Arc Oxidation Research Articles

Surface modification of WE43 Mg alloy via combination of cold spray and micro-arc oxidation for wear related applications at high temperatures

This study investigates the high temperature wear behaviour of a WE43 Mg alloy after covering it with single and dual layer coatings. For this purpose, cold spray and micro-arc oxidation processes were employed individually and sequentially. Single-layer coatings fabricated by cold spray and micro-arc oxidation processes were Al/Al2O3 composite and MgO-based ceramic, respectively. Sequential application of cold spray and micro arc oxidation processes induced dual layer coating upon synthesizing an external Al2O3–based layer over the Al/Al2O3 composite layer. Results of the wear tests conducted under the load of 2 N revealed the superior resistance of the dual layer coated sample against the rubbing action of the counterface compared to single layer coatings. Thus, the presence of a relatively hard and tough external Al2O3-based layer over the Al/Al2O3 composite layer sustained protection up to the temperature of 320 °C, where the dominant wear mechanism was fatigue wear. However, the increase in the test temperature to 350 °C caused detachment of the external Al2O3-based layer. Reduction of the wear test load from 2 to 1 N resulted in the remaining of external Al2O3-based layer intact with the underlying Al/Al2O3 composite layer even at a test temperature of 350 °C. It is therefore concluded that the combination of cold spray and micro-arc oxidation processes is promising to broaden the reliable use of WE43 and other Mg alloys in wear related applications at high service temperatures.

Corrigendum to: “Recent Patents of Micro-arc Oxidation Technology”

A typographical error appeared in terms of repetition of sentences in the manuscript titled “Recent Patents of Micro-arc Oxidation Technology”, 2024; 18(6): e300423216386 [1]. <p> Original: Liu et al. [90] provided a method for micro-arc oxidation of electrolytes and reducing the brittleness of microporous ceramic film. By adding chitin nanowhiskers and Nacetylated chitosan into the electrolyte, the toughness of the ceramic film is improved, and bending brittleness and fragmentation are prevented. <p> Li et al. [91] provided an electrolyte for micro arc oxidation self-lubricating composite ceramic coating. The friction and wear properties of the composite ceramic coating were improved by adding nano additives and micro MoS2 powder into the conventional electrolyte. <p> Liu et al. [90] provided a method for micro-arc oxidation of electrolytes and reducing the brittleness of microporous ceramic film. By adding chitin nanowhiskers and Nacetylated chitosan into the electrolyte, the toughness of the ceramic film is improved, and bending brittleness and fragmentation are prevented. <p> Li et al. [91] provided an electrolyte for micro arc oxidation self-lubricating composite ceramic coating. The friction and wear properties of the composite ceramic coating were improved by adding nano additives and micro MoS2 powder into the conventional electrolyte. <p> Corrected: Liu et al. [90] provided a method for micro-arc oxidation of electrolytes and reducing the brittleness of microporous ceramic film. By adding chitin nanowhiskers and Nacetylated chitosan into the electrolyte, the toughness of the ceramic film is improved, and bending brittleness and fragmentation are prevented. <p> Li et al. [91] provided an electrolyte for micro arc oxidation self-lubricating composite ceramic coating. The friction and wear properties of the composite ceramic coating were improved by adding nano additives and micro MoS2 powder into the conventional electrolyte. <p> The original article can be found online at https://www.eurekaselect.com/article/131347

Study on the coating-formation process of micro arc oxidation coating on AZ31B magnesium alloy with Sc(NO3)3 addition

To investigate the effect of the addition of Sc(NO3)3 on the coating-formation process of AZ31B magnesium alloy MAO coating, microarc oxidation was conducted in a silicate-phosphate electrolyte containing 0.5 g/L Sc(NO3)3 for 15 s, 30 s, 60 s, 120 s, 240 s, and 1800 s. The oxidation voltage, surface morphology, and phase composition of the coatings were characterized using SEM, XRD, and XPS. The results indicated that Sc(NO3)3 hydrolytic complexation forms Sc(OH)2+ which leads to more uniform discharge micropores on the MAO coating surface, increasing the oxidation voltage. Compared to the MAO sample without Sc(NO3)3, the coating surface becomes denser and smoother. The MAO coating phase composition is MgO and Mg2SiO4, with Sc present as Sc2O3 in the coating.

