Corrosion Attack Research Articles

Assessment of corrosive attack of Fe9Cr1Mo alloys in pressurised CO2 for prediction of breakaway oxidation

To provide clarity on the poorly-understood mechanism of breakaway oxidation, corrosion of Fe9Cr1Mo steel in pressurised CO2 is quantified and modelled. The temperature range 400–640∘C, relevant to nuclear power plants, is emphasised. Attack is in the form of combined oxide scale growth and internal carburisation of the metal. Carbon activity in the metal at its surface exhibits a strong time dependence consistent with the kinetically-limited transport of carbon due to the slow Boudouard reaction. Breakaway is associated with the approach to saturation of the steel with respect to carbon. Diffusion modelling agrees well with steel carbide precipitation observations.

Recent developments in utilization of nano silica in self‐compacting concrete: A review

AbstractSelf‐compacting concrete (SCC) is a type of flowable, high‐strength and high‐performance concrete in the construction field, which can flow and compact under its own weight. The damage of concrete is often caused by internal microstructural defects. Nano silica (NS) has excellent pozzolanic properties, and with an appropriate content of NS as auxiliary cementing material, it can promote the generation of C‐S‐H gels in addition to serve as internal filler, thus improves the micro‐scale defects in concrete. This paper extracts data from studies published over the last decade which focus on the application of NS in SCC and discusses the similarities and differences between the studies. Ultimately, a systematic review of the physical and chemical characteristics of NS, and the effect of NS on the workability, mechanical and durability properties of SCC is presented. Based on the review, the most common NS content is 0%–6%, where the negative effect of 0%–6% NS on the workability of SCC can be controlled by increasing the dosage of superplasticizer. The NS content of 2%–3% is optimum for improving the mechanical strength and the ability of SCC to resist water permeability, corrosion, acid and sulfate attacks, elevated temperature as well as shrinkage.

A Review on The Inhibition Efficiency of Green Materials as a Potential Corrosion Protection on Ferrous and Non-Ferrous Metals in Various Environments

Greenmaterial is a beneficial material in combating corrosion on any metallic structure. Since it is a green material, hence it can be classified as an environmental friendly material. Environmental friendly material (eco-friendly) is the best material choice to be opted for corrosion mitigation. Eco-friendly materials produce no pollution to the environment, safe to be used because of organic materials, made from a waste product or a natural resource, cheap, wide range of availability, renewable resource, freeof heavy metals and free of toxic compounds. Therefore, numerous research studies have been done worldwide by researchers as to study the effectiveness in term of inhibition efficiency of the eco-friendly material as corrosion mitigation method. This review highlighted a few eco-friendly materials such as rice husk, egg shell, banana peel and henna that have been tested successfully in the previous research studies as corrosion prevention method. Many of related and relevant research articles to this review topic have been included as to review the inhibition efficiency of the eco-friendly materials in corrosion mitigation. The result showed that the inhibition efficiency for all green materials reviewed was mainly above 90%. This showed that the green materials acted as a remarkable material either as a direct corrosion inhibitor or incorporated into a coating. The corrosion rate on metal was decreased as the molecules of green material being absorbed on the metal surface, creating a protective barrier and protected the metal surface from corrosion attack. This review provided the significant and valuable information regarding the application of eco-friendly material as corrosion mitigation because the facts in this review have indicated that the eco-friendly materials have an excellent inhibition efficiency for corrosion protection purpose on different metals in various environments.

Influence of roughness on the early corrosion of API steels by atomic force microscopy (AFM): A real-time assessment

Roughness surface significantly affects the corrosion process of steels. However, this relationship in early stages at the local level has not been well studied. The mechanisms associated with the beginning of corrosion are thus not well known. Likewise, the lateral distribution of roughness is rarely considered, which can lead to inaccurate representations of surface features. Herein, the effect of roughness on the deterioration of carbon steels was locally studied by means of a fluid cell (FC) coupled to an atomic force microscope (AFM). The steel studied was prepared using grit papers with different abrasive particle sizes (#600, #1500, #2000) and exposed to artificial seawater for 4 h. A power spectral density (PSD) approach, which considered lateral distribution of surface roughness, was used to compare with traditional statistical roughness parameters. According to the roughness evolution, the corrosion susceptibility was #600 > #1500 > #2000, indicating greater corrosion resistance for smoother surfaces. The calculus carried out for estimating the corrosion rate as function roughness variation dictates that there may be up to three stages in the onset of corrosion. The first and third stages show a low corrosion rate (considerably less than 4 ×10−6 A/cm2), while the middle stage reflects an accelerated corrosion rate (up to 5.3 ×10−5 A/cm2 for #600 at 2 h). These results were in concordance with conventional electrochemical impedance spectroscopy tests. This method is proposed as a preventive strategy for the assessment of pipeline materials integrity which are used for transporting petroleum industry products.

