The accelerated degradation of energy infrastructure components functioning in an extreme service environment is one of the key issues for long-term reliability and safety. Carbide-reinforced thermal spray coatings are widely used as protective solutions; nevertheless, their behavior under combined thermal, erosive, and corrosive stresses is of high variability, and the mechanisms of degradation are not yet fully understood. Key unsolved scientific issues include the interplay between erosion and oxidation across a range of temperature regimes, why conflicting erosion-corrosion (E-C) trends are often reported for similar coating systems, and what microstructural features fundamentally control coating stability at high temperatures. This critical review is a synthesis of recent advances in understanding the high-temperature E-C behavior of carbide-reinforced coatings by systematically examining deformation mechanisms, including particle-impact erosion, oxide-scale formation/spallation, carbide dissolution, and interface-controlled failure. Further, emphasis is placed on the roles of carbide chemistry, binder composition, microstructural integrity, and thermal spray processing routes in determining regime-dependent performance. The shortcomings of current methods for quantifying E-C synergy are critically reviewed, and mechanistic models are proposed to reconcile the varying results in the published literature. Based on this synthesis, key research gaps are identified, including the need to design oxidation-resistant binders, improve control of carbide stability during deposition, conduct long-term performance assessment at service-relevant temperatures, and develop predictive models of E-C regimes. Overall, this review provides a roadmap for the rational design of next-generation protective coatings for metals and alloys subjected to extreme high-temperature environments.

Understanding erosion–corrosion mechanisms in selective laser-melted (SLM) Ti-6Al-4V is essential for optimizing component durability in demanding sectors such as oil and gas, hydropower, and offshore engineering, where slurry-induced degradation prevails. Nevertheless, it is challenging to experimentally evaluate slurry erosion–corrosion over a wide range of SLM processing parameters and various slurry erosion–corrosion operating conditions. The adaptive neuro-fuzzy inference system (ANFIS) offers a robust computational approach for modeling complex systems with independent variables, making it well suited for this investigation. This study aims to assess the efficacy of ANFIS in predicting the mass loss of as-built SLM-processed Ti-6Al-4V under slurry erosion–corrosion conditions, with a focus on the synergistic effects of impact angle and erodent mass in both saline and pure water environments, validated against empirical data. The quantitative analysis reveals that erodent mass is the dominant factor influencing mass loss, followed by impact angles. Notably, the combined effect of erodent mass and impact angles in saline environments (e.g., sea water) exacerbates material loss by approximately 16% compared to pure water, highlighting the critical role of electrochemical corrosion in synergy with mechanical erosion. The results demonstrate that the ANFIS model accurately simulates the degradation behavior of SLM-processed Ti-6Al-4V subjected to water–silica slurry impacts within the experimental parameter space; however, predictive generalization beyond these conditions should be interpreted carefully due to validation constraint.

Purpose The purpose of this study to characterize the erosion–corrosion characteristics of a 90° horizontal elbow under different sand content conditions. This study aims to reveal the effect of sand content in liquid–solid two-phase flow on the erosion–corrosion of the elbow and to provide theoretical guidance for the protection against erosion–corrosion of elbows under such conditions. Design/methodology/approach A pipe flow test device was used to study the effect of sand content on the erosion–corrosion of a 90° horizontal elbow. The weight loss method was used to quantify the erosion–corrosion rates at different locations of the elbow under different sand content conditions. Electrochemical tests were used to characterize the electrochemical properties of different locations on the elbow, and surface analysis techniques were used to examine the erosion–corrosion morphology of the elbow. Findings This study reveals that the erosion–corrosion rates, electrochemical characteristics and surface morphologies on the inner surface of the 90° horizontal elbow are significantly influenced by sand content. As the sand content increases from 0% to 1.25%, the arc radius of the electrochemical impedance spectrum noticeably decreases, while the erosion–corrosion rates and maximum pit depths increase substantially. The surface morphology transitions from sheet-like structures to more severe pit and groove formations. When the sand content increases from 1.25% to 2.5%, the reduction in the arc radius is minor, and the changes in erosion–corrosion rates and maximum pit depths are less pronounced, though still present. Surface morphologies continue to develop in greater depth, with an increase in the number of pits and grooves. In liquid–solid two-phase flow, the areas of severe erosion–corrosion are mainly at the bottom of the horizontal elbow and on the outside of the elbow outlet. Overall, this study highlights that sand content is a significant factor in accelerating erosion–corrosion, with higher sand concentrations leading to more extensive damage on the elbow surface. Originality/value This study investigates how sand content affects the erosion–corrosion of a 90° horizontal elbow. It characterizes the erosion–corrosion rates, electrochemical properties and surface morphologies at various locations of the elbow, revealing the underlying mechanisms by which sand content influences its erosion–corrosion behavior.