A grey relational analysis of the micro arc oxidation process parameters and their effects on Ti-6Al-7Nb coating performance and corrosion resistance for biomedical uses

Abstract In current investigation micro arc oxidation of Ti6Al7Nb alloy was done to improve its surface properties and corrosion resistance. Mixture of Na2SiO3, Na3PO412H2O and KOH is used as electrolyte. MAO treated Ti6Al7Nb specimens were examined using x-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM) to examine their morphology and phase composition. It was observed that electrolyte composition is simultaneously included in the growing oxide layer during MAO process. From electrochemical study it was found that corrosion resistance of the Ti6Al7Nb increases during EIS testing in 0.9% NaCl solution. It was found that frequency, duty cycle, current and processing time effect the surface roughness, thickness, hardness and corrosion resistance of coating. Out of above mention parameters frequency and duty cycle has major impact on performance parameters. The objective of current investigation is to find out effects MAO process parameters on coating performance parameters such as coating thickness, hardness, surface roughness and corrosion resistance. At duty cycle of 50%, frequency 500 Hz, current 300 mA and processing duration 7.5 min, highest coating thickness 32.96 μm and surface roughness 3.3680 μm was obtained. Process parameters have the influence on pore size, biggest average pore size 3.8519 μm was obtained at duty cycle of 50%, frequency 500 Hz, current 300 mA and processing duration 7.5 min. Grey relational analysis is done to determine which process variable has the most influence on performance parameters. From grey relational analysis technique, it was observed that duty cycle 50%, frequency 500 Hz, current 300 mA, and processing time 7.5 min are ideal process parameters for higher coating thickness, hardness, surface roughness and better corrosion resistance. From grey relation analysis it was also found that frequency has most significant impact on performance parameters after that duty cycle, then current and at last processing time.

Hierarchical nickel phosphide/carbon nanofibers for high performance pseudocapacitors

Nickel phosphide (Ni3P)/Carbon nanofibers (CNFs) with controllable sizes and morphologies are synthesized using micro arc oxidation method combined with thermochemical vapor deposition, with adjustment of different annealing temperatures to control the dimension of CNFs. In this study, we report the in situ formation of transition metal phosphide nanoparticles through the conversion of 1D Ni5TiO7 nanowires. This fabrication strategy ensures the high growth density of CNFs. The initially formed Ni3P nanoparticles boost the catalytic growth of CNFs, which feature a high specific surface area and excellent conductivity. Together with redox electrolyte, the specific capacitance of Ni3P/CNFs based pseudocapacitor (PC) is 114.6 mF cm−2 at a scan rate of 10 mV s−1 and maintains 95.0 % of initial capacity after 10,000 cyclic charging/discharging test. Moreover, such composite based symmetric PCs offer an energy density of as high as 31.6 Wh kg−1 accompanied with a power density of 10.3 kW kg−1. The performance of formed PC devices is comparable to market-available (Li-/Na-) batteries. Therefore, Ni3P/CNFs composite film is a suitable capacitor electrode material for constructing high performance symmetric carbon material based PCs.

Optimizing bio-functional properties of Ti–Cu bone implants through introducing hierarchical structures

Titanium-copper alloys are attracting interest for biological applications, but are still limited by the instinctive bioinertness of the material processed by conventional methods, which limits their application as potential bone implants. In this work, the hierarchical structures of porous Ti–Cu implants, which contain typical micro/nano sub-porous structure on the surface was successfully developed with the combination of the novel additive manufacture of laser powder bed fusion (L-PBF) and subsequent the micro arc oxidation (MAO) treatment. The high roughness, excellent hydrophilicity and the good match of mechanical properties were found on the micro/nano porous surface. And several compounds including TiO2-A, TiO2-R, CuO and Cu2O were also formed on the MAO-treated surface, which are all beneficial for the effectiveness improvement as biomaterials. The biological results conformed the obvious improvements in gain-of-function (GoF) of antibacterial properties and biological performances. All the samples for cell experiments exhibited a certain antibacterial function, in which no cytotoxicity and a significant promotion of the early adhesion for the MC3T3-E1 cells and BMSCs were detected in the MAO-treated samples.

Recent Patents of Micro-arc Oxidation Technology

Abstract: Micro-arc oxidation (MAO) is a new surface treatment technology that can improve wear resistance, corrosion resistance, high voltage insulation, and other metal properties. Therefore, this technology is widely used in automobile manufacturing, aerospace, ship anti-corrosion, medical equipment, sewage treatment, and other fields. This paper reviews the representative patents of micro-arc oxidation technology at home and abroad. The micro-arc oxidation processing device, the process method of micro-arc oxidation processing, the power supply and electrical parameters of micro-arc oxidation, the preparation of electrolytes, and the methods of anticorrosion and protection of metal surface are analyzed. The development trend of micro-arc oxidation technology in the future is discussed. Micro-arc oxidation is a simple, green, and environment- friendly surface treatment technology, and there will be more patents in the field of micro- arc oxidation in the future.