Corrosion and aging risk assessment of an injection system for FCC/Bio-oil co-feed

Fast pyrolysis oil (FPO) is a renewable biocrude with high corrosivity and poor thermal stability. Co-processing FPO with petroleum intermediates in existing fluid catalytic cracking (FCC) units is one of the most applicable methods for transforming low-quality biocrudes into drop-in fuels. Although FPO is immiscible with petroleum intermediates, co-processing can be achieved using two separate feeding lines for FCC injection instead of the premixture. However, the corrosion of structural materials and the thermal stability of FPO pose significant challenges to the co-processing feed injection system, as the feedstocks are usually preheated to 100–300 °C prior to injection. This study focuses on the corrosion of stainless steel (SS) 316L and evaluates the aging risk of FPO at a temperature range of 80–220 °C. SS 316L experienced noticeable degradation with increasing temperature. Corrosion rates of 0.06, 0.62, and 1.77 mm/y were observed at 80, 150 and 220 °C, respectively. The experimental observation also reveals phase separation (liquid and solid phase) of FPO at the experimenting temperatures. However, the change in the physicochemical properties of the phases becomes more significant as temperature increases. Furthermore, a critical temperature of about 80 °C was identified, which signifies both the onset of active corrosion of SS 316 L in FPO and the fast aging of FPO.

Development of Reliable Accelerated Corrosion Tests for Aluminum Alloys Used in the Aerospace Industry

Aluminum alloys are not immune to corrosion which can take the form of localized corrosion. Thus, the assessment of the corrosion behavior of aluminum alloys under atmospheric conditions is a major topic for the aerospace industry. One major difficulty in this task is the lack of robust and reliable accelerated corrosion test(s) in this field. Indeed, several tests as the neutral salt spray test (ASTM B117) are used to assess the general corrosion resistance of aluminum, but these tests were not developed specifically for the aerospace industry and are not representative of service conditions. The aim of the present study was to compare the results of various accelerated corrosion test conditions (ASTM B117, VDA 233-102, Volvo STD 423-0014) with newly developed test conditions. Hence, different accelerated corrosion tests were designed by varying several parameters in the Volvo STD 423-0014 such as the salt concentration, time of wetness, and relative humidity. The results obtained on eight aluminum alloys (2xxx, 7xxx, and Al-Li alloys) were then compared to marine exposures. From the results, one test provides the same type of corrosion attacks on the different alloys under atmospheric exposures in the marine site and a good acceleration factor.

Microstructure and corrosion behavior of welded joint between 2507 super duplex stainless steel and E690 low alloy steel

Microstructure and corrosion behavior of welded joints between super duplex stainless steel 2507 and low alloy steel E690 were characterized herein. The joints are composed of base metal and heat affected zone (HAZ) of the two steels, weld metal, and dilution zone at the interface between weld metal and HAZ of E690 steel. Concentration gradients of Fe, Ni, Cr, and Mo exist between fusion boundary and Type-II boundary, and martensite band with a high hardness is formed. The changes of microstructure, element diffusion in different regions, and local acidification in E690 HAZ lead to heterogeneous corrosion attacks on the welded joints in artificial seawater. After long-term exposure, a corrosion groove is generated at the HAZ of E690 adjacent to the interface, where high stress corrosion cracking vulnerability is expected.

