Passive Transition Research Articles

MILP model for short-term peak shaving of multi-grids using cascade hydropower considering discrete HVDC constraints

The thriving of high-voltage direct current transmission for hydropower tackles supply-demand imbalances but complicates grids safety, especially concerning the related challenges of varying numbers of hydroelectric units operating, including the effects of discrete rectifier station altering current and vibration zones with minimum numbers of hydroelectric units operating. Here, a mixed integer linear programming model considering high-voltage direct current safety constraints for daily peak-shaving of cascade hydropower plants serving multi-grids is proposed to address these challenges. First, the model integrates the altering current constraint across multiple intervals to ensure stable operation following the passive transition of the direct current terminal into islanded system state. Second, a power distribution strategy considering load differences is adopted to compensate for shortcomings of traditional peak shaving treatments for multiple grids to achieve effective results. Finally, a method for linearizing the segmented vibration zones of hydropower station with minimum numbers of units operating is adopted during model solving to ensure that the model meets safe specifications. The case study indicates that besides guaranteeing the proposed security constraints, the model reduces the average distance by 30.4 % and 30.3 % during the dry and flood seasons, respectively, with better calculation time and variance of the residual load.

Correlative evaluation of the corrosion resilience and passivation properties of zinc and aluminum alloys in neutral chloride and acid-chloride solutions

Abstract Comparative analysis of the corrosion resilience and passivation characteristics of pure zinc (Zn) and aluminum (Al) alloys in neutral chloride and acid-chloride solutions at 0.5–3% NaCl concentrations was done with potentiodynamic polarization, potentiostatic evaluation, optical characterization, and open circuit potential measurement. Results show Al alloy was more resistant to general corrosion in both solutions with values ranging from 0.031 to 0.082 mm/year, and 0.037 to 0.389 mm/year compared to Zn alloys with values of 0.432–0.691 mm/year and 0.465–5.016 mm/year. Corrosion potential values of Zn alloy were significantly more electronegative than the values for Al alloy. The passivated region of the polarization plots for Al was thermodynamically unstable with visible current transients compared to that of Zn. Passivation of Al occurred at the early onset of anodic polarization in the neutral chloride solution. Zn alloy passivated at specific potentials, coupled with stable passivation behavior. The passivation range values of Al were generally greater than the values for Zn due to delayed stable pitting activity. Optical images for Al showed extensive localized degradation along specific regions and grain boundaries, whereas Zn morphology indicates general surface degradation. Open circuit potential plots indicate significant growth of Al2O3 oxide on Al coupled with active–passive transition behavior of the oxide. This contrasts the observation for Zn where the plot configuration indicates limited oxide formation and growth but significant thermodynamic stability.

Patterning and dynamics of membrane adhesion under hydraulic stress

Hydraulic fracturing plays a major role in cavity formation during embryonic development, when pressurized fluid opens microlumens at cell-cell contacts, which evolve to form a single large lumen. However, the fundamental physical mechanisms behind these processes remain masked by the complexity and specificity of biological systems. Here, we show that adhered lipid vesicles subjected to osmotic stress form hydraulic microlumens similar to those in cells. Combining vesicle experiments with theoretical modelling and numerical simulations, we provide a physical framework for the hydraulic reconfiguration of cell-cell adhesions. We map the conditions for microlumen formation from a pristine adhesion, the emerging dynamical patterns and their subsequent maturation. We demonstrate control of the fracturing process depending on the applied pressure gradients and the type and density of membrane bonds. Our experiments further reveal an unexpected, passive transition of microlumens to closed buds that suggests a physical route to adhesion remodeling by endocytosis.

Effects of minor alloying elements (Si, Mn and Al) on the corrosion behavior of stainless steels in molten carbonate fuel cell cathode environment

Abstract Effects of minor alloying elements (Si, Mn, and Al) on the corrosion resistance behaviors of stainless steel (SS) modified 310S used as a cathode current collector (CCC) material for molten carbonate fuel cells (MCFC) were examined in a mixture of 62 mol% Li2CO3–38 mol% K2CO3 at 650 °C by measuring the change in corrosion potential and the potentio-dynamic, potentio-static polarization responses. The corrosion potential of modified 310S gradually increased after 9 h of immersion due to an active to passive transition and that of SSs added with minor alloying elements drastically increased before 6 h of immersion due to the reactive alloys. Si, Mn, and Al addition to base SS led to a decrease in corrosion resistance due to the rapid corrosion rate at the cathode operation potential, −40 mV, of the MCFC. The steady state current densities of SSs added with minor alloying elements were higher than that of 310S and modified 310S. Addition of Si, Mn, and Al induced a decrease in corrosion resistance of CCC materials in molten carbonate fuel cell operating temperatures, 650 °C.

Post-Activation Performance Enhancement (PAPE) interventions at different loads may enhance sprint performance in well-trained athletes

Objective: The aim of this study was to evaluate and compare the effects of back squat exercise on subsequent sprint performance in resistance-based Post Activation Performance Enhancement (PAPE) intervention with two different loads and repetitions. Material and Methods: Subjects performed three experimental runs in the laboratory for at least 48 hours apart. At the first experimental visit, anthropometric evaluations, sprint performance and one-repetition maximum (1RM) tests were performed. On the next two visits, each subject completed a standardized warm-up on the bicycle ergometer at 30 watt/ 60 cadence for 5 minutes, and after a passive transition phase period of 5 minutes, they performed the resistance based back squat PAPE protocol. After a 12-minute passive transition phase period, subjects performed the sprint cycling performance. Results: PAPE interventions with 1RM%60x6 reps (moderate rep-moderate load) and 1RM %90x3 reps (low rep-high load) loads resulted in statistically insignificant slight improvement in mean power values (p<0.47), and no significant effect on peak power (p<0.91), and fatigue index (p<0.79) in sprint cycling performance. Conclusion: The PAPE interventions resulted in a slight increase in the mean power values when compared to the control condition. However, there was no statistically significant difference between the two differential loads.

Protein secretion zones during overexpression of amylase within the Gram-positive cell wall

BackgroundWhereas the translocation of proteins across the cell membrane has been thoroughly investigated, it is still unclear how proteins cross the cell wall in Gram-positive bacteria, which are widely used for industrial applications. We have studied the secretion of α-amylase AmyE within two different Bacillus strains, B. subtilis and B. licheniformis.ResultsWe show that a C-terminal fusion of AmyE with the fluorescent reporter mCherry is secreted via discrete patches showing very low dynamics. These are visible at many places within the cell wall for many minutes. Expression from a high copy number plasmid was required to be able to see these structures we term “secretion zones”. Zones corresponded to visualized AmyE activity on the surface of cells, showing that they release active enzymes. They overlapped with SecA signals but did not frequently co-localize with the secretion ATPase. Single particle tracking showed higher dynamics of SecA and of SecDF, involved in AmyE secretion, at the cell membrane than AmyE. These experiments suggest that SecA initially translocates AmyE molecules through the cell membrane, and then diffuses to a different translocon. Single molecule tracking of SecA suggests the existence of three distinct diffusive states of SecA, which change during AmyE overexpression, but increased AmyE secretion does not appear to overwhelm the system.ConclusionsBecause secretion zones were only found during the transition to and within the stationary phase, diffusion rather than passive transport based on cell wall growth from inside to outside may release AmyE and, thus, probably secreted proteins in general. Our findings suggest active transport through the cell membrane and slow, passive transition through the cell wall, at least for overexpressed proteins, in bacteria of the genus Bacillus.

Discerning the process of cultivated land governance transition in China since the reform and opening-up-- Based on the multiple streams framework

Cultivated land is a key resource for human survival and development. Understanding what has promoted the cultivated land governance transition (CLGT) is enlightening to improve cultivated land governance (CLG), then cope with the problems closely related to cultivated land that challenge the sustainable development of human societies, of critical importance. Based on the concept of transition, this paper constructs a theoretical model of the CLGT in China, designs an evaluation index system of CLG, and uses the elbow-kmeans method to identify the cycle and turning points of the CLGT in China from the reform and opening-up to 2020. Then, it introduces the multiple streams framework to summarize the paths of the CLGT. The results indicate that the curve of the CLGT in China shows a "W-shape", including two transition cycles in 1984–1999 and 1999–2020 and two turning points in 1989 and 2003. The first CLGT in China is a demand-induced passive transition, and the second CLGT is a supply-led initiative transition. There are three paths promoting the CLGT, namely, the institutional path, the emergency path and the reconstruction path. The positive benefits of the first two paths counteract the negative impact of the problem stream and halt the decline in CLG output, and the third path promotes the CLG output increase. Finally, China's CLG has not yet achieved SDG 12. This paper recommends the establishment of a CLG early warning platform and the launch of a Cultivated Land Environmental Quality Incentive Program to promote an increase in the output of CLG in China, and ultimately achieve the Sustainable Development Goals.

Multi-input multi-output phononic subsurfaces for passive boundary layer transition delay

This paper documents progress towards developing a passive boundary layer transition delay strategy using a phononic subsurface (PSub). High-order implicit large-eddy simulation (ILES) is used to explore control requirements for boundary layer transition delay in the context of guiding passive flow control strategies. Positive phasing of surface displacement relative to forcing from a Tollmien-Schlichting (T-S) wave is shown to be effective at attenuating instability for the present flow conditions. Although difficult to achieve with a single input system, positive phasing can be realized with a multi-input, multi-output (MIMO) system. To this end, a MIMO PSub was developed and a reduced-order model was coupled with the flow solver. Positive phasing, and therefore a small degree of passive transition delay, was demonstrated on a flat plate boundary layer. Further optimization of subsurface properties and placement of multiple devices are likely to improve controller efficacy.

Investigating the activation of passive metals by a combined in-situ AFM and Raman spectroscopy system: a focus on titanium

Understanding the main steps involved in the activation of passive metals is an extremely important subject in the mechanical and energy industry and generally in surface science. The titanium-H2SO4 system is particularly useful for this purpose, as the metal can either passivate or corrode depending on potential. Although several studies tried to hypothesise the surface state of the electrode, there is no general consensus about the surface state of Ti in the active–passive transition region. Here by combining in-situ atomic force microscopy (AFM) and Raman spectroscopy, operating in an electrochemical cell, we show that the cathodic electrification of Ti electrodes causes the dissolution of the upper TiO2 portion of the passive film leaving the electrode covered by only a thin layer of titanium monoxide. Fast anodic reactions involved the acidification of the solution and accumulation of sulphur containing anions. This produces a local increase of the solution turbidity, allowing to distinguish favourable regions for the precipitation of TiOSO4·2H2O. These results give a clear answer to the long-stated question of the physical origin behind the formation of negative polarization resistances, sometimes occurring in corroding systems, and a rationale about the proton-induced degradation of passive surfaces in presence of sulphur containing species.

Electrochemical micro-couple mechanism based on Si and Mn segregations revealing the initiation of grain boundary dissolution for Q235 carbon steel

The purpose of this work was to reveal the initiation mechanism of grain boundary dissolution (GBD) for carbon steels in acidic electrolytes containing NO2–. For Q235 carbon steel in a HNO3-NaNO2 solution with pH 4, the electrochemical methods of potentiodynamic polarization and scanning Kelvin probe force microscope (SKPFM) were applied to explore electrochemical behavior, and the surface methods of scanning electron microscope (SEM), electron back-scatter diffraction (EBSD) and scanning tunneling microscope (STM) were applied to explore surface microstructure and composition. Q235 carbon steel presented the electrochemical behavior of activation-passivation-transpassivation in pH 4 HNO3-NaNO2 solution, GBD occurred on steel surface during anodic polarization. GBD initiation, which showed a selective characteristic, was found at the grain boundaries of relatively high Si and Mn contents (high Si-Mn grain boundary) when Q235 carbon steel was polarized to active–passive transition potential. The grain boundary segregations of Si and Mn played a critical role in the initiation of GBD, and an electrochemical micro-couple (EMC) mechanism based on the Si and Mn segregations was proposed to reveal GBD initiation. EMC potential difference between high Si-Mn grain boundary and grain interior was greater than that between low Si-Mn grain boundary and grain interior, resulting in that GBD initiated at high Si-Mn grain boundary. The detailed EMC mechanism of GBD initiation was discussed in this work.

The passivity breakdown of zinc antimony alloy as an anode in the alkaline batteries

Zn is utilized as an anode in alkaline batteries because of its propensity to produce a passive colloidal layer on its surface. Then the surface should be reactivated in the passive region. Therefore, the passive state on the surface can be significantly hindered by utilizing a tiny percentage of Sb alloyed with Zn. Accordingly, the effect of minor Sb alloying with Zn on the performance of anodic dissolution and passivation in concentrated alkaline media (6 M KOH, which is used in the batteries) was studied using potentiodynamic and potentiostatic techniques. Besides, the passive layers formed at various anodic potentials were characterized utilizing scanning electron microscopy (SEM) and X-ray diffraction (XRD). The data of potentiodynamic measurements exhibited the active–passive transition curve of all studied specimens. All obtained results revealed that passivation is gradually hindered with increasing Sb content in the alloy, and less passivity was obtained at 1% Sb. Along this, a dramatic rise in current density at a particular positive potential (+ 2.0 V vs. SCE) to markedly higher values only of the electrodes containing Sb is observed.

Awaruite (Ni3Fe), a new large nickel resource: Electrochemical characterization and surface composition under flotation-related conditions

Awaruite is a native nickel–iron alloy (Ni3Fe), found in serpentinized ultramafic rocks, that has gained interest as a possible source of nickel. FPX Nickel is advancing a very large awaruite deposit in central British Columbia, Canada, on which this work is based. To date there is limited information available regarding the flotation conditions to selectively concentrate awaruite from gangue minerals in serpentinite ores. The aim of this work was to investigate the floatability of awaruite in different solution conditions with a xanthate collector. Awaruite readily floated in acidic solution with a xanthate collector but not in neutral and alkaline solutions. Voltammograms on awaruite indicated that the alloy shows an active passive transition behaviour in acidic solution and passive behaviour in neutral and alkaline solutions. The passivation layer formed in neutral and alkaline solutions showed to inhibit the interaction between xanthate and awaruite surface. Infrared spectra on awaruite showed the presence of xanthate compounds attached to the surface in acidic condition at potentials higher than the reversible potential of xanthate/dixanthogen. Based on experimental results, it was postulated that xanthate chemisorbs on awaruite and then it oxidizes to form dixanthogen. Also, it was demonstrated that when passivated, awaruite quickly activates in acidic solution, good flotation performance was achieved with 10 min of conditioning, and similar performance was obtained after 30 min of conditioning. This work serves as a confirmation that is possible to float awaruite using xanthate, a well-known collector that offers selectivity over oxides and silicate minerals, which are the main gangue minerals in serpentinite ores.

Corrosion behavior of cold-rolled metastable Cr–Mn–Ni–N austenitic stainless steel in acidic NaCl solution

The microstructure and corrosion behavior of metastable austenitic stainless steel (MASS) 14Cr10Mn in acidic 1 wt.% NaCl solution were investigated by X-ray diffraction (XRD), electron back scatter diffraction (EBSD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurement techniques. Cold rolling deformation noticeably increases the contents of martensites and microdefects in the steel. All specimens show active–passive transition during the anodic polarization process. With changing the cold rolling reduction from 0% to 20%, the active corrosion rate markedly increases about 55%, whereas the pitting potential slightly decreases about 80 mV. The cold rolling deformation clearly facilitates the preferential dissolution of Fe and Cr as well as the enrichment of Cu on the metal surface in the corrosion process. The small shallow grooves and pits form at the deformation band regions.

Effects of Heat Treatment on Microstructures and Properties of Cold Rolled Ti-0.3Ni Sheets as Bipolar Plates for PEMFC

As promising materials for bipolar plates substrate, as-cold rolled Ti-0.3Ni (wt.%) sheets were heat treated with three different processes in this work. As-cold rolled sheets consist of α matrix and dispersed Ti2Ni intermetallic precipitates, and typical Widmanstatten microstructure can be observed after heat treatment. Lamellar Ti2Ni precipitates inside the colonies. Elongation of as-cold rolled sheets equals less than 7% while this value rises up to around 20%, and tensile strength decreases by more than 47% after heat treatment. Open circuit potentials of as-cold rolled sheets treated at 950 °C for 1 h followed by wind cooling (950 °C/1 h/WC), sheets aged at 500 °C for 3 h followed by air cooling (950 °C/1 h/WC + 500 °C/3 h/AC), and sheets treated at 950 °C for 1 h followed by furnace cooling (950 °C/1 h/FC) equals −0.536 V, −0.476 V, −0.486 V, −0.518 V, respectively. A potentiodynamic polarization test reveals that all of the specimens exhibit typical active–passive transition behavior. Sheets treated at 950 °C/1 h/WC possess the lowest corrosion current density (155.4 μA·cm−2). Results of electrochemical impedance spectroscopy (EIS) show that 950 °C/1 h/WC treated sheets possess the largest polarization resistance (Rpol), 122.6 Ω·cm2. Moreover, steady-state current densities (Iss) increase in the order of 950 °C/1 h/WC, 950 °C/1 h/WC + 500 °C/3 h/AC, 950 °C/1 h/FC according to the results of potentiostatic polarization. This can be attributed to various amounts of Ti2Ni precipitation caused by different cooling rates.

Tuning microstructure and improving the corrosion resistance of Ti-6Al-3Nb-2Zr-1Mo alloy using the electron beam freeform fabrication

Herein, the microstructure and corrosion behavior of Ti-6Al-3Nb-2Zr-1Mo alloy manufactured by the electron beam freeform fabrication (EBF3) have been thoroughly investigated. The evident prior-β grain boundary, the inside of which is composed of predominant α-lath and slight β-phase, is achieved. The EBF3-manufactured alloy displays a significantly improved corrosion resistance compared to the wrought alloy, especially the XY-plane. The X-ray photoelectron spectroscopy results reveal the formation of a more stable oxide film for the EBF3-manufactured alloy due to a higher fraction of phase boundaries induced by the fine α-laths; besides, the heterogeneous distribution of compositions between α- and β-phases can be effectively alleviated, resulting in the absence of the strong galvanic corrosion, which has been illustrated combined experiments and ab-initio calculations. The electrochemical analyses indicate that all samples exposed to the artificial seawater exhibit a typical spontaneous passive behavior, deriving from the presence of a compact oxide film, while a active–passive transition behavior is observed in 5 M HCl, stemming from the formation of a non-protective porous oxide film, which is well interpreted using the mixed potential theory. In addition, the oxygen reduction reaction, determined by diffusion and charge-transfer processes, is the predominant cathodic reaction in the artificial seawater, whereas, in 5 M HCl, the cathodic reaction is primarily associated with the hydrogen evolution reaction controlled by the discharge step.

CORROSION INHIBITION PERFORMANCE OF COMMIPHORAMYRRHA AND CYMBOPOGON OIL EXTRACT ON A36 CARBON STEEL CORROSION IN SULPHATE AND CHLORIDE ELECTROLYTE

Corrosion resistance of A36 carbon steel was assessed in 0.5[Formula: see text]M H2SO4 and HCl media in the presence of specific concentrations of Commiphoramyrrha (CM), Cymbopogon (CP) essential oil extracts and their combined admixture (CMCP). Values from potentiodynamic polarization showed CM extract reacted poorly in both acids at low concentration, but effectively at higher concentrations with optimal performance of 89.76% and 92.83%. CP extract generally performed effectively with inhibition values above 90%. CMCP performed very poorly in H2SO4 compared to its performance in HCl which was generally above 80% inhibition efficiency. The oil extracts exhibited mixed-type inhibition effect coupled with dominant anodic shift in corrosion potential and similar anodic slope configuration at all extract concentrations. ATR-FTIR spectra plots showed that most of the identified functional groups within the extract molecules generally adsorbed unto the A36 steel surface. Curves from open circuit potential analysis showed CM extract in H2SO4, and CP extract in H2SO4 and HCl solution significantly decreased the thermodynamic tendency of A36 steel to degrade. The curves of other extracts displayed significant time and extract concentration dependent active–passive transition behavior. Optical images of the unprotected steel exhibited severe general and localized surface deterioration compared to the inhibited steel with significantly protected morphology. Weight-loss analysis showed the effective protection effect of CP extract in both acids and CMCP in H2SO4 is independent of time and concentration from the onset of exposure compared to their remaining counterparts whose performance significantly varies over time and is concentration dependent. X-ray phase identification diagrams and identified patterns list revealed the presence of FeO(OH) on the steel surface without oil extracts while the phase compounds identified in the presence of the extracts are FeNi and Fe3C.

Evaluation of the influence of alumina nano-particle size and weight composition on the corrosion resistance of monolithic AA1070 aluminium

Corrosion resistance of AA1070 aluminium alloy (AA1070) was compared to AA1070 reinforced with alumina at weight composition (wt. %) of 5% and 10%, and grain size of 150 nm and 600 nm. Potentiodynamic polarization and open circuit potential analysis were employed in 0.0125 M H2SO4, 3.5% NaCl and 0.0125 M H2SO4-3.5% NaCl solutions. Data showed 0.0125 M H2SO4-3.5% NaCl solution was the most deleterious with peak corrosion rate value of 6.682 mm/y while 3.5% NaCl solution was the weakest with peak value of 0.084 mm/y. AA1070 at 5% (wt. %) and 150 nm particle size generally displayed the highest corrosion rate with values between 0.084 and 6.682 mm/y. However, visible decrease in corrosion rate occurred with increase in alumina weight fraction and particle size due to growth of the protective oxide on the composite and reduction of discontinuities to minimal values between 0.031 and 2.192 mm/y at 10% alumina weight fraction and 600 nm particle size. Cathodic and anodic reaction mechanisms significantly differs with respect to the electrolyte. Anodic reaction mechanism appeared under activation control in the sulphate-chloride and chloride solution, compared to cathodic reaction mechanism in the sulphate and sulphate-chloride solutions. Significant anodic degradation reaction was prevalent on the anodic polarization plot in the sulphate solution. Plots from open circuit potential analysis shows the composites and monolithic Al were the most thermodynamically stable in H2SO4 solution. In the sulphate-chloride solution, significant potential transients coupled with high corrosion tendency are conspicuous. The plot showed chaotic thermodynamic behaviour active passive transition behaviour of the passive film.

Microstructural and selective dissolution analysis of 316L austenitic stainless steel

Austenitic stainless steels (ASS) are among the most used structural materials because of their excellent mechanical and corrosive properties. In addition, 316L ASS has excellent weldability because of its low carbon content. This steel normally contains 5–10% residual delta ferrite to avoid hot cracking and micro-fissuring of the weld metal. Many studies show that selective dissolution of austenite or ferrite can occur in 316L steel. In a survey of the selective dissolution of phases in duplex stainless steel (DSS), Lo and coauthors studied the effect of electrolyte composition (H2SO4 + HCl solutions) on the active–passive transition. They showed that corrosion occurred only in the austenitic phase in solutions of 2M H2SO4 + 0.25–1.2M of HCl. Increasing the % of HCl, > 1.2%, austenite, and ferrite contributed to the corrosion process. The present authors did not find the effect of this electrolyte in the study of selective corrosion in 316L ASS welded in the literature. Therefore, this study aims to determine how the phases behave on 316L ASS by applying 2M H2SO4 + 1.5M HCl solution. In this work, we welded the steel by the autogenous TIG process using three heat inputs. The purpose of welding was to obtain different amounts and morphology of ferrite and determine whether this affected the selective dissolution of the phases. After the corrosion tests, the samples showed selective austenite corrosion irrespective of the volume fraction and morphology of the ferrite. In summary, the corrosive etches severely consumed the austenite because of the significant difference in the electrochemical potential between the phases. Therefore, with more nickel, austenite functioned as an anodic region, and the δ-ferrite, with more chromium, worked as a cathodic region.

A Study on The Electrochemical Behaviour of 416 and 440C Martensitic Stainless Steels in Alcohols.(Dept.M)

The electrochemical behaviour of AISI 416 and 440 martensitic stainless steel in alcoholic solutions (ethanol, iso-propanol and t-butanol) containing different concentractions of sulfuric acid (0,1 to 2M) has been investigated using potentiostatic anodic-cathodic polarization techniques. An activ- passive transition behaviour were observed and the critical current density (CD) for passivity was found to be dependent on tile concentration of acid in alcohols. The effect of water additions (5, 10, 15%) to IM H2So4 alcohols has been also investigated. It was found that the presence of water strongly influences the passivation of both steels in IM H2SO4 - alcoholic solutions.

Tribocorrosion Behaviour of Biomedical Porous Ti–20Nb–5Ag Alloy in Simulated Body Fluid

Porous Ti–20Nb–5Ag (wt.%) alloy was developed using powder metallurgy (PM) route with the porosity of 43% after sintering in a high vacuum atmosphere. The microstructure of the porous alloy revealed various micro, macro and interconnected pores with an average pore size of about 114 µm. Tribocorrosion behaviour of the porous alloy was examined in simulated body fluid under the various applied load of 1–10 N using DC electrochemical corrosion technique and kinetic parameters (corrosion potential, corrosion current density and breakdown potentials). After tribocorrosion test, the OCP values decreased from 0.17 to − 0.49 VSCE as applied load was increased. The potentiodynamic polarization results revealed that the corrosion potential decreased, while corrosion current density increased under higher applied loads. Active–passive transition plots showed metastable passivity due to severe fluctuations of passive current density. After tribocorrosion, the surface morphology was analysed using SEM, and it exhibited the severity of wear tracks at higher applied loads. The results indicated that the developed porous Ti–20Nb–5Ag alloys exhibit better tribocorrosion properties in simulated body fluid. Through observations of SEM images of the worn surfaces, the visible scratches and deep grooves were observed along the sliding direction, indicating a predominant abrasive mechanism.