Self-lubricating properties of Al2O3/MoS2/CePO4 composite layers in-situ prepared by micro arc oxidation on 6082-T6 alloy

Al2O3/MoS2/CePO4 composite ceramic layer was in-situ prepared on aluminum alloy by micro-arc oxidation. The results show that the content of (CH3CO3)3Ce·xH2O has a great influence on the microstructure of the ceramic layer. When the addition amount is 7.5 g/L, the surface hardness of the ceramic layer is 961.97 HV1, which is 1.8 times that of the unadded and 8.36 times that of the matrix. Tribological tests show that the moderate addition of (CH3CO3)3Ce·xH2O also significantly improves the wear resistance of the ceramic layer. Composite layer research can be developed and applied to other alloys to improve their friction properties.

Effect of the alloying element Sc and Zr in 5B70 Al alloy on the microstructure, toughness and tribological properties of MAO ceramic film

The existence form of alloying element Sc and Zr in the micro arc oxidation (MAO) ceramic film on 5B70 Al alloy and their effects on the microstructure, fracture toughness, and tribological properties of the MAO ceramic film was investigated. The findings suggested that the Zr element primarily existed in the form of ZrO2, distributed around the Al2O3 phase. The Sc element remained spherical and dispersed in the form of Al3Sc in the ceramic film. The synergistic effect of ZrO2 and Al3Sc significantly improved the hardness, fracture toughness, and wear resistance of the dense layer in MAO ceramic film on 5B70 Al alloy. This provided theoretical basis and technical support for the development of high-performance MAO composite films on Al alloy surfaces.

Effect of electrolyte pH value on microstructure and corrosion resistance of black MAO coating on 6063 aluminum alloy

Black micro-arc oxidation (MAO) coatings were obtained on the surface of 6063 aluminum alloy by using the MAO technique in silicate electrolyte with colorant NH4VO3. The work aimed to study the effect of adjusting the electrolyte pH (pH10, pH11, pH12, and pH13) on the microstructure, mechanical properties, and corrosion resistance of black MAO coatings on 6063 aluminum alloy. The experimental results showed that the electrolyte pH had an important effect on the macroscopic morphology of the MAO coatings. As the electrolyte pH value increased, the process voltage of the sample decreased, the duration of the anodic oxidation stage and the spark discharge stage were shortened, while the duration of the micro arc oxidation stage was prolonged. Reasonable adjustment of the electrolyte pH could reduce the poriness and defects of the coatings, decrease the surface roughness of the coatings, and improve the quality and wear resistance of the coatings. The corrosion resistance of the black MAO coating obtained in the electrolyte with pH12 was superior and the corrosion current density was only 3.207×10−7 A/cm2. The immersion corrosion test further demonstrated the same results of corrosion resistance.

A surface and corrosion characterisation of micro arc oxidation treated friction stir welded ZM21 and ZE41 magnesium alloy: a comparison study

Magnesium alloys have gained attention as promising materials in industrial applications, for their high specific strength and low density. Magnesium alloys have desirable mechanical properties, but their poor corrosion resistance prevents their safe implementation. Alloys such as ZM21 and ZE41, possess unique properties that provide improved machinability and increased red-hot strength, respectively, while remaining prone to corrosion. To improve corrosion resistance, surface treatments and coating processes are employed. Comparing the corrosion characteristics of ZM21 and ZE41 is vital for aerospace and automotive applications, directly affecting component durability, reliability, and performance against corrosion. Magnesium alloys are frequently joined through friction stir welding (FSW), hence, similar importance is provided to studying the corrosion performance of welds, since FSW introduces microstructural changes that alter corrosion performance of welded joints. The paper discusses electrochemical corrosion mechanisms and analyzes the effect of Micro Arc Oxidation (MAO) coating on electrode potential, passivity, and electrical resistance of ZM21 and ZE41 plates welded through FSW. MAO treatments were performed on both base material and FSW joints. The corrosion performance of MAO-coated FSWed ZM21 and ZE41 alloys was compared through the Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Polarisation (PDP) tests. The PDP test revealed that MAO treatment enhanced the corrosion resistance of both base and FSWed ZM21 and ZE41 magnesium alloys. There was an improvement in potential polarization (Rp) values from 565 Ω cm2 to 11245 Ω cm2 for ZM21 and from 1184.4 Ω cm2 to 11435.69 Ω cm2 for ZE41 alloys. While exhibiting improvements in corrosion resistance, MAO-treated ZE41 performed better than MAO-treated ZM21. PDP results were verified through confirmatory EIS results. Therefore, MAO treatments are effective methods to improve the corrosion performance of Mg alloys. Evaluation of MAO coating performance on various FSW Mg alloys and studying their corrosion performance is crucial for engineering material selection.