Investigation on the Effect of a Chromium-Free Sealing Treatment for the Corrosion Resistance of AA2198-T851 after Tartaric Sulphuric Anodizing (TSA)

The AA 2198-T851 is a third-generation Al-Li alloy developed for use in the aircraft industry. Al-Li alloys are susceptible to localized corrosion due to their complex microstructure resulting from the used thermomechanical treatment. In order to prevent localized corrosion, these alloys are usually protected by anodizing in order to avoid a corrosive environment. Subsequently, for anodizing, a sealing treatment is usually performed for parts. Some sealing treatments use hexavalent-chromium-ion-containing solutions. In this investigation, a chromium-free sealing treatment in a solution with cerium ions has been carried out, and the effect on the corrosion resistance of the AA2198-T851 alloy was investigated. Hydrothermally sealed or unsealed samples were also tested for corrosion resistance for comparison reasons. The corrosion resistance of the anodized aluminum alloy, either hydrothermally sealed or in a cerium-ion-containing solution, was evaluated in a sodium chloride solution by electrochemical impedance spectroscopy as a function of immersion time. The samples sealed in a cerium-containing solution increased their corrosion resistance when compared to the hydrothermally sealed. The effectiveness of the sealing process with cerium that was observed in the electrochemical tests indicated that after the corrosive attack of the barrier layer, there was a “sealing” process of the sample surface.

Anticorrosion performance of 1–benzylimidazole and synergistic iodide additives on C1018 carbon steel in 15% HCl solution

Acidizing, an industrial practice to enhance petroleum recovery, causes one of the most severe corrosion attacks on carbon steel drilling pipelines. Identifying highly efficient inhibitors to ameliorate this phenomenon is important for the petroleum industry. Here, the performance of 1–benzylimidazole (BZM) as a corrosion inhibitor for C1018 carbon steel in 15% HCl was investigated using electrochemical, weight loss and surface characterization techniques. Results from electrochemical techniques (electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), linear polarization resistance (LPR) and potentiodynamic polarization (PDP)) agree that BZM performs efficiently by providing inhibition efficiency up to 75% at 25 °C with 1200 ppm concentration. The addition of 5 mM KI significantly enhances BZM efficiency to 93% at 25 °C. BZM alone is a mixed–type corrosion inhibitor with slightly anodic behavior. The addition of KI transforms the BZM inhibition mechanism more cathodically. However, the BZM + KI efficiency decreases to 60% at 60 °C. Surface characterization by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) confirm that BZM uses its nitrogen and phenyl groups to adsorb on the steel surface, forming a thin film which mitigates localized corrosion.

Barkhausen Noise Emission as a Function of Tensile Stress in Low-Alloyed Steels: Influence of Corrosion and Steel Strength

Components of civil buildings are frequently made of low-alloyed steel, which can suffer from corrosion damage. This damage reduces their bearing capacity and/or redistributes the load to neighboring regions with the potential risk of their collapse. For this reason, this study deals with the non-destructive monitoring of bodies made of these steels based on Barkhausen noise emission. The superimposing contribution of corrosion extent and exerted tensile load is investigated on samples of variable yield strength in the range from 235 to 1100 MPa. It is found that the presence of a corroded layer attenuates Barkhausen noise and makes the body harder from a magnetic point of view. The reduced effective thickness of the samples as a result of corrosion damage increases the true stress. Barkhausen noise grows along with the tensile stress in the direction of exerted stress at the expense of decreasing Barkhausen noise in the perpendicular direction. The evolution of Barkhausen noise versus tensile stress is mostly shifted to the lower values of Barkhausen noise, along with the increasing degree of corrosion damage. The evolution of Barkhausen noise versus tensile stress is also affected by the initial microstructure and the corresponding yield strength of the low-alloyed steel. Corrosion attack results in the growth of FWHM, which is compensated by the decreasing evolution along with the tensile stresses. The effective values drop down with the higher extent of corrosion damage. However, the response with respect to the tensile stress is asymmetric in RD and TD due to the realignment of DWs into RD. Finally, PP tends to increase with the corrosion attack as well as the tensile stress and this parameter only exhibits the systematic behavior in RD as well as TD. On the other hand, MBN-extracted parameters as well as their combination provide no exclusive values on which the pure contribution of corrosion and tensile stress can be distinguished.

Impact of O2 Content on the Corrosion Behavior of X65 Mild Steel in the Gaseous, Liquid, and Supercritical CO2 Streams