ABSTRACT Boiler steels operating in high‐temperature and aggressive environments face significant degradation due to erosion–corrosion. This review explores the development and performance of hybrid coatings reinforced with ceramics and industrial waste materials, particularly those applied by high‐velocity oxy‐fuel (HVOF) thermal spray technology. By combining the hardness and thermal stability of ceramics with the sustainability and cost‐effectiveness of industrial wastes like fly ash, these hybrid coatings significantly enhance wear, oxidation, and corrosion resistance. The paper discusses feedstock engineering, microstructural characteristics, high‐temperature phase stability, erosion–corrosion synergy, and case studies in industrial applications. Despite notable improvements, challenges such as optimizing carbide content, improving fracture toughness, and ensuring coating density persist. Future prospects include the use of nanostructured and high‐entropy materials, advanced spray techniques, and AI‐assisted design tools, positioning hybrid HVOF coatings as a promising solution for enhancing the durability of boiler steels and other critical components in harsh operating conditions.

This paper addresses the problem of accelerated corrosion–erosion degradation of exhaust valves in marine diesel engines, caused by the combined effects of high temperature, aggressive sulfur compounds, and abrasive ash particles in combustion products. The main objective was to develop and validate a reproducible laboratory method that enables accelerated simulation of real operating conditions and quantitative assessment of the influence of individual factors on overall wear. A dedicated corrosion–erosion test chamber was designed to ensure precise control of sample surface temperature (650–800 °C), sulfur oxide (SOₓ) concentration, solid particle content, and other environmental parameters. The test specimens were exhaust valves from a 6ChN 18/22 engine, including both uncoated samples and those with heat-resistant protective coatings. To optimize testing and maximize information yield, a fractional factorial experimental design (2⁵⁻¹) was applied, enabling systematic evaluation of five key variables. After 100-hour test cycles, a comprehensive analysis was carried out, including measurements of wear rate, microcrack depth, mass loss, and microhardness changes. Analysis of variance (ANOVA) showed that surface temperature and SOₓ concentration exert the greatest influence on wear, with a pronounced synergistic interaction between SOₓ and solid particles. The experiments confirmed that fuel additives reduce chemical corrosion by 30–35 %, while protective coatings decrease erosive wear by 20–25 %. Validation of the developed method against field data demonstrated good agreement, with deviations within 10–15 %. The proposed methodology serves as an effective tool for predicting the service life of exhaust valves and justifying the selection of protective measures in marine engine design and shipbuilding practice.

This study evaluated the physical and chemical changes that turbine blades are exposed to under operating conditions and their effects on the material. Within the scope of the study, the amount of corrosion and wear that occurred during the durability/operational life of a turbine blade and its coating used for 25 years in a Thermal Power Plant and an original turbine blade made of the same material that has never been used were comparatively examined. This research contains important findings in evaluating the suitability of the existing material and coating for longer life of turbine blades and obtaining ideas for changes to be made to the coating in terms of resistance to physical and chemical conditions. The turbine blade examined in the study was determined to be coated with Co-based material (containing Cr, Mo, Ni, Mn) using the thermal metal spray coating method. AgCuZn-based bond coating was applied to the coating and the substrate. After 25 years of service with an average energy production of 69,466,700 MWh, the turbine blade was removed from the turbine and examined for corrosion and erosion damage analyses. In the experimental study, chemical and dimensional measurements, optical microscopy, SEM, and EDS measurements were carried out due to the metallographic preparation of the samples. XRD performed structural analysis, and hardness testing was used to determine the mechanical properties and life of the samples. As a result of the investigations, it was determined that the turbine blade was subjected to both corrosion and erosion and corrosive erosion, the coating on the surface was completely worn locally, and there was a cross-sectional reduction due to wear (corrosive and erosive) at the blade tips. The coated parts were more resistant to erosive and corrosive effects. The transition zone between the base material and the coating starting point was very effective in coating wear. It has been observed that corrosion and erosion cause abrasion together.

Limitations of GFRP wrapping revealed by Erosion–Corrosion and sulfide stress cracking in Sour-Gas Environments: Experimental and numerical simulation perspectives

Effect of the shot peening finishing on cavitation erosion and corrosion resistance of DMLS manufactured 17-4PH steel

Hybrid polishing of mm-TSVs using laser cavitation-driven micro-abrasive erosion and laser-enhanced electrochemical corrosion

The term corrosion originates from the Latin word “corrosio”, meaning erosion or degradation. Metal corrosion refers to their deterioration and becoming unserviceable as a result of chemical, electrochemical, or biochemical effects. Due to the reduction of the free energy of a construction material, metals exhibit thermodynamic instability. In essence, corrosion can be defined as the destruction of metals and alloys under the influence of the external environment. In some metals, the degradation process occurs not only on the surface but also within the material. This leads to the disruption of the crystal lattice structure and results in the loss of intrinsic properties. When impurities are abundant within the metal, galvanic couples may form on the surface, leading to localized points of attack and the development of pitting corrosion, which accelerates metal degradation. The economic damage caused by corrosion across different countries can be illustrated by several examples. According to Le Metayer, in 1953 the economic loss to Norway due to corrosion amounted to 180 million marks. In 1964, damages to France’s marine structures reached 80 million francs. Every year, biological corrosion results in a loss of 25 million dollars in Australia and 5 million dollars in New Zealand. In the United States, biofouling in the shipping industry causes an annual loss of 10 million dollars, while sulfate-reducing bacteria in underground pipelines cause damages estimated between 500–2000 million dollars annually. To protect the famous Eiffel Tower from corrosion, 70 tons of special paint and varnish are applied every three years. Generally, the surfaces of metals in their normal state and after corrosion differ significantly. However, certain types of corrosion are invisible to the naked eye. This phenomenon, known as intergranular corrosion (metal embrittlement), occurs due to the disruption of the crystal lattice structure of metals. Corrosion of metals is observed under various environmental conditions such as water, atmosphere, soil, acidic, and alkaline media. The electrochemical corrosion process occurs as a result of the formation of a double electric layer at the metal–environment interface. In some cases, chemical effects are accompanied by physical degradation, which is termed erosion–corrosion or fretting–corrosion. In the case of iron and its alloys, rusting occurs as hydrated corrosion products are formed from oxides. Non-ferrous metals also corrode, although they do not form rust. During the design and construction of pipelines, the protection of pipeline structures and foundations of pipes from environmental impacts must be ensured. Keywords: pipeline, metal, environment, protective coating, corrosion

With the progress of human civilization and technology, the focus on civil engineering materials has shifted toward modern concrete materials. These materials are characterized by the incorporation of various admixtures and fibers. Therefore, it is essential to study their durability under diverse environmental conditions. Firstly, an experimental method is designed to investigate the combined effects of freeze–thaw cycles, carbonation erosion, and sulfate corrosion on concrete durability. Then, models for concrete deterioration are constructed based on the water–binder ratio, fly ash content, polypropylene fiber content, sulfate solution concentration, and compressive strength of concrete, which can reveal the interplays of freeze–thaw cycles, carbonation, and sulfate conditions. Meanwhile, an index-oriented adaptive differential evolution (IOADE) algorithm is proposed to obtain the optimal parameters for the deterioration models. Finally, data experiments demonstrate the reasonableness and efficacy of the proposed models.

The engineering applicability of alkali-activated mortar (AAM) is limited by high shrinkage and fast setting time. In this study, the shrinkage performance of AAM was regulated by adding desulfurization gypsum (DG), and the effects of DG content on its workability, corrosion resistance, and mechanical properties were systematically investigated. The test included fluidity, setting time, compressive strength, drying shrinkage, water erosion resistance, and sulfate erosion resistance and was combined with microscopic analysis to reveal its phase composition and micro-morphology. The results show that DG can significantly prolong the setting time and reduce the drying shrinkage. With a DG content of 10%, alkali-activated materials exhibited a setting time similar to that of OPC, and the 56-d drying shrinkage of the AAM was reduced by 20.2%. However, the fluidity, water erosion resistance, and sulfate resistance decreased with an increase in DG content. When the DG content was 10%, the fluidity of the AAM reached 126 mm, and its setting time was equivalent to that of OPC. The mechanical properties showed a trend of increasing first and then decreasing. The optimum was reached when the DG content was 6%. The 28-d compressive strength of AAM-6 was 63.25 MPa, and after 60 days of water erosion and sulfate corrosion its residual strength was still higher than that of OPC in the same environment. Microscopic analysis showed that DG promoted the formation of ettringite, which filled pores with age and formed a dense structure, thereby improving mechanical properties and inhibiting shrinkage. This study enhances the engineering applicability of AAM while enabling high-value utilization of industrial solid waste for sustainable construction materials.

Abstract: Tungsten carbide based spray coatings are widely used in industry for application requiring abrasion, sliding, fretting and erosion corrosion resistance. High velocity oxy-fuel (HVOF) flame spraying was used for producing high quality carbide composite coatings. In this study, a WC-CoCr and WC-CoCrNi powders were thermal sprayed using a HVOF process. The spray parameters were varied in order to investigate their influence on microstructure and mechanical properties of coatings. It is possible to produce homogeneous coating by controlling the flame temperature, the velocity of the gun transverse, the powder feed rate and the nature of the powders. The mechanical properties and the porosity rate could be optimized in order to improve the functional properties.

Failure mechanism of sulfur transport jacketed pipeline induced by the combined effects of steam erosion and wet sulfur corrosion

The role of rotary liquid-solid two-phase flow in the synergistic behavior between sand erosion and electrochemical corrosion of Ni2FeCrMo0.2 alloy in marine environment

Duplex stainless steel (DSS) 2205 is widely used in oil and gas infrastructure for its excellent mechanical strength and corrosion resistance; however, erosive flow conditions can severely degrade its surface and compromise performance. This study employs the Taguchi design of experiments to optimize corrosion resistance of eroded DSS 2205 in simulated oil and gas environments. Slurry erosion tests followed by potentiodynamic polarization revealed that optimized conditions—150 m/s impact velocity, 5 g/min erodent feed rate, and a 90° impingement angle—reduced the corrosion rate by up to 50%. Analysis of variance (ANOVA) confirmed the statistical significance of these parameters. Surface analysis using SEM and profilometry supported the electrochemical findings by showing reduced erosion damage under optimized conditions. The practical significance of this work lies in its data-driven framework for mitigating erosion–corrosion synergy, offering valuable guidance for enhancing the durability and service life of DSS components in aggressive oil and gas environments.

In high-pressure gas field exploitation, wellhead fluids contain not only gas phases but also liquid water and solid particles; thus, the valve seat and core of high-pressure throttle valves are extremely susceptible to failure caused by complex fluid erosion, which seriously threatens gas field production and human safety. The historical development of erosion theory is surveyed initially, followed by a summary of current erosion theories, highlighting the limitations of single-theory formulations in modeling complex erosion processes. The erosion research framework for solid-laden fluids is subsequently described, comprising governing equations, turbulence models, calculation methods, particle behavior models, and erosion models. Besides, structural factors, flow conditions, solid particle properties, substrate properties, and interaction between erosion wear and corrosion influencing throttle valve erosion wear are summarized, clarifying the mechanisms and recent investigation findings of various factors. Following that, two research methods for erosion wear-experimental and numerical simulation methods, are introduced comprehensively. Finally, trends of future research on erosion wear in high-pressure throttle valves are predicted.

Nickel aluminum bronze (NAB) and manganese aluminum bronze (MAB) are widely used in propulsion and seawater handling systems in naval platforms due to their attractive combination of mechanical strength, toughness, and very low susceptibility to marine corrosion. Nevertheless, it is well known that they can suffer from selective phase corrosion and erosion–corrosion, primarily caused by cavitation and sand erosion. Both alloys have a multiphase microstructure that governs their mechanical and chemical behavior. The tribocorrosion behavior of cast NAB and MAB alloys was studied in artificial seawater to analyze the effect on microstructure. The microstructure and nanohardness were evaluated and correlated with tribocorrosion test results conducted under two different loads (10 and 40 N) in a unidirectional sliding mode using a 1 M NaCl solution as the electrolyte. A significant increase in the corrosion rate due to the wear effect was observed in both alloys. MAB exhibited a slightly better tribocorrosion performance than NAB, which was attributed to significant differences in the shape, distribution, and size of the intermetallic kappa phases—rich in iron, aluminum, and nickel—within the microstructure. Pitting corrosion was observed in NAB, while selective corrosion of kappa phases occurred in MAB, highlighting the role of the protective layer in the tribocorrosion behavior of both alloys. These findings were supported by post-test solution analysis using ICP-AES and corrosion product characterization by EDX. A synergistic effect between wear and corrosion was confirmed for both alloys, as erosion removes the protective layer, exposing fresh material to continuous friction and favoring a progressive material loss over time. The practical impact of this study lies in improving the control and design of highly alloyed bronze microstructures under in-service corrosion–erosion conditions.

The passivation zone refers to the area where the protective passivation film is formed on the metal surface and is stable. To assess the distribution of high-risk regions of metal erosion-corrosion in passivation zones at normal temperature, a Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) model was created to examine metal erosion-corrosion (E-C) behavior in these zones. By changing the mass flow rate, particle size, and particle velocity of inlet particles, the erosion-corrosion loss under multi-attribute coupling was calculated. The results of the multi-attribute coupling of particles show that when the inlet velocity is large, the influence of different particle mass flow rates and sizes on the maximum erosion-corrosion loss is obvious. When the inlet velocity is low, an increase in particle mass flow rate and particle size will lead to a decrease in the erosion-corrosion growth rate and erosion-corrosion loss, respectively, within a certain range. When the particle mass flow rate is larger or the particle size is larger, the erosion-corrosion loss of the elbow is more obviously affected by the change in inlet velocity. Finally, the correlation degrees between the inlet velocity, particle mass flow rate, particle size and the maximum corrosion and wear loss were quantified through the grey correlation degree analysis method.

Enhanced ultrasonic cavitation erosion and corrosion resistances of carbide-based composite coatings by graphene☆