Alfalfa biomass as a green source for the synthesis of N,S-CDs via microwave treatment. Application as a nano sensor for nifuroxazide in formulations and gastric juice

BackgroundResearchers have investigated different techniques for synthesis of carbon dots. These techniques include Arc discharge, laser ablation, oxidation, water/solvothermal, and chemical vapor deposition. However, these techniques suffer from some limitations like the utilization of gaseous charged particles, high current, high temperature, potent oxidizing agents, non-environmentally friendly carbon sources, and the generation of uneven particle size. Therefore, there was a significant demand for the adoption of a new technology that combines the environmentally friendly aspects of both bio-based carbon sourcing and synthesis technique. ResultsMedicago sativa L (alfalfa)-derived N, S-CDs have been successfully synthesized via microwave irradiation. The N,S-CDs exhibit strong fluorescence (λex/em of 320/420 nm) with fluorescence quantum yield of 2.2 % and high-water solubility. The produced N,S-CDs were characterized using TEM, EDX, Zeta potential analysis, IR, UV–Visible, and fluorescence spectroscopy. The average diameter of the produced N, S-CDs was 4.01 ± 1.2 nm, and the Zeta potential was −24.5 ± 6.63 mv. The stability of the produced nano sensors was also confirmed over wide pH range, long time, and in presence of different ions. The synthesized N, S-CDs were employed to quantify the antibacterial drug, nifuroxazide (NFZ), by fluorescence quenching via inner filter effect mechanism. The method was linear with NFZ concentration ranging from 1.0 to 30.0 μM. LOD and LOQ were 0.16 and 0.49 μM, respectively. The method was applied to quantify NFZ in simulated gastric juice (SGJ) with % recovery 99.59 ± 1.4 in addition to pharmaceutical dosage forms with % recovery 98.75 ± 0.61 for Antinal Capsules® and 100.63 ± 1.54 for Antinal suspension®. The Method validation was performed in compliance with the criteria outlined by ICH. Significance and noveltyThe suggested approach primarily centers on the first-time use of alfalfa, an ecologically sustainable source of dopped-CDs, and a cost-effective synthesis technique via microwave irradiation, which is characterized by low energy consumption, minimized reaction time, and the ability to control the size of the produced CDs. This is in line with the growing global recognition of the implementation of green analytical chemistry principles.

A Review of Research on Improving Wear Resistance of Titanium Alloys

Titanium alloy is widely used as oil drill pipe material because of its light weight, high strength, good toughness, corrosion resistance, fatigue resistance, and good process performance. However, due to its low hardness, poor wear resistance, serious oxidation at high temperature (700 °C), and difficulty in lubrication, in oil and gas field exploration and development drilling, especially in deep wells, high displacement wells, horizontal wells, and highly deviated wells, wear and tear are prone to occur. The application and development of titanium alloys are greatly limited. This paper introduces the research status of the common surface modification technologies of titanium alloys, such as laser cladding, magnetron sputtering, plasma spraying, micro arc oxidation, etc. It points out the improvement effect of various modification technologies on the wear resistance and high-temperature oxidation resistance of titanium alloys and discusses the advantages and disadvantages of various modification technologies. A proposed method for enhancing the wear resistance and high-temperature oxidation resistance of titanium alloys was finally introduced, and its potential for future development was investigated.

