Crater Formation Research Articles

Quantification of Impact‐Induced Melt Production in Numerical Modeling Revisited

AbstractMelting and vaporization of rocks in impact cratering is mostly attributed to be a consequence of shock compression. However, other mechanism such as plastic work and decompression by structural uplift also contribute to melt production. In this study we expand the commonly used method to determine shock‐induced melting in numerical models from the peak shock pressure by a new approach to account for additional heating due plastic work and internal friction. We compare our new approach with the straight‐forward method to simply quantify melting from the temperature relative to the solidus temperature at any arbitrary point in time in the course of crater formation. This much simpler method does account for plastic work but suffers from reduced accuracy due to numerical diffusion inherent to ongoing advection in impact crater formation models. We demonstrate that our new approach is more accurate than previous methods in particular for quantitative determination of impact melt distribution in final crater structures. In addition, we assess the contribution of plastic work to the overall melt volume and find, that melting is dominated by plastic work for impacts at velocities smaller than 7.5–12.5 km/s in rocks, depending on the material strength. At higher impact velocities shock compression is the dominating mechanism for melting. Here, the conventional peak shock pressure method provides similar results compared with our new model. Our method serves as a powerful tool to accurately determine impact‐induced heating in particular at relatively low‐velocity impacts.

Evidence for high-velocity solid dust generation induced by runaway electron impact in FTU

Post-mortem and in situ evidence is presented in favor of the generation of high-velocity solid dust during the explosion-like interaction of runaway electrons with metallic plasma-facing components in FTU. The freshly-produced solid dust is the source of secondary de-localized wall damage through high-velocity impacts that lead to the formation of craters, which have been reproduced in dedicated light gas gun impact tests. This novel mechanism, of potential importance for ITER and DEMO, is further supported by surface analysis, multiple theoretical arguments and dust dynamics modeling.

Low spatial frequency laser-induced periodic surface structures in fused silica inscribed by widely tunable femtosecond laser pulses

The formation and evolution of laser-induced periodic surface structures in fused silica under irradiation of widely tunable (in the 1–3 upmum range) linearly polarized femtosecond (200 fs) pulses was studied experimentally. The structures were inscribed in high fluence regime (exceeding the surface ablation threshold for a single pulse) and characterized by using scanning electron microscopy and two dimensional Fourier transform. The results revealed rapid (after irradiation with a few successive pulses) formation of periodic laser-induced periodic surface structures aligned parallel to laser polarization, whose period increases with increasing the inscription wavelength, obeying the lambda /n law. With further increase of number of pulses, the generated structures gradually reorganize into laser polarization-independent low spatial frequency annular structures associated with formation of the damage crater, which fully established after irradiation with a few tens of successive laser pulses. This particular evolution scenario was observed over the entire wavelength tuning range of incident pulses.

The probability analysis of ejecta particles damaging a spacecraft operating around asteroids after an artificial impact experiment: Hayabusa 2 ’s SCI operation safety study

On 5 April 2019, the Hayabusa 2 spacecraft performed the first successful artificial impact experiment on an asteroid. The Small Carry-on Impactor (SCI) device was deployed at an altitude of 500 m above Ryugu’s surface. The 2 kg copper projectile hit Ryugu’s surface in 40 min and caused the formation of an artificial crater 14.5 m in diameter. Once the SCI was deployed, the Hayabusa 2 spacecraft performed a two-week escape trajectory reaching altitudes as far as 120 km from Ryugu. The spacecraft then returned to its nominal position at 20 km altitude (Home-Position) from Ryugu for hovering control. This was done to prevent ejecta particles from seriously damaging the spacecraft and compromising its functionality. In this article, we present a method to forecast the daily probability of spacecraft damage along the selected nominal escape trajectory due to the debris cloud formed by an artificial impact. The result of the damage analysis confirmed that the selected escape trajectory experienced a small number of particle collisions under the design threshold, which would not have resulted in damage. Indeed, no damage was reported on the Hayabusa 2 spacecraft and it kept operating normally after the SCI operation. The method here presented serves as a guideline for post-impact mission operations to forecast and estimate the probability of damage to spacecraft or CubeSats operating near a small celestial body after an artificial impact experiment has occurred.