The CO2 stream in a carbon capture utilization and storage application generally includes impurities that could cause internal corrosion of CO2 pipelines. The general and localized corrosion behavior with a variety of O2 concentrations for X65 mild steel both in water-saturated CO2 and CO2-saturated water environments was evaluated using an autoclave. Corrosion tests were performed at 8 MPa and 25°C, 8 MPa and 35°C, and 4 MPa and 35°C to simulate the liquid, supercritical, and gaseous CO2 transportation. Results indicate that notably higher general corrosion rates were recorded at each O2 concentration in the CO2-saturated water phase than those in the water-saturated CO2 environment. The general corrosion rates did not show gradual rise at 0 ppm to 2,000 ppm of O2; instead, a maximum was measured at 1,000 ppm of O2 at 8 MPa and 25°C, and 50 ppm O2 at 8 MPa and 35°C in the water-saturated CO2 environment and 50 ppm at 8 MPa and 25°C, and 100 ppm at 8 MPa and 35°C in the CO2-saturated water environment. The general corrosion rate at 4 MPa and 35°C followed a different changing trend with O2 content from that in 8 MPa, and 25°C and 35°C both in the water-saturated CO2 and the CO2-saturated water environments. Localized corrosion or an average corrosion rate of beyond 0.1 mm/y was identified in each test in the CO2-saturated water environment. When O2 was introduced, a more porous corrosion product scale was detected on the coupon surfaces. A final series of corrosion tests with 100 ppm and 2,000 ppm O2 and 60% and 80% relative humidity in a CO2 environment did not show any sign of localized corrosion attack, and the average corrosion rates were below 0.1 mm/y at 8 MPa, 25°C and 35°C, and 4 MPa and 35°C.

Towards weathering and corrosion resistant, self-warning and self-healing epoxy coatings with tannic acid loaded nanocontainers

In this work, an active protective epoxy coating with weathering resistant, corrosion-warning, and self-healing properties was developed by incorporating tannic acid (TA) loaded mesoporous silica (MSN-TA) nanocontainers. The introduction of MSN-TA nanocontainers could alleviate the coating degradation via scavenging the radicals generated during UV irradiation. Compared with the blank coating, the coating containing 5 wt.% MSN-TA nanocontainers exhibited much less degradation in surface morphology, wettability and glossiness, and maintained a good barrier property after 384 h of accelerated weathering. Once the coating was damaged, the released TA could react with the Fe3+ ions to form a chelate that endowed the coating scratch with a visible black coloration, i.e. triggering a self-warning capability to indicate the initial onset of corrosion. In addition, the generated chelate could inhibit extensive corrosion propagation, offering a significant self-healing effect demonstrated by the stabilized impedance modulus values during 28 days of immersion in NaCl solution.

Effect of Functional Nanoporous TiO2 Film Obtained on Ti6Al4V Implant Alloy to Improve Resistance in Biological Solution for Inflammatory Conditions.

The metallic titanium-based biomaterials are sensitive to corrosion-induced degradation in biological fluids in the presence of inflammatory conditions containing reactive oxygen species (ROS). Excess ROS induces oxidative modification of cellular macromolecules, inhibits protein function, and promotes cell death. In addition, ROS could promote implant degradation by accelerating the corrosive attack of biological fluids. The functional nanoporous titanium oxide film is obtained on titanium alloy to study the effect on implant reactivity in biological fluid with reactive oxygen species such as hydrogen peroxide, which are present in inflammations. The TiO2 nanoporous film is obtained by electrochemical oxidation at high potential. The untreated Ti6Al4V implant alloy and nanoporous titanium oxide film are comparatively evaluated for corrosion resistance in biological solution by Hank's and Hank's doped with hydrogen peroxide by electrochemical methods. The results showed that the presence of the anodic layer significantly improved the resistance of the titanium alloy to corrosion-induced degradation in biological solutions under inflammatory conditions.

Hybrid Zinc Coatings with Chitosan/Alginate Encapsulated CuO-Nanoparticles for Anticorrosion and Antifouling Protection of Mild Steel

The construction of anticorrosion coatings containing antifouling agents is an effective way to ensure the long-term durability of marine steel infrastructures. In this work, an innovative hybrid coating was prepared by introducing biocide CuO nanoparticles in ordinary zinc coating to improve its protective ability for steel in aggressive salt water environments. The CuO nanoparticles were embedded inside the matrix of chitosan/alginate complexes to prevent spontaneous copper leaching during corrosive attacks. Two procedures were applied for the electrodeposition of hybrid/composite zinc-based coatings on low-carbon steel substrates (DC current): first—the co-electrodeposition of encapsulated CuO nanoparticles with zinc on a cathode (steel) electrode from a sulfate electrolyte with a relatively low pH value of about 4.5–5.0 and second—the encapsulated CuO nanoparticles were electrodeposited from aqueous solution as an intermediate layer between two zinc deposits. The particles size and stability of suspensions were evaluated using dynamic light scattering. Both hybrid coatings were compared in terms of surface morphology and hydrophilicity (SEM and AFM analysis, contact angle measurement) and corrosion resistance (potentiodynamic polarization curves, polarization resistance). The protective characteristics of the coatings were compared in a 3.5% NaCl solution and artificial sea water. The hybrid coating showed 2–4 times higher polarization resistance than the bare zinc coating during a 30 day immersion in artificial sea water, indicating that this coating has the necessary characteristics to be used in a marine environment.

Corrosion behavior and mechanism of 4004/Al-Mn-Cu-Mg-Si/4004 aluminum brazing sheet in sea water acidified accelerated test

The microstructure and corrosion properties of a novel 4004/Al-Mn-Cu-Mg-Si/4004 aluminum brazing sheet were investigated in comparison with the traditional 4004/3003/4004. It revealed that, the microstructure after brazing of two aluminum brazing sheets from outer to center were both residual Al-Si eutectic, precipitate-free zone (PFZ), band of dense precipitates (BDP) and core material, respectively. However, the alloying element distribution and the types and amounts of second phases were quite different. The sea water acidified accelerated test showed that 4004/Al-Mn-Cu-Mg-Si/4004 exhibited typical exfoliation corrosion, while the corrosion quickly spread deep into the core material of 4004/3003/4004. The formation of Cu concentration gradient and the strip distribution of Al-Mg-Cu-Si precipitates in the BDP region contributed to the exfoliation corrosion of 4004/Al-Mn-Cu-Mg-Si/4004. The corrosion behaviors of Al-Mn-Cu-Mg-Si and AA3003 core materials are both in form of intergranular corrosion (IGC)，and the later was more severe than the former. For Al-Mn-Cu-Mg-Si core material, high-density fine dispersed cathodic α-Al(Mn, Cu)Si precipitates promoted the formation of a profusion of micro-galvanic cells in the Al matrix, which would retard any effects between the grain boundary precipitations and the adjacent relatively PFZs. Hence, the IGC susceptibility of Al-Mn-Cu-Mg-Si core material was decreased. Besides, less large-sized α-AlFeMn(Cu)Si phases in core material also reduced the localized corrosion attack. At last, the corrosion in depth direction of 4004/Al-Mn-Cu-Mg-Si/4004 was retarded, compared to its counterpart.

A comprehensive review on synergistic and individual effects of erosion–corrosion in ferrous piping materials

Abstract The degradation of materials due to erosion–corrosion occurs on the components that handle particle-laden corrosive slurry. The combined attack of mechanical erosion and corrosion shows increased material loss than the individual action of erosion and corrosion. The synergy accelerates material removal by eroding the corroded surface layer and corroding the surface due to the elimination of the passivating oxide layer by erosion. The synergism of erosion–corrosion is found to be more complex. Further, the coupled effect of mechanical erosion and electrochemical corrosion and the factors influencing erosion–corrosion still needs to be fully investigated. This review aims to provide a general and detailed summary of the interaction between erosion and corrosion of materials for the applications of pump impellers, pipelines for desalination, and oil and gas transportation. Importance is also given to the factors influencing erosion–corrosion, such as erodent particle properties (hardness, size, and shape), slurry properties (particle concentration, pH value, temperature), and flow characteristics (impingement angle, velocity). The various erosion models and the most used apparatus have also been reviewed.

Self-assembly of exfoliated graphene flakes as anticorrosive coatings for additive manufactured steels

This study demonstrates the feasibility of using liquid exfoliation of expandable graphite into multilayer exfoliated graphene flakes (EGFs) to form a self-assembled thin film on an air–water interface. The film can coat the surface of additive manufactured (AM) steel substrates to enhance surface properties, specifically AM 316 stainless-steel (AM316), AM 8620 steel (AM8620), and samples of the same alloys made by conventional manufacturing (CM) processes. Liquid exfoliation offers a high yield route for an EGF coating that can cover up to 95% of the sample surface with a single application. The thin, flexible EGFs can coat a rough AM metal surface, while the highly intact crystal lattice protects covered areas against diffusing ions and prevents localized corrosion compared to similar coatings made with graphene oxide (GO) or reduced GO (rGO). The EGF coating exploits a unique self-assembly process without surfactants or stabilizers, wherein the hydrophobicity and hydrophilicity of EGFs arrange the flakes, then van der Waals (vdW) forces bond them together and to the substrate for a coherent anti-corrosive coating. Electrochemical measurements indicate lower corrosion potential for coated samples, nanoindentation measurements show surface hardness protection against corrosive attack, and weight loss measurements demonstrate long-term protective capabilities. Density functional theory calculations, using the optB88-vdW exchange functional of the graphene and iron (111) interface demonstrated stronger binding and shorter interface distance compared to the well-studied graphene/nickel (111) interface. These calculations and experimental results can further elucidate the superior performance of EGF thin film coatings on high iron content steels, especially AM steels.

Self-repairing functionality and corrosion resistance of in-situ Mg-Al LDH film on Al-alloyed AZ31 surface

A novel Mg-Al LDH film was in-situ prepared hydrothermally in an alkaline aqueous solution on an Al-alloyed AZ31 substrate. The structural, chemical and functional characteristics of the film were explored by means of scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), polarization curve, AC impedance and salt immersion tests, respectively. The anti-corrosion results indicated that the Mg-Al LDH film on the Al-alloyed AZ31 surface could effectively protect the AZ31 from corrosion attack even after 90 days of immersion in 3.5 wt.% NaCl solution. The protection performance is surprisingly better than most of the reported coatings on Mg alloys. More interestingly, when the Mg-Al LDH film was scratched, the exposed Al-alloyed surface might gradually release metal ions and re-generate dense LDH nano-sheets in the corrosive environment to inhibit the further corrosion there, exhibiting a self-repairing behavior. The combination of the benign long-term protection and desirable self-repairing performance in this new process of surface-alloying and LDH-formation may significantly extend the practical application of magnesium alloys.

Mixed reaction gold as versatile plating solution for ENIG, ENEPIG and EPAG plating

The surface finish on a printed circuit board (PCB) or substrate serves as surface protection and at the same time enables a variety of assembly techniques. Depending on which final finish is selected it allows for e.g. soldering connections or wire bonding by Al, Au or even Cu-wires. Surface finishes are typically characterized by different metal layers, including tin, nickel, palladium or gold. In this context the electroless or immersion plating of gold has a long history in the electronics industry. The gold plating represents a key step in different finish systems such as electroless nickel/immersion gold (ENIG), electroless nickel/electroless palladium/immersion gold (ENEPIG) and electroless palladium/autocatalytic gold (EPAG). ENIG, ENEPIG and EPAG finishes are characterized by their capabilities to be used as solderable and wire-bondable finish with specific benefits for ENEPIG and EPAG such as enhanced solder joint reliability and gold-wire bondability. In this paper an overview is given on the different types of electroless gold plating electrolytes from fully immersion type and autocatalytic type to mixed reaction type gold electrolytes. The details of the various plating mechanisms are presented, and the different properties and capabilities of these electrolytes are compared and explained based on the respective mechanisms. The presented study investigates the performance of a gold electrolyte of a mixed reaction type looking into the layer properties as well as the soldering and bonding capabilities. The results show that a mixed reaction gold electrolyte can be capable for versatile application- ENIG, ENEPIG and EPAG. The capability of the process was tested with respect to the solder wetting performance, solder joint reliability, wire bonding performance, corrosive attack to the nickel and thickness distribution. It can be shown that this gold process passes or exceeds all related industry standards and target requirements for ENIG, ENEPIG and EPAG final finishes.

Use of Electron Microscopy in the Analysis of the Influence of Roughness on the Corrosion Behavior of Selected Ti Alloys

Titanium alloys are among the biocompatible materials that are used for biomedical implants. From the point of view of the reactivity of the human body, it is important to know the state of the surface of these materials, which in technical practice is represented by the term surface integrity, which includes a complex of evaluated properties. One of the classic approaches is the evaluation of the surface roughness and the properties of the stable oxide layer, which influence the formation of the connection of the implant with human tissues and influence its acceptance. Another frequent approach is the use of optical metallography, especially for the assessment of material thickness, distribution and character of corrosion attack. Less common is the use of electron microscopy in the evaluation of the surface, which in this case is affected by the action of corrosion. Samples of both pure titanium and Ti6Al4V alloy were divided into sets according to surface roughness and subsequently exposed to corrosion for different periods of time. The presented article is devoted to basic analyzes of the effect of roughness on corrosion behavior using not only classical optical but also electron microscopy.