Friction and corrosion characteristics of microarc oxidation/laser cladding palygorskite coating on 6061 aluminum alloy substrates

In this study, micro arc oxidation (MAO) technology was used to surface coating of 6061 aluminum (Al) disk. Then laser is used to clad palygorskite (Pal) on the surface of the MAO coating to improve the protection of the coating against the Al substrate. The laser irradiates heat onto the Pal powder, the Pal is heated and at the same time the MAO coating is affected by the heat, and the MAO coating is cooled and cured along with the Pal to form the MAO- Pal composite coating. The surface morphology, elemental composition and phase composition of the MAO-Pal coating were analyzed using scanning electron microscopy, energy spectroscopy and X-ray diffraction. And friction experiments were performed on the MAO- Pal coating. The results showed that the coefficient of friction (COF) of the MAO-Pal coating was reduced by 27 % compared to the Al substrate and 19 % compared to the MAO coating under water lubrication conditions. Through the corrosion resistance experiments, the corrosion potential (Ecorr) of the MAO- Pal coating increased by 0.197 V compared to the Al substrate and 0.280 V compared to the MAO coating, and the corrosion current density (Icorr) simultaneously decreased by three orders of magnitude compared to the Al substrate and one order of magnitude compared to the MAO coating. The MAO- Pal coating prepared by laser cladding Pal had good wear and corrosion resistance, which improved the service life and application range of Al alloy and was expected to promote the development of Al alloy in the application field.

The influence of rolling on the corrosion and wear resistance of the MAO coating on ZM5 alloy

PurposeThe impact of rolling on the performance of micro arc oxidation (MAO) coatings on ZM5 alloy has been underreported. The purpose of this study is to explore the correlation between rolling and the failure mechanism of MAO coatings in greater depth.Design/methodology/approachThe influence of rolling on the corrosion and wear properties of MAO coating was investigated by phase structure, bond strength test (initial bond strength and wet adhesion), electrochemical impedance spectroscopy and wear test. The change of the surface electrochemical properties was studied by first principles analysis.FindingsThe results showed that the MAO coating on rolled alloy had better corrosion and wear resistance compared to cast alloy, although the structure and component content of two kinds of MAO coating are nearly identical. The difference in interface bonding between MAO coating and Mg substrate is the primary factor contributing to the disparity in performance between the two types of samples. Finally, the impact of the rolling process on MAO coating properties is explained through first-principle calculation.Originality/valueA comprehensive explanation of the impact of the rolling process on MAO coating properties will provide substantial support for enhancing the application of Mg alloy anticorrosion.Graphical abstract

Microstructure and properties of a MAO/PA/MoS2 composite coating formed on 6063 aluminum alloy by micro arc oxidation

Different self-sealing and lubricating composite coatings were produced on 6063 Al alloy using micro arc oxidation (MAO) with MoS2 and/or phytic acid (PA) incorporated into the base electrolyte. The tribological properties and electrochemical corrosion behavior of the coatings were detailed investigated in this paper. The results showed that the coefficient of frictional (CoF) of MAO/MoS2 coating decreased 29.6 % compared to that of the pure MAO coating due to the excellent self-lubricating of MoS2. Meanwhile, the CoF of MAO/PA/MoS2 coating reduced 39.5 % attributed to a thicker and more compact coating obtained by the addition of PA as an intermediate chelating agent besides the self-lubricating effect of MoS2 particles. The pores were sealed by MoS2 during MAO process due to the electrodeposition effect which resulted in a positive shifting of the corrosion potential. However, the improvement of corrosion resistance for the MAO/MoS2 coating was limited as the intrinsic defects in MoS2 lattice preferred to form micro galvanic cell. The corrosion current density of the MAO/PA/MoS2 coating was three orders of magnitude lower than that of pure MAO coating. The thin PA layer produced at the substrate/coating interface of the MAO/PA/MoS2 coating can act as a barrier to suppress the galvanic corrosion, inducing the best corrosion resistance of the coating.

Corrosion failure analysis and solutions of aluminum alloy gas path plate used in sanding device of high-speed train

During the maintenance of a high-speed train, it was frequently found that the anodized aluminum alloy gas path plates in the sanding device had different degrees of corrosion. In this paper, SEM, EDS, XRD and LAD-EDTEST spectrometer were used to analyze the macro and micro morphology, elements and phases of corrosion product, element compositions of the matrix and assembly problem of the gas path plates. The mechanism of delamination spalling corrosion caused by local pitting corrosion of anodized aluminum alloy gas path plate was described. In addition, the properties of the coatings produced by different surface treatment methods and different substrate materials were compared. The test results indicate that the corrosion protection level of the micro-arc oxide coating is higher than that of the anodic oxide coating, which is mainly composed of γ-Al2O3 and contains a certain amount of α-Al2O3. Compared with 2A12-T4 aluminum alloy, the micro arