Erosion-corrosion Environments Research Articles

Erosion-Corrosion Behavior of Electroless Ni–P Coating on M2052 Alloy in Artificial Seawater

M2052 damping alloy has good shock absorption and noise reduction ability, but the corrosion resistance and wear resistance are insufficient. In this study, a high phosphorus amorphous Ni–P coating with a thickness of about 22.1 µm was successfully deposited on the M2052 substrate by electroless plating. The wear experiments show that the main wear mechanism of Ni–P coating is adhesive wear, while the main wear mechanism of M2052 substrate is abrasive wear and corrosion wear. Compared with M2052 substrate, the electroless plating sample has a lower corrosion current and higher corrosion potential, and the corrosion resistance is greatly improved. In the erosion-corrosion environment, the corrosion rate of the uncoated sample is about 5 times that of the coated sample. However, the damage of Ni–P coating under the same environment corroded slightly, which effectively impedes the erosion of sediment flow and the corrosion of artificial seawater.

Effects of pre-filmed FeCO3 on flow-induced corrosion and erosion-corrosion in the absence and presence of corrosion inhibitor at 60 °C

In CO2 environments, an increase in the temperature can influence carbon steel flow-induced corrosion (FIC) and erosion-corrosion (EC) degradation processes. Increasing temperature typically results in the acceleration of electrochemical degradation mechanisms in the absence of protective corrosion product layers. Furthermore, the presence of sand in corrosive process fluids could aggravate the service conditions. Although protective iron carbonate (FeCO3) film or/and corrosion inhibitors are capable of suppressing corrosion in CO2-containing environments typical of oil and gas production, their ability to suppress degradation and their associated mechanisms in erosion-corrosion environments is less understood. This work focuses on understanding the ability of FeCO3 to protect the steel surface in the absence and presence of corrosion inhibitor and their interactions in flow-induced and erosion-corrosion systems at 60 °C. The effect of the temperature increase is investigated based on results obtained in a previous study performed at 25 °C. FeCO3 filmed carbon steel specimens were developed using an autoclave at 60 °C, pH 6.6 and 30 bar in a 1.5 wt% NaCl CO2-saturated solution over 48 h. The FeCO3 covered specimens were evaluated in FIC and EC environments at 60 °C and a flow velocity of 15 m/s in the presence and absence of 1000 mg/L sand and 100 ppm of a commercially available corrosion inhibitor. Results indicate that the sole presence of an FeCO3 layer is not sufficient to retard the corrosive process of carbon steel at 60 °C under EC conditions. However, the commercial corrosion inhibitor was observed to worked synergistically with the FeCO3 layer to reduce the corrosion degradation component in both the presence and absence of sand particles. The erosion component is also reduced in erosion-corrosion environments as a result of the combined presence of FeCO3 and corrosion inhibitor.

Evaluation of high shear inhibitor performance in CO2-containing flow-induced corrosion and erosion-corrosion environments in the presence and absence of iron carbonate films

Carbon steel pipeline degradation occurs as a result of erosion-corrosion during oil and gas production. Sand particles contribute to this effect when they are present in conjunction with a high flow velocity. In carbon dioxide (CO2) environments, and under certain conditions, the corrosion rate of the steel can be reduced by the formation of a protective iron carbonate (FeCO3) layer. This work assesses the ability of FeCO3 to protect the underlying steel in flow-induced corrosion and erosion-corrosion environments. Autoclave tests are performed at 60 °C and 100 bar in a 1 wt%NaCl CO2-saturated solution for a duration of 48 h to develop 60 µm thick FeCO3 films. The film-covered samples were then transferred into a submerged impinging jet (SIJ) apparatus to assess their ability to resist both flow-induced corrosion and erosion-corrosion environments at 25 °C and a flow velocity of 15 m/s (both with and without 1000 mg/L sand). Tests were also conducted in the presence of a commercially available corrosion inhibitor to evaluate the interaction. Results indicate that the FeCO3 layer is able to considerably suppress corrosion of the carbon steel substrate. Experiments in the presence of both the FeCO3 film and corrosion inhibitor demonstrated that there is a notable synergistic effect between these two components in providing resistance to erosion-corrosion.

Effects of shear stress on the erosion‐corrosion behaviour of X-65 carbon steel: A combined mass-loss and profilometry study

A combined mass-loss and profilometry techniques was undertaken with the goal of understanding the role of high shear stress on the erosion‐corrosion behaviour of X65 carbon steel in a submerged impingement jet (SIJ) system. Computational fluid dynamics (CFD) enabled an accurate prediction of a range of shear stresses (80, 280, 570Pa) and particle tracking (0, 200, 500mg/L) across the sample surface with inhibitor concentration (0, 100ppm). The results demonstrated the suitability of combining mass–loss and surface profilometry techniques for quantifying and predicting general and localized corrosion of X65 pipeline material in an erosion–corrosion environment.

Comparative study of erosion–corrosion performance on a range of stainless steels

Erosion–corrosion is one of the most severe types of material deterioration that occur in hydraulic machinery. Corrosion resistant alloys perform well in some marine applications. These materials do have their limitations, though, and for this reason a comparison of their performances is significant. This study focuses on the assessment of the relative behaviour of four different types of stainless steel (UNS S31600, UNS S32760, UNS S42000, and UNS S17400) in erosion–corrosion environments. The study was expanded to include a carbon steel (UNS G10400). Test pieces have been investigated in a submerged jet impingement apparatus in 3.5% NaCl solution with suspended solid particles at temperatures of 30–35°C. In situ corrosion monitoring was also undertaken and the influence of the application of cathodic protection was studied. This facilitated assessment of the relative roles of erosion, corrosion and synergy on the overall degradation processes. A variety of examination techniques were utilised (i.e. mass loss, surface profiling, microscopy) in order to obtain detailed information on those different modes of attack. Differences between stainless steels and carbon steel were observed and the superduplex stainless steel exhibited the best performance of the four types of stainless steel investigated herein.

Evaluating Inhibitor Performance in CO2-Saturated Erosion-Corrosion Environments

Over the last decade, significant advances in chemical inhibition have enabled operators to use carbon steel pipework in oil and gas facilities where sand production is a concern. The ability of th...

Assessing the influence of shear stress and particle impingement on inhibitor efficiency through the application of in-situ electrochemistry in a CO2-saturated environment

An investigation was conducted to assess the performance of a commercially available high shear carbon dioxide (CO2) corrosion inhibitor in a series of flow-induced corrosion and erosion–corrosion environments. The purpose of the study was to understand the role that high shear stress and sand particle impingement play in influencing the in-situ corrosion rate of API 5L X65 carbon steel in blank and inhibited conditions. Tests were conducted at 45°C in CO2-saturated conditions using a rotating cylinder electrode (RCE) for low shear stress tests (18–260Pa) and a submerged impinging jet (SIJ) for high shear environments (104–740Pa). The inhibitor was studied at concentrations of 0, 25, 50, 75 and 100ppm. The application of computational fluid dynamics to model the SIJ and the use of ring shaped samples allowed for an accurate prediction of shear stress across the specimen surface that could be correlated with in-situ corrosion rate and inhibitor efficiency over a range of concentrations. The incorporation of 500mg/L of sand to the system helped to quantify the increase of the in-situ corrosion rate due to the impingement of the particles. All corrosion rates were determined through the application of linear polarization measurements throughout the duration of the test. Post-test analysis of the material degradation mechanisms was examined using scanning electron microscopy (SEM).

Empirical Prediction of Carbon-Steel Degradation Rates on an Offshore Oil and Gas Facility: Predicting CO2 Erosion-Corrosion Pipeline Failures Before They Occur

Summary Various sections of carbon-steel pipework removed from an offshore facility were found to have experienced severe degradation, partly attributed to an insufficient inhibitor dose rate, as discussed in a previous case study (Hu et al. 2011b). An investigation was conducted to compare the predictive capability of an empirical model generated with data from a submerged-impinging-jet laboratory apparatus. The model was assessed in its ability to determine the rate of thickness loss for carbon-steel pipework subjected to a CO2-containing erosion-corrosion environment, reviewing to what extent the prediction agrees with inspection data. The investigation considers whether the developed tool could have predicted pipework failures on the facility, comparing it with the degradation rate calculated from a leak that occurred within the past 2 years. The program of experiments set out to create a means of prediction with the material-loss data from submerged-impinging-jet tests over a range of conditions replicating those within the line. Information pertaining to the temperature, production rate, and sand loading was collated for the offshore facility. These data were used along with mass-loss results to predict the degradation rate on the asset as a function of time over a 5-year period. This in turn was used to predict the total thickness loss of the pipework wall as a function of time. Consideration was also given to the current use of inhibition (10 ppm Inhibitor A) as well as the predicted thickness losses as a function of time had a candidate inhibitor been used instead (50 ppm Inhibitor B). Limitations of the model are presented, along with suggestions for ways to develop the model further.

Determination of particle impacts and impact energy in the erosion of X65 carbon steel using acoustic emission technique

An in-situ acoustic emission (AE) monitoring technique has been implemented in a submerged jet impingement (SIJ) system in an effort to investigate the effect of sand particle impact on the degradation mechanism of X65 carbon steel pipeline material in erosion conditions.A detailed analysis of the acoustic events' count rate enabled the number of impacts per second to be quantified for a range of flow velocities (7, 10, 15m/s) and solid loadings (0, 50, 200, 500mg/L) in a nitrogen-saturated solution at 50°C. The number of impacts obtained from acoustic signals showed a strong agreement with theoretical prediction for flow velocities 7 and 10m/s. A deviation between practical readings and theory is observed for flow velocity of 15m/s which may be due to error from detected emissions of multiple rebounded particles.Computational fluid dynamics (CFD) was used in conjunction with particle tracking to model the impingement system and predict the velocity and impact angle distribution on the surface of the sample. Data was used to predict the kinetic energy of the impacts and was correlated with the measured AE energy and material loss from gravimetric analysis. The results demonstrate that AE is a useful technique for quantifying and predicting the erosion damage of X65 pipeline material in an erosion–corrosion environment.

The influence of high shear and sand impingement on preferential weld corrosion of carbon steel pipework in CO2-saturated environments

Preferential weld corrosion (PWC) has proved problematic for the oil and gas industry for a number of years. Although the effect of high flow rates on PWC in inhibited CO2-saturated solutions has been studied by authors, the consideration of a higher, localised turbulence over the weld material and the implications this has on PWC appears minimal. This work considers this very effect, along with developing an understanding of the threats posed to weld integrity by sand particle presence in the process fluid using a submerged impinging jet (SIJ) apparatus.Experiments were conducted using a commercially available film-forming oilfield corrosion inhibitor which was evaluated in both flow-induced corrosion and erosion–corrosion environments in its ability to control PWC. The SIJ setup allowed control over the individual flow velocities at each nozzle, meaning shear stress could be intensified over the 1% Ni–0.25% Mo weld material to simulate localised turbulence at the sample surface. Galvanic current and mixed potential measurements were performed to ascertain changes in galvanic interactions between the two materials. The work demonstrates that localised turbulence over internal weld beads and the presence of sand within oil and gas systems can influence PWC in certain environments.

Aspects of microstructure on the synergy and overall material loss of thermal spray coatings in erosion–corrosion environments

The influence of microstructure on the overall material loss in erosion–corrosion environments is presented for WC–Co–Cr coatings applied by (i) High Velocity Oxy-Fuel (HVOF) and (ii) Super Detonation-Gun (D-Gun) processes. The study is focused on understanding the synergy effect (here defined as the enhancement of erosion due to corrosion effects) on material loss when two different microstructures are formed and also the influence of chemical composition of the coating. Experiments showed that HVOF coatings have a slightly lower corrosion resistance than the Super Detonation-Gun (D-Gun) coatings but higher overall erosion–corrosion resistance. It is important to point out that HVOF and Super D-Gun coating microstructures vary depending on parameters of application and therefore the results presented in this paper cannot be generalised. In this work a particular case is presented to establish a link between the coating composition, microstructure and erosion–corrosion performance for WC–Co–Cr coatings when different microstructures are formed.

Corrosion and synergy in a WC [sbnd]Co [sbnd]Cr HVOF thermal spray coating—understanding their role in erosion–corrosion degradation

The material degradation of a high velocity oxy-fuel (HVOF) WC Co Cr thermal spray coating is addressed in this paper focusing on the effect of corrosion and the degradation caused by the interaction between corrosion and erosion (synergy) on the overall material loss in erosion–corrosion environments. The mechanical and electrochemical components, which contribute to degradation are isolated and evaluated using an experimental protocol comprising electrochemical techniques and scanning electron microscopy (SEM). Tests under erosion–corrosion conditions were performed in 3.5% NaCl solution with silica sand concentrations of 200, 500 and 1000 mg/l, at two temperatures (20 and 50 °C) and using an impingement velocity of 17 m/s. Austenitic (UNS S31603) and super duplex (UNS S32760) stainless steels were used as a reference and the performance of these three materials is presented. The results show that corrosion and corrosion–erosion interactions play an important role in the overall material degradation of the HVOF coating and that the dominance of each process is critically dependent on the environment. Some discussion of potential means of improving the coating durability is presented through consideration of the dominant processes in erosion–corrosion.

Alleviation of erosion–corrosion damage by liquid–sand impact through use of chemicals

Erosion–corrosion is a complex mechanism of material degradation resulting from interactions between electrochemical and mechanical processes. The consequences of erosion–corrosion are severe with economic penalties resulting from premature failure of components, increased downtime and increased maintenance costs. This paper assesses the efficiency of corrosion inhibitors in reducing material damage occurring as a consequence of erosion and corrosion processes under CO 2 saturated conditions. The inhibitor action is measured using gravimetric and electrochemical analysis. It has been demonstrated that the inhibitors, effective in reducing corrosion in static conditions, can also reduce material degradation in erosion–corrosion environments. Inhibitor action in this study is through adsorption on the metal surface and effective elimination of charge transfer. Through reduction of corrosion processes, the inhibitor facilitates the reduction of corrosion-related damage. There also appears to be a role of the inhibitor in affecting the mechanical impact damage.

Degradation mechanisms of Co-based alloy and WC metal–matrix composites for drilling tools offshore

The efficient performance of drilling tools in aqueous environments requires materials that can effectively resist excessive material loss due to the combined effects of erosion and corrosion. In this paper, the interactions between electrochemical corrosion and mechanical erosion have been assessed in liquid–solid slurry. The following materials were used: (a) a cobalt-based alloy which is currently used in the manufacture of oil tools, (b) a nickel-based composite coating with tungsten carbide and (c) a tungsten carbide copper-based solid cermet. The material degradation is assessed as a function of aqueous environment, sand loading and angle of impingement. Their degradation shows a distinctive electrochemical behaviour (corrosion) which has been shown to represent an important factor in the total degradation of these materials. The relative importance of corrosion and its synergistic effect when combined with aggressive erosion are quantified for different angles of impingement. The cobalt-based bit body material has a superior degradation resistance in the erosion–corrosion environments and although there is potential to use other materials to protect the areas of major damage near the nozzles in drilling tools. It is shown that simply replacing the materials with a harder cermet is not sufficient. The implications in terms of material performance and the potential protection from degradation is discussed in the paper.

Corrosion and erosion damage mechanisms during erosion–corrosion of WC–Co–Cr cermet coatings

Experiments were performed in order to evaluate the behaviour of WC–Co–Cr coatings applied by the Super D-Gun™ (Trademark of Praxair S.T. Technology) thermal spray process in erosion–corrosion environments. The experiments were performed in 3.5% NaCl with different silica sand loadings (200 and 500 mg/l). The results were compared with UNS S31603 and UNS S32760 stainless steels. Measurements of the total material loss showed that the coating applied by Super D-Gun presented higher resistance to erosion–corrosion compared to both stainless steel materials as expected. The connection between the erosion–corrosion behaviour of the Super D-Gun coating and the microstructure is assessed. Scanning electron microscopy (SEM) images enabled the different mechanisms of tribo-corrosion to be understood. With cermet materials there has been much discussion relating to the role of corrosion in removing the hard phase particles which can breach tribological performance. The corrosion rate ( i corr) of the coating was determined under erosion conditions and an evaluation of the influence of corrosion and synergistic processes on the erosion process was made using applied cathodic protection.

Looking beyond the millennium: critical issues in the evaluation of materials performance for resistance to erosive wear in corrosive conditions

Advances in the study of erosive wear in corrosive conditions have lead to improved understanding of the performance of materials in such conditions. Through mapping the materials degradation as a function of the main process parameters, the most favourable operating conditions may be identified. The maps, albeit still in their infancy, provide the basis for addressing materials problems in erosion–corrosion environments in a non-empirical fashion. Where do we go from here? Much experimental work still needs to be carried out to understand the mechanisms of erosion–corrosion of the wide range of materials and coatings available for combating erosion–corrosion damage. Based on such work, mechanistic models of the damage processes need to be continually developed and refined in order that a sound basis can be generated for the construction of such maps from theoretical methods. This paper summarizes the recent work carried out on the development of materials performance maps both in wet and dry erosion–corrosion conditions. The future challenges for the research community of the work in this area are described. An outline route map through which these important developments may be carried out is also described.

Some thoughts on the construction of erosion–corrosion maps for PVD coated steels in aqueous environments

In studies of erosion-corrosion of materials in aqueous conditions, there have been a few attempts to evaluate the performance of coatings. This is despite the fact that the use of coatings provides a relatively economic method of reducing erosion-corrosion damage in such environments. There has also, as a consequence, been no attempt to define a rationale for coating selection for exposure to various erosion-corrosion environments. The object of this work has been to address the above issues by investigating the effect of increasing velocity on a range of physical vapour deposition (PVD) coated and uncoated steels, at various applied potentials, in a carbonate/bicarbonate slurry solution containing alumina particles. The performance of two coatings, Ti2N and CrN was evaluated. The results were compared to those for the uncoated steel (mild steel) and 304 stainless steel, The results showed that the both the corrosion and passivation potentials for the coatings occurred at different values for the individual coatings. Hence, the erosion-corrosion regime maps differed for the different coating systems. Materials performance maps were constructed from the results, providing a basis by which the use of such coatings may be optimized for exposure to aqueous erosion-corrosion conditions. (C) 1999 Elsevier Science S.A. All rights reserved.

Synergism between effects of velocity, temperature, and alloy corrosion resistance in laboratory simulated fluidised bed environments

In studies of the erosion of alloys at elevated temperature, the combined effects of velocity, temperature, and alloy corrosion resistance are not well understood. Wide variations in the effects of velocity have been observed for alloys of different corrosion resistance in various erosion–corrosion environments. There is also some evidence that temperature can affect this relationship. The object of the present work was to undertake a systematic study of the effects of erodent velocity for two alloys, mild steel and 310 stainless steel, at elevated temperatures (300 and 600°C). The velocity was controlled at values between 1·5 and 4·5 m S−l. Weight change data and analytical scanning electron microscopy were used to characterise the degradation in the various conditions. The results showed that the ranking order of the erosion–corrosion rates of the two different alloys varied as a function of velocity. The velocity at which the ranking of the two alloys reversed increased with increasing temperature. The reasons for such behaviour are discussed in terms of the dependence of the erosion–corrosion rate on the velocity in the various erosion–corrosion regimes.MST/3188

95/05475 Relationship between the effects of velocity and alloy corrosion resistance in erosion-corrosion environments at elevated temperatures

95/05475 Relationship between the effects of velocity and alloy corrosion resistance in erosion-corrosion environments at elevated temperatures

Relationship between the effects of velocity and alloy corrosion resistance in erosion-corrosion environments at elevated temperatures

Erosion-corrosion by either solid particle or liquid impact occurs in a wide variety of industrial environments which range from coal conversion processes to steam turbines in nuclear power generation. The effects of erosion-corrosion depend on properties of the particle, the target and the nature of the corrosion environment. Various regimes of erosion-corrosion interaction have been identified, ranging from “erosion-dominated” (erosion of the substrate) to “corrosion-dominated” (erosion of the corrosion product). In studies of erosion-corrosion, the effects of impact velocity are generally not well understood. In some environments in which corrosion occurs, high velocity exponents have been reported, while, in others, the values are close to 1. In addition, the effects of alloy corrosion resistance in environments of different velocities have been puzzling with differences in the exponents reported, as alloy corrosion resistance is increased. This paper considers the effect of velocity for various erosion-corrosion studies from the literature. The effects of alloy corrosion resistance for such results are evaluated. Some general provisos for the interpretation of the effects of velocity will be made for alloys of different corrosion resistance in erosion-corrosion environments. It is shown that relative erosion-corrosion resistance of alloys in one environment cannot be used arbitrarily to predict resistance in other environments, particularly if parameters such as velocity are varied significantly.