, particularly in meadows experiencing different degrees of degradation, ranging from undegraded (UD) through to lightly degraded (LD) and from moderately degraded (MD) to heavily degraded (HD). The cohesion of rooted soil is controlled not only by the soil moisture content and its natural density, but also by roots (including not only their density, spatial distribution, and diameters, but also their tensile strength). This study aimed to improve the current understanding of the erosion resistance of rooted soil and elucidate the impact of meadow degradation on the physical–mechanical indices of rooted soil. Based on this discussion, a one-way analysis of variance was performed at significance levels of 0.05 and 0.01 to test the impact of degradation on the physical–mechanical indices of rooted soil across degradation. Furthermore, the probabilistic distributions of the physical–mechanical indices were described using normal, gamma, Weibull, and generalized extreme values (GEV). The Kolmogorov–Smirnov (KS) test was used to identify the optimal distribution based on p-values and the Pearson correlation coefficient was used to quantify the correlation between the cohesion of rooted soil and other indices. The one-way ANOVA indicated that the soil’s natural density and soil moisture content decreased firstly, followed by an increase, the root amount and cohesion decreased, the root content experienced an initial increasing and then decreasing trend, and the internal friction angle exhibited a stepwise increasing trend. The four distributions sufficiently described the actual distribution of data on the physical–mechanical indices of rooted soil, except for the internal friction angle in UD and MD soils and the soil moisture content in MD soil. Additionally, the KS tests showed that the optimal distribution depended on both the physical–mechanical indices themselves and the degree of degradation. The Pearson correlation analysis showed that the correlation between cohesion and the other physical–mechanical indices varied considerably depending on the degree of degradation.

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.