Corrosion and tribocorrosion behaviors of AISI 316 stainless steel and Ti6Al4V alloys in artificial seawater

The corrosion and tribocorrosion behaviors of AISI 316 stainless steel and Ti6Al4V alloys sliding against Al2O3 in artificial seawater using a pin-on-disk test rig were investigated. And the synergistic effect between corrosion and wear was emphatically evaluated. The results show that the open circuit potentials of both alloys drop down to more negative value due to friction. The corrosion current densities obtained under tribocorrosion condition are much higher than those under corrosion-only condition. Friction obviously accelerates the corrosion of the alloys. The wear loss for both alloys is larger in seawater than that in pure water. Wear loss is obviously accelerated by corrosion. And AISI 316 stainless steel is less resistant to sliding damage than Ti6Al4V alloy. The synergistic effect between wear and corrosion is a significant factor for the materials loss in tribocorrosion. In this surface-on-surface contact geometry friction system, the material loss is large but the ratio of wear-accelerated-corrosion to the total wear loss is very low.

Tribocorrosion behaviors of Ti-6Al-4V and Monel K500 alloys sliding against 316 stainless steel in artificial seawater

The tribocorrosion behaviors of Ti-6Al-4V and Monel K500 alloys sliding against 316 stainless steel were investigated using a ring-on-block test rig in both artificial seawater and distilled water. It is found that friction coefficients are in general larger in distilled water compared with seawater. The wear losses of Ti-6Al-4V and Monel K500 alloys are larger in seawater compared with distilled water. The mechanical action can destroy the passive film and increase the corrosion rate. The synergism effect between corrosion and wear occurs. The synergism action between corrosion and wear is related to the corrosion rate and with the increase of corrosion rate, the synergism becomes more important. 316 stainless steel suffers severe wear sliding against Monel K500 alloy compared with sliding against Ti-6Al-4V alloy in both distilled water and seawater.

Crystalline texture evolution, control of the tribocorrosion behavior, and significant enhancement of the abrasion properties of a Ni-P nanocomposite coating enhanced by zirconia nanoparticles

This paper describes an investigation of the effect of ZrO2 nanoparticles on the abrasive properties,crystalline texture developments,and tribocorrosion behavior of Ni-P nanostructured coatings.In the investigation,Ni-P and Ni-P-ZrO2 nanostructured coatings are deposited on St52 steel via the electroless method.Transmission electron microscopy(TEM),field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD),energy dispersive spectroscopy(EDS),cyclic-static polarization tests in 3.5wt%NaCl solution,the tribocorrosion test(by back-and-forth wear in electrochemical cell),and the microhardness test using the Vickers method were performed to characterize and analyze the deposited coatings.The results of this study showed that the addition of ZrO2 nanoparticles to the Ni-P electroless bath produced the following:a sharp increase in wear and hardness resistance,the change of the wear mechanism from sheet to adhesive mode,the reduction of pitting corrosion resistance,significant reduction in the tribocorrosion protective properties,change in the preferred orientation of the crystalline texture coating from(111)to(200),increase in the sedimentation rate during the deposit process,and a sharp increase in the thickness of the Ni-P nanostructured coatings.

Microstructure and tribocorrosion performance of nanocrystalline TiN graded coating on biomedical titanium alloy

A nanocrystalline TiN graded coating was prepared on Ti6Al4V alloy by DC reactive magnetron sputtering method. The microstructure and mechanic properties of the coating were investigated. The electrochemical corrosion and tribocorrosion of the coated specimens in physiological environment were compared with those of Ti6Al4V substrate. The results show that the gradient distribution of nanocrystalline TiN is favorable for releasing the inner stress in the coating, which increases adhesion strength to 90 N. The compact structure and refined-grains of the coating result in the surface nanohardness of 28.5 GPa. The corrosion protection efficiency of the nanocrystalline TiN coating reaches 96.6%. The tribocorrosion resistance of the coating increases by 100 times in comparison with that of Ti6Al4V substrate. The high chemical stability and H3/E2 ratio (where H is hardness, and E is elastic modulus) of the nanocrystalline TiN coating are responsible for good corrosion and wear resistances.

Corrosion and tribocorrosion behavior of Ti6Al4V/xTiN composites for biomedical applications

The corrosion and tribocorrosion behavior of Ti6Al4V/xTiN(x=0,5,10 and 15,vol.%)composites fabricated by solid-state sintering and their relationship with the microstructure and microhardness were investigated.Simulated body conditions such as a temperature of 37℃ and a simulated body fluid were used.The main results demonstrated a microstructural change caused by theα-Ti stabilization due to solid-solution of nitrogen(N)into the titanium(Ti)lattice,producing a maximum hardening effect up to 109%for the Ti64 matrix by using 15 vol.%TiN.Corrosion potentials of composites changed to more noble values with the TiN particle addition,while corrosion current density of samples increased as an effect of the remaining porosity,decreasing the corrosion resistance of materials.However,changes to a less passive behavior were observed for samples with 15 vol.%TiN.The non-passive behavior of composites resulted in the reduction of the potential drops during rubbing in tribocorrosion tests.Besides,an improvement of up to 88%of the wear rate of composites was seen from the solid-solution hardening.The results allowed to understand the relationship between composition and sintering parameters with the improved tribocorrosion performance of materials.

Corrosion and tribocorrosion resistance of MAO-based composite coating on AZ31 magnesium alloy

In this paper, a multi-functional composite coating with low friction coefficient, high wear resistance and excellent tribocorrosion resistance is fabricated on AZ31 Mg alloys by micro-arc oxidation and spray-coating methods. The microstructure, and composition of the coating are characterized by SEM, EDS, XRD, and FT-IR. Potentiodynamic polarization and EIS tests are conducted to evaluate the corrosion resistance of the composite coating. The tribocorrosion property is also studied using pin-on-disk tribometer in 3.5 wt.% Na Cl solution. It is found that the composite coating possesses better long-term corrosion resistance than the single MAO coating. The tribocorrosion tests prove that the composite coating exhibits much better wear and tribocorrosion resistance than the single MAO coating and can protect the substrate from corrosion under a sliding condition.

Tribocorrosion behaviour of Ti6Al4V under various normal loads in phosphate buffered saline solution

Tribocorrosion tests were conducted on Ti6 Al4 V against alumina in phosphate buffered saline solution under normal loads of 3-30 N(corresponding to the maximum Hertzian contact pressures of 816-1758 MPa) using a ball-on-disk tribometer. Nano-hardness measurements revealed the formation of work-hardened layers on the pure wear and tribocorrosion surfaces. As the normal load increased from 15 to 30 N during the pure wear, the surface hardness was increased by about 100%. However, a lower generation of wear debris resulted in a lower wear rate under a normal load of 30 N. The presence of corrosion caused an increase in the wear rates by 28%-245% under various normal loads. The corrosion current density acquired from polarization curves was increased by three orders of magnitude and the open circuit potential(OCP) shifted to more negative potentials during tribocorrosion compared with the stagnant condition. The successive formation and removal of tribofilms, which consisted of oxygen and phosphorous compounds, resulted in peaks in the OCP trend and lower fluctuations in coefficient of friction under normal loads higher than 3 N.

Using fused filament fabrication to improve the tribocorrosion behaviour of 17-4 PH SS in comparison to other metal forming techniques

Fused filament fabrication(FFF)is one of the additive manufacturing processes which has gained more interest because of its simplicity and low-cost.This technology is similar to the conventional metal injection moulding(MIM)process,consisting of the feedstock preparation of metal powder and polymer binders,followed by layer-by-layer 3D printing(FFF)or injection(MIM)to create green parts and,finally,debinding and sintering.Moreover,both technologies provide near-dense parts.This work presents an in-depth study of the processing method’s influence.The porosity,microstructure,hardness,corrosion,and tribocorrosion behaviour are compared for 17-4 PH SS samples processed from powder by additive manufacturing using FFF and MIM,as well as conventional powder metallurgy(PM)samples.MIM samples exhibited the highest macro and microhardness,while corrosion behaviour was similar for both MIM and FFF samples,but superior in comparison to conventional PM samples.However,the FFF-as fabricated samples displayed a significant improvement in tribocorrosion resistance that could be explained by the higher proportion of delta ferrite and retained austenite in their microstructure.

Electrochemical Corrosion,Wear,and Tribocorrosion Behavior of Novel Ti-19Zr-10Nb-1Fe Alloy

The electrochemical corrosion,wear,and tribocorrosion behavior of the novel Ti-19Zr-10Nb-1Fe alloy were investigated.The electrochemical corrosion analysis results show that the corrosion resistance of the Ti-19Zr-10Nb-1Fe alloy is better than that of the Ti-6Al-4V alloy under the test conditions in this research.Compared with the static electrochemical corrosion,the corrosion resistance of Ti-19Zr-10Nb-1Fe alloy during tribocorrosion decreases significantly,because the wear accelerates corrosion.The wear volume of Ti-19Zr-10Nb-1Fe alloy is increased with the increase in applied load whether the electrochemical corrosion occurs or not.Due to the acceleration effect of electrochemical corrosion,the wear volume caused by electrochemical corrosion is larger than that without electrochemical corrosion.The results of Wa/Wc are much greater than 10,indicating that during the tribocorrosion process,the material loss caused by mechanical wear is much larger than that caused by electrochemical corrosion.Through SEM observation of the wear morphologies of Ti-19Zr-10Nb-1Fe alloy after tribocorrosion,it can be inferred that the micro-abrasion is the main wear mechanism.The above results show that during the tribocorrosion process,the corrosion accelerates wear,and the wear accelerates corrosion.

Impact–sliding fretting tribocorrosion behavior of 316L stainless steel in solution with different halide concentrations

Impact–sliding caused by random vibrations between tubes and supports can affect the operation of heat exchangers.In addition,a corrosive environment can cause damage,accelerating the synergism of corrosion and wear.Therefore,the focus of this work was the impact–sliding fretting tribocorrosion behavior of 316L heat exchanger tubes at different halide concentrations.A device system incorporating the in situ electrochemical measurements of impact–sliding fretting corrosion wear was constructed,and experiments on 316L heat exchanger tubes in sodium chloride(NaCl)solution with different concentrations(0.0,0.1,0.5,1.0,3.5,and 5.0 wt%)were carried out.The synergism between wear and corrosion was also calculated and analyzed.The wear and damage mechanisms were elucidated by correlating the corrosion–wear synergism,morphologies,and material loss rates.The results indicated that the stable wear stage occurred at approximately 9–12 h,after which the corrosion current increased with the expansion of the wear area.As the halide concentration increased,the scale of damage on the wear scars gradually decreased,changing from being dominated by cracks,delaminations,and grooves to being dominated by scratches,microgrooves,and holes.There was an obvious positive synergism between wear and corrosion.The material loss was dominated by pure mechanical wear and wear enhanced by corrosion,but corrosion enhanced by wear contributed more than tangential sliding fretting corrosion.The total mass loss increased gradually in the range of 0.0–0.5 wt%and decreased in the range of 0.5–5.0 wt%.Large-scale damage enhanced by corrosivity and small-scale damage reduced by lubricity dominated the material loss at low and high concentrations,respectively.

Tribocorrosion behavior in artificial seawater and anti-microbiologically influenced corrosion properties of TiSiN-Cu coating on F690 steel

The TiSiN-Cu nanocomposite coating was deposited on F690 steel substrate by arc ion plating. The structure and composition, tribocorrosion behavior and anti-microbiologically influenced corrosion(MIC)properties of TiSiN-Cu coating were investigated. The results show that the TiSiN-Cu coating has unique nanocomposite structures. The results of tribocorrosion show that the potential and current change of F690 steel and TiSiN-Cu coatings tend to be opposite. The reason is that the F690 steel is non-passivated metal and the TiSiN-Cu coating has passivation phenomenon. The TiSiN-Cu coating possesses excellent tribocorrosion resistance. Cu ion released from TiSiN-Cu coating can effectively inhibit the corrosion caused by SRB.

Tribocorrosion Behavior of 304 Stainless Steel in 0.5 mol/L Sulfuric Acid

The tribocorrosion behavior of 304 stainless steel was studied through comparing the damage behavior of 304 stainless steel in dilute sulfuric acid to that in distilled water by a reciprocating tribotester. The re-passivation behavior, the surface and sectional morphological features, as well as the change of microhardness of samples were studied, and the tribocorrosion mechanism was also discussed. The experimental results reveal that the damage of stainless steel in dilute sulfuric acid was caused by the steel＇s mechanical removal and electrochemical dissolution. The wear mechanism of stainless steel is abrasive wear, which mainly consists of micro-cutting and peeling. The synergetic action between corrosion and wear is notable. The corrosive environment leads to the embrittlement of the surface layer, and the wear destroys the passivation film and causes galvanic corrosion.

Tribocorrosion behavior of nickel-aluminium bronze sliding against alumina under the lubrication by seawater with different halide concentrations

The tribocorrosion failure mechanism of nickel-aluminium bronze(NAB) in different halide concentrations of seawater was studied using a pin-on-disc tribometer that was modified to conduct in-situ electrochemical detection during the sliding process. It has been reported that high-halide-concentration seawater provided a good lubricating effect, and thus reduced the coefficient of friction and wear rate of NAB during the tribocorrosion process. However, the existence of halide ions corroded the passive film and hindered the repassivation of the damaged areas in the wear track, resulting in an increased corrosion rate. In addition, the morphology of the wear scar revealed the occurrence of abrasive, delamination, and adhesive wear of NAB in seawater. For the whole range of halide concentration values, a positive synergy between wear and corrosion was proven, and the quantification of this synergy was discussed in detail. The results show that the corrosionwear synergism was decreased with increasing halide concentration in seawater, and the corrosion-induced wear was dominant in the two synergistic components.

Tailoring the microstructure,mechanical and tribocorrosion performance of (CrNbTiAlV)N_(x) high-entropy nitride films by controlling nitrogen flow

The(CrNbTiAlV)N_(x)high-entropy nitride films were fabricated by adjusting nitrogen flow via magnetron sputtering.The microstructure,mechanical,electrochemical and tribocorrosion performances of the films were studied.The results show that the films transform from amorphous to nanocrystalline structure as nitrogen flow increased.The nanocrystalline films show super hardness(>40 GPa)and adhesion strength(>50 N).The amorphous film has a pretty anti-corrosion in static corrosion,while not in tribocorrosion condition.The film deposited at nitrogen flow of 38 sccm exhibits the optimal tribocorrosion performance in artificial seawater,with the highest open circuit potential(∼−0.1 V vs.Ag/AgCl),the lowest friction coefficient(∼0.162)and wear rate(∼7.48×10^(−7)mm^(3)N^(−1)m^(−1)).

Long-term tribocorrosion resistance and failure tolerance of multilayer carbon-based coatings

Current tribocorrosion research of metallic materials and their surface protective coatings mainly focuses on their short-term properties,with test time of 0.5‒2.0 h and a sliding distance 50‒500 m,which may significantly deviate from the practical long-term service condition and thus cause a catastrophe of marine equipments.In this study,three carbon-based multilayer coatings(Ti/DLC,TiC_(x)/DLC,and Ti‒TiC_(x)/DLC)were deposited on S32750 substrates,and both short-term and long-term tribocorrosion behaviors were investigated.The experimental results indicate that the coatings substantially improve the tribocorrosion resistance of the S32750 stainless steel.During the short-term tribocorrosion test,TiC_(x)/DLC exhibited the best tribocorrosion resistance owing to its high hardness.During the long-term tribocorrosion test,however,Ti‒TiC_(x)/DLC coating indicated the best anti-tribocorrosion performance owing to its excellent fracture toughness together with high hardness.Moreover,under 5 N,Ti‒TiC_(x)/DLC can withstand a long-term test of more than 24 h.Additionally,under a higher load of 20 N,the Ti‒TiC_(x)/DLC with a corresponding sliding distance of approximately 1,728 m maintained a low friction coefficient of approximately 0.06.However,the coating was completely worn out;this is attributable to the formation of tribocorrosion products consisting of graphitized carbon and nanocrystalline Fe_(x)O_(y).

Accelerated deterioration mechanism of 316L stainless steel in NaCl solution under the intermittent tribocorrosion process

In this research,the tribocorrosion behavior of 316L stainless steel in simulated seawater was investigated under continuous and intermittent sliding at open circuit potential.The tribocorrosion mechanism was discussed in terms of wear morphologies,mechanical property as well as chemical composition.Meanwhile,microstructure evolution inside the wear track and open circuit potential recorded after sliding were analyzed to quantify the repassivation kinetics and evaluate the impact of the regenerated passive film on wear.The results showed that the wear rate increased under intermittent sliding when the pause time is long enough to repassivate after sliding.Repeated sliding promoted the refinement of the grain inside the sliding area,which was beneficial to the generation of the thicker and more compact passive film inside the wear track.The ruptured passive film often acted as abrasives during subsequent sliding.Therefore,the accelerated material loss under intermittent sliding was attributed to the periodic mechanical removal of the thickened passive film and the enhanced abrasive wear inside the wear track.

Tribocorrosion behavior of antibacterial Ti-Cu sintered alloys in simulated biological environments

Ti-Cu alloys have strong antibacterial proper-ties,high strength and excellent corrosion resistance,which might be used in orthopedic and dental implants.In this paper,the tribocorrosion behaviors of Ti-Cu alloy with different Cu contents were investigated in four simulated biological environments compared with cp-Ti.The results showed that Ti-Cu sintered alloy exhibited higher corro-sion resistance,lower coefficient friction and wear loss than cp-Ti in all tested solutions due to the formation of fine and homogeneously distributed Ti_(2)Cu phase,espe-cially in solution with lower F ion and pH.High Cu content and extrusion process improved the corrosion resistance and the wear resistance because of high Ti_(2)Cu phase fraction and fine grain size.However,aggressive solution,such as the solution with lower F ion and pH,accelerated wear in comparison with other solutions for cp-Ti and Ti-Cu sintered alloys.Scanning electron microscope(SEM)surface morphology demonstrated that the wear mecha-nism of cp-Ti during tribocorrosion process was mainly abrasive wear and adhesive wear while that of Ti-Cu alloy was abrasive wear.In summary,Ti-Cu sintered alloys showed much better tribocorrosion property than cp-Ti,which shows great potential application in condition for wear and corrosion resistance.

Structure and tribocorrosion behavior of CrMoSiCN nanocomposite coating with low C content in artificial seawater

CrMoSiCN nanocomposite coatings with a low C content were prepared on Ti−6Al−4V using an unbalanced magnetron sputtering system,and their corresponding microstructures,mechanical properties,and tribocorrosion performance were evaluated in detail.The results revealed that the CrMoSiCN coating had a compact nanocomposite microstructure consisting of CrN and Mo2N nanocrystallites,(Cr,Mo)N solid solution,and Si−C−N amorphous phases.Moreover,the coating exhibited superior mechanical properties with a hardness of 28.6 GPa and an elastic modulus of 273 GPa,owing to the solid solution strengthening effect.The tribocorrosion test results showed that the dominant failure of the Ti−6Al−4V alloy was caused by the corrosion contribution to wear behaviors(synergistic effect).The CrMoSiCN nanocomposite coating could effectively alleviate the material loss caused by the synergistic effect of corrosion and wear behaviors,leading to pure wear behaviors during the entire tribocorrosion process.The corresponding tribocorrosion mechanisms under the open circuit potential and dynamic polarization conditions were discussed in terms of their tribocorrosion behaviors.

Tribocorrosion Behavior and Degradation Mechanism of 316L Stainless Steel in Typical Corrosive Media

The tribocorrosion behavior and degradation mechanism of 316 L stainless steel,in four typically industrial corrosion media,under different potentials,were studied.The results indicated that they strongly depended on corrosion medium and electrode potential.When the potential increased from cathodic protection region to anodic region,corrosion was accelerated.It dramatically promoted mechanical wear which even dominated the total material loss.As a result,the total material loss increased sharply,though the material degradation directly caused by corrosion was slight.This phenomenon was more noticeable when the media were more aggressive.Especially in NaCl solution,the occurrence of pitting corrosion at anodic potential dramatically accelerated the degradation of the stainless steel.There was a special case in NaOH solution under cathodic protection potential.The corrosive reaction could still occur and couple with wear,which led to the abnormally great material loss compared with that in other corrosion media.

An integrated hard- and soft-ware triboelectrochemical test rig for tribocorrosion experiments

Tribocorrosion is a degradation mechanism resulting from the interaction of mechanical(wear)and chemical(corrosion)phenomena.This interaction leads to surface damage that does not correspond to the simple sum of wear and corrosion taken separately.Testing tribocorrosion of material pairings thus requires the capability not only to control the mechanical and chemical test parameters but also to identify the relative contribution of corrosion and wear in the overall material degradation.This paper describes a novel laboratory tribocorrosion test set-up combining in one experiment the control of mechanical input(load,velocity,and frequency)and output(friction and wear)parameters as well as the control of corrosion phenomena through a series of dedicated electrochemical methods(open circuit,potentiostatic and potentiodynamic measurements).The possibilities offered by this set-up are illustrated by selected case studies.