Microstructure and Surface Topography Study of Nanolayered TiAlN/CrN Hard Coating

The microstructure and surface topography of PVD hard coatings are among the most important properties, as they significantly determine their mechanical, tribological and other properties. In this study, we systematically analyzed the microstructure and topography of a TiAlN/CrN nanolayer coating (NL-TiAlN/CrN), not only because such coatings possess better mechanical and tribological properties than TiAlN and CrN monolayer coatings, mainly because the contours of the individual layers, in the cross-sectional STEM or SEM images of such coatings, make it easier to follow topographic and microstructural changes that occurred during its growth. We investigated the effects of the substrate rotation modes on the microstructure and surface topography of the NL-TiAlN/CrN coating, as well as on the periodicity of the nanolayer structure. The influence of the substrate material and the ion etching methods were also studied, while special attention was given to the interlayer roughness and influence of non-metallic inclusions in the steel substrates on the growth of the coating. The topographical features of the NL-TiAlN/CrN coating surface are correlated with the observations from the cross-sectional TEM and FIB analysis. Selected non-metallic inclusions, covered by the NL-TiAlN/CrN coating, were prepared for SEM and STEM analyses by the focused ion beam. The same inclusions were analyzed prior to and after deposition. We found that substrate rotation modes substantially influence the microstructure, surface topography and periodicity of the NL-TiAlN/CrN layer. Non-metallic inclusions in the substrates cause the formation of shallow craters or protrusions, depending on their net removal rates during the substrate pretreatment (polishing and ion etching), as compared to the matrix.

Improving the Erosion Behavior of Inconel 625 Substrate by PTA-Deposited Stellite6/B4C Composite Cladding

The purpose of this study was to improve the erosion behavior of Inconel 625 alloy by plasma transferred arc-deposited stellite6/B4C composite cladding. For this purpose, 5 wt.% of boron carbide was added to the stellite6 clad. Phase analysis and microstructure evaluation were conducted by Optical Microscope, Field Emission Scanning Electron Microscope (FESEM), and Energy-dispersive Spectroscopy (EDS). Solid particle erosion tests with silica particles at 30˚ and 90˚ impact angles were performed to study the erosion behavior. Eroded surfaces were observed by SEM. Investigations showed that the addition of boron carbide particles caused finer microstructure in composite cladding. Moreover, hardness increased with adding boron carbide. Maximum erosion resistance was achieved at 30˚ impact angle. The weight loss of composite cladding were 20 % and 33 % compared to those obtained in Inconel 625 substrate and stellite6 cladding, respectively. The weight loss of the claddings and substrate showed negligible difference at 90˚ impact angle. The dominant mechanism of erosion for composite cladding at 30˚ impact angle was suggested to be cutting and detachment of reinforcing particles. Crater formation was found the predominant mechanism of erosion at 90˚ impact angle.

Meteorite impact crater positions based on paleo-positions and its unrestrained latitudinal distribution

The paleo-positions of terrestrial meteorite impact craters along with distance and displacement registered since formation due to plate tectonics were deciphered using GPlates, an interactive GIS-based plate tectonic reconstruction and modeling software. The results of the study are intriguing as several craters have traversed across the globe, both from the Eastern to Western hemisphere and from the Southern to Northern hemisphere, and vice versa. The oldest crater studied was Foelsche, which traversed from the Southern to Northern hemisphere and from the Western to Eastern hemisphere while covering a distance of 39080 ​km in the past 981 million years and recording a relatively shorter displacement of 10470 ​km. On the other hand, Jänisjärvi and Suvasvesi South have traveled longer distances (27781 and 29050 ​km, respectively) and are among the most displaced craters (17400 and 16988 ​km, respectively). Similarly, the paleo-position, distance, and displacement for all craters, with ages <1100 ​Ma, were computed in the study. Based on the derived paleo-position, we have accessed the possibility of any selective distribution of craters across different latitudinal segments. As Earth is a planet that recorded dynamic variations in the terrestrial surface area across different geological ages, calculating the same was an arduous task. The land area within each of the three latitudinal segments, viz. 0–30°, 30–60°, and 60–90°, in which a crater formed was calculated for the geological time corresponding to an impact cratering event. This calculated land area within the respective latitudinal zone at each instance of a crater's formation was then compared with the total land area on Earth. The results showed that 0–30° and 30–60° segments have equal crater frequencies whereas the 60–90° segment has a lesser frequency. The latitudinal crater distribution on Earth was then compared with Moon and Mars. The results revealed that there is a non-selective distribution of terrestrial impact craters across different latitudinal segments, indicating a non-perceivable latitudinal dependency for impact events. • 192 Earth impact craters, formed after 1100 ​Ma, were reconstructed to its paleo-position. • The distance and displacement recorded by the craters due to plate tectonics is computed. • Latitudinal distribution of craters was studied and showed no major dependency on latitudes. • The latitudinal distribution was correlated with Moon and Mars.

Effects of Impact and Target Parameters on the Results of a Kinetic Impactor: Predictions for the Double Asteroid Redirection Test (DART) Mission

The Double Asteroid Redirection Test (DART) spacecraft will impact into the asteroid Dimorphos on 2022 September 26 as a test of the kinetic impactor technique for planetary defense. The efficiency of the deflection following a kinetic impactor can be represented using the momentum enhancement factor, β, which is dependent on factors such as impact geometry and the specific target material properties. Currently, very little is known about Dimorphos and its material properties, which introduces uncertainty in the results of the deflection efficiency observables, including crater formation, ejecta distribution, and β. The DART Impact Modeling Working Group (IWG) is responsible for using impact simulations to better understand the results of the DART impact. Pre-impact simulation studies also provide considerable insight into how different properties and impact scenarios affect momentum enhancement following a kinetic impact. This insight provides a basis for predicting the effects of the DART impact and the first understanding of how to interpret results following the encounter. Following the DART impact, the knowledge gained from these studies will inform the initial simulations that will recreate the impact conditions, including providing estimates for potential material properties of Dimorphos and β resulting from DART’s impact. This paper summarizes, at a high level, what has been learned from the IWG simulations and experiments in preparation for the DART impact. While unknown, estimates for reasonable potential material properties of Dimorphos provide predictions for β of 1–5, depending on end-member cases in the strength regime.

Complex Crater Formation by Oblique Impacts on the Earth and Moon

AbstractAlmost all meteorite impacts occur at oblique incidence angles, but the effect of impact angle on crater size is not well understood, especially for large craters. To improve oblique impact crater scaling, we present a suite of simulations of complex crater formation on Earth and the Moon over a range of impact angles, velocities and impactor sizes. We show that crater diameter is larger than predicted by existing scaling relationships for oblique impacts; there is little dependence on obliquity for impacts steeper than 45° from the horizontal. Crater depth, volume and diameter depend on impact angle in different ways—relatively shallower craters are formed by more oblique impacts. Our simulation results have implications for how crater populations are determined from impactor populations and vice‐versa. They suggest that existing approaches to account for impact obliquity may underestimate the number of complex craters larger than a given size by as much as one‐third.

The effect of indium–tin oxide coatings on the formation of craters on glass surfaces under the impact of high-velocity microparticles

This article considers the problem of improved mechanical properties and protection of glass materials in optical systems of space vehicles. One the possible methods to solve the problem is the formation of multi-phase nanocomposite shock-resistant transparent coatings on the surface of glass plates. Considerable attention is paid to the application of indium–tin oxide (ITO) coatings on the surface of quartz glass pieces deposited by the method of pulsed magnetron sputtering. Such coatings demonstrate the highest properties. The optical characteristics of ITO coatings were studied in a range of wavelengths of 200–1100 nm. It was shown that in the visible spectrum they remain transparent. The structure and phase composition of indium tin oxide coating, basically, contains nanocrystalline In2O3 phase, which is indicated by the diffraction reflexes on obtained electron diffraction patterns and X-ray diagrams.It was unveiled that the deposited ITO-based coatings possess resistance to the shock impact of hyper-velocity iron microparticles. They can appreciably reduce surface density of the craters formed on the surface of glass plates under the impacts of solid microparticles due to increased strength and cracking resistance of the glass specimens. The character of alteration of the crater density of the glass surface with the coating is explained by the superposition of two mechanisms: reinforcement of the surface layer of glass due to deposited nanocomposite coating and supplementary dissipation of the energy of the normal shock wave that excites generation and propagation of secondary surface waves at the interface of heterogeneous layers of the ceramic coating and quartz.

Toward a high-fidelity model for the identification of underground gas flow regimes resulting from buried pipeline releases

The quantitative characterization of underground transport phenomena remains challenging due to the complex behavior of the gas movement in soil. Conversely, this inhibits the accurate prediction of the risk arising from the underground transport of hazardous materials. This work proposed and qualitatively evaluated a computational model that spans a wide range of underground gas flow regimes, ranging from gas migration, to ground uplift, and crater formation, depending on the release characteristics. The model followed the multiphase Eulerian approach and adopted the standard k-ω turbulence model and the kinetic theory of granular flow for the ground description with the Syamlal-O’Brien granular viscosity expression. The model's optimum configuration was checked against experimental data using a new mechanistic approach to link the qualitative observations with quantitative model outputs. The effect of pipeline pressure, burial depth, and release orientation on the regime was studied and the outcomes were utilized to enhance a literature nomograph for the flow regime identification. Emphasis was given to fill in the literature gaps and improve the delineation of the boundaries between the regimes rather than deriving specific quantities. The resulted nomograph is a cost-effective screening tool to identify the regime and select among the available strategies of risk assessment.

Film Instability Induced by Swelling and Drying.

Poly(2-vinyl pyridine), P2VP, films display a surface pattern of craters in a dried state after being immersed in aqueous solutions containing HAuCl4 and its mixtures with low contents of K2CO3. The morphologies of craters indicate that the formation of craters involves three stages through film blistering and drying: (i) the permeability of water and solutes to swell P2VP films, (ii) partial wetting of liquid droplets near the substrate interface in the presence of the P2VP film, and (iii) evaporation-driven flows. The three stages produce the swelling pressure, Laplace pressure, and interplays among capillary flows, Marangoni flows, and pinning effects, respectively, by which craters of different dimensions and morphologies are obtained. The first stage softens the P2VP films and produces swelling pressure. This stage relies on interactions between AuCl4- ions, water, and protonated P2VP chains. The second stage produces liquid droplets inside the film and near the substrate interface. The surface tensions of those liquid droplets at contact lines deform swollen P2VP films. Changing film thicknesses or substrate types alters craters' lateral dimension and depth. The results indicate that film thicknesses and substrate interface energies influence the shape and dimension of liquid droplets on the substrate interface. The third stage determines morphologies of craters through interplays among capillary flows, Marangoni flows, and pinning/depinning events.

Determination of Cooling Rate and Temperature Gradient during Formation of Cathode Spot Craters in a Vacuum Arc

Due to the extreme thermal conditions and short lifetimes, experimental exploration of cathode spots in vacuum arcs is very difficult. The intensive heat in the cathode spot is believed to be generated by ion bombardment and by Joule heating. However, thermal conditions occurring inside the re-melted material in craters created by cathode spots are not accurately known. During the exposure to cathodic arc plasmas, an Al-Cr cathode’s surface was locally melted by successive ignition and extinction of cathode spots. The melted layer, that quickly solidified, was characterized by the formation of several thin layers with a thickness of a few micrometers that were stacked on top of each other. The corresponding solidification patterns displayed cellular and dendritic microstructures. A phase field-based model was used to simulate and determine the thermal process conditions that led to the dendritic structures observed within the re-melted layer. Different combinations of cooling rates and temperature gradients were numerical explored to determine the most probable thermal conditions under which the cathode material re-solidifies. The results showed that the material in the vicinity of the cathode spot crater re-solidified under the condition of a cooling rate of about 3 × 105 K/s and a temperature gradient of about 6 × 107 K/m. These results constitute valuable data for the validation of numerical models dedicated to cathode spot formation.

Femtosecond Laser Direct Writing of Antireflection Microstructures on the Front and Back Sides of a GaSe Crystal

The development of antireflection coatings is crucially important to improve the performance of various photonic devices, for example, to increase the efficiency of harmonic generators based on high-refractive index crystals with significant Fresnel losses. A promising technique for the reducing of radiation reflection is to change the refractive index by fabrication of antireflection microstructures (ARM) on the surface. This paper presents the results of ARM direct writing on the surfaces of a nonlinear GaSe crystal (of ε modification, according to Raman and photoluminescence spectroscopy data) using fs laser radiation and a multiples approach. An increase in transmission from 65% to 80% for an ARM fabricated on one side of the crystal and up to 94% for ARMs fabricated on both sides is demonstrated. The increase in transmission with the increasing pulse energy, as well as with an increase in the number of pulses used for the formation of a single crater, is shown. The experimental results of ARM transmission of GaSe are in qualitative agreement with the simulation results based on the measured profiles and morphology of the ARM structures.

Influences of sand concentration and flow velocity on hydro-abrasive erosion behaviors of HVOF sprayed Cr3C2–NiCr and WC–Cr3C2–Ni coatings

Improving the hydro-abrasive erosion (HAE) resistance of the existing flow-handling components has been a matter of continuous effort for the hydraulic machineries. In current work, the effects of sand concentrations (SC) and flow velocities (FV) on HAE behaviors of high-velocity oxygen-fuel (HVOF) sprayed carbide-based cermet (i.e. Cr3C2–NiCr and WC–Cr3C2–Ni) coatings were studied using a rotating disk rig facility. The obtained results revealed that the WC–Cr3C2–Ni coating possessed lower porosity value, higher hardness (H) and elastic modulus (E) values, superior HAE resistances, and appeared less influenced by SC as well as FV compared with the Cr3C2–NiCr coating. Higher SC and FV caused more severe HAE degradations for both carbide-based cermet coatings, while FV had a greater influence on HAE resistances for both coatings than SC. With the increase of the SC and FV, the Cr3C2–NiCr coating experienced the HAE process of the isolation of hard phase grains as well as the scouring, the connection of micro-cracks as well as severe plastic deformations, and the crater formation as well as deep scour marks, while the HAE process of the WC–Cr3C2–Ni coating mainly included the micro-cracks, the erosion pits, and the scour marks.

Momentum Enhancement during Kinetic Impacts in the Low-intermediate-strength Regime: Benchmarking and Validation of Impact Shock Physics Codes

In 2022 September, the DART spacecraft (NASA’s contribution to the Asteroid Impact & Deflection Assessment (AIDA) collaboration) will impact the asteroid Dimorphos, the secondary in the Didymos system. The crater formation and material ejection will affect the orbital period. In 2027, Hera (ESA’s contribution to AIDA) will investigate the system, observe the crater caused by DART, and characterize Dimorphos. Before Hera’s arrival, the target properties will not be well-constrained. The relationships between observed orbital change and specific target properties are not unique, but Hera’s observations will add additional constraints for the analysis of the impact event, which will narrow the range of feasible target properties. In this study, we use three different shock physics codes to simulate momentum transfer from impactor to target and investigate the agreement between the results from the codes for well-defined target materials. In contrast to previous studies, care is taken to use consistent crushing behavior (e.g., distension as a function of pressure) for a given porosity for all codes. First, we validate the codes against impact experiments into a regolith simulant. Second, we benchmark the codes at the DART impact scale for a range of target material parameters (10%–50% porosity, 1.4–100 kPa cohesion). Aligning the crushing behavior improves the consistency of the derived momentum enhancement between the three codes to within +/−5% for most materials used. Based on the derived mass–velocity distributions from all three codes, we derive scaling parameters that can be used for studies of the ejecta curtain.

Femtosecond Laser Fabrication and Ultrafast Dynamics Study on FTO Film

Transparent conductive oxides (TCO) are widely used in optoelectronic devices due to their high visible light transmittance and high electrical conductivity. Fabricating micro-nano structures on TCO films with femtosecond lasers can further enhance their optoelectronic properties. However, most of the existing researches on femtosecond laser processing of TCO films focus on materials such as indium tin oxide (ITO) and ZnO, and the research on fluorine-doped tin oxide (FTO) is still insufficient. In this paper, the ablation rules of FTO film irradiated by femtosecond laser is studied in detail. When the fluence is reduced to 1/e2 of the peak value as the radius of the laser spot, the ablation threshold measured by epitaxy method is 1.27 J/cm2. The experiment explores the ablation morphology of FTO film irradiated by single femtosecond laser pulse. When the laser fluence is 2.8-8.3 J/cm2, a bowl-shaped micro-crater is ablated, and when the laser fluence is 9.6-23.4 J/cm2, a secondary crater with a vertical inner wall and a flat bottom generates in the center of the ablated bowl-shaped crater. The pump-probe technique was used to study the ultrafast dynamics of the femtosecond laser interaction with FTO film, and we found that the phase explosion was responsible for the bowl-shaped crater formation.

Study on parameter analysis and damage mechanism of water jet combined with mechanical cutter head breaking concrete

For concrete buildings, the tasks of maintenance and reconstruction will rapidly increase with time, and concrete breaking is one of the important technical processes. In this study, it proposed the water jet combined with mechanical cutter head breaking concrete technology, which has advantages in efficiency, safety and quality compared with mechanical breaking concrete buildings. To reveal parameter influence rules and damage mechanism of water jet combined with mechanical cutter head breaking concrete, it investigated the experiment of water jet combined with mechanical cutter head breaking concrete under different water jet parameters by orthogonal experiment and numerical simulation. Within the range of water jet parameters studied in this experiment, the order of sensitive factors of water jet parameters is the diameter of the nozzle > the impact time > the water pressure > the jet target distance. Compared with the mechanical breaking methods, the working pressure of the mechanical cutter head can reduce by 10.00%–36.67% in water jet combined with mechanical cutter head. The optimal water jet parameter combination is the 360 MPa of water pressure, the 6 mm of jet target distance, the 80 s of impact time, and the 0.5 mm of diameter of the nozzle. Moreover, based on the smooth particle hydrodynamics (SPH) method, it established the numerical model of water jet combined with mechanical cutter head breaking concrete, verified by the crack propagation state inside the concrete based on computer tomography (CT). The results demonstrated that at the initial stage of water jet impacting concrete, compressive stress and shear stress caused craters formation; at the stage of continuous impact of water jet, cracks formation in concrete was mainly caused by tensile stress; at the initial stage of mechanical cutter head pressing concrete, concrete was mainly subjected to compressive stress and shear stress resulting in craters development; at the stage of mechanical cutter head penetrating concrete, cracks development was mainly caused by compressive stress and shear stress. The results can provide theoretical supports for the water jet combined with mechanical cutter head breaking concrete buildings.

Effects of Flow Velocity and Sand Concentration on Hydro-Abrasive Erosion Behavior of HVOF-Sprayed WC-Cr3C2-Ni Coating in 3.5 wt.% NaCl Aqueous Solution

To explore the hydro-abrasive erosion (HAE) behaviors of a high-velocity oxygen fuel (HVOF)-sprayed WC-Cr3C2-Ni coating in 3.5 wt.% NaCl aqueous solution, various flow velocities (FVs) and sand concentrations (SCs) were designed using a rotating disk rig facility. In comparison with 1Cr18Ni9Ti stainless steel, the WC-Cr3C2-Ni coating possessed higher hardness (H) and elastic modulus (E) values, worse anticorrosion properties, and superior HAE resistances in 3.5 wt.% NaCl aqueous solution. Higher FVs and SCs caused more severe HAE degradations for both the WC-Cr3C2-Ni coating and the 1Cr18Ni9Ti stainless steel, while FV had a greater influence on HAE resistances than SC. With an increase in the FV and SC, uncontinuous corrosion product films and erosion pits, the micro-cutting of the soft binder matrix and the fracturing of hard-phase grains, and crater formation and coating spalling were addressed as the HAE failure mechanisms in the 3.5 wt.% NaCl aqueous solution of the WC-Cr3C2-Ni coating.

Cavitation–Silt Erosion Behavior and Failure Mechanism of an HVOF-Sprayed WC-Cr3C2-Ni Coating for Offshore Hydraulic Machinery

WC-Cr3C2-Ni coatings are a vital class of hard ceramic/cermet coatings with potential applications as wear-resistant materials. However, their erosion wear behavior in 3.5 wt.% sodium chloride medium (SCM) remains largely unexplored. The present study investigated the cavitation–silt erosion (CSE) behavior in 3.5 wt.% SCM of WC-Cr3C2-Ni coatings sprayed with high-velocity oxygen–fuel (HVOF) under different flow velocities (FVs) and sand concentrations (SCs). Comparing the WC-Cr3C2-Ni coating with the 1Cr18Ni9Ti stainless steel, the first possessed superior CSE resistance in 3.5 wt.% SCM in a full range of FV and SC. Meanwhile, the coating appeared more influenced by FV and less influenced by SC, which was indicated by the fact that the amplification of VLR value (377.1%) when the FV ranged from 23.4 to 41.9 m·s−1 was larger than that (129.8%) when the SC increased from 10 kg·m−3 to 35 kg·m−3. With increasing FV and SC, the CSE process of the WC-Cr3C2-Ni coating in 3.5 wt.% SCM mainly included the discontinuous corrosion product films, erosion pits, fracturing of hard-phase grains, and micro-cutting of soft binder matrix, as well as crater formation and coating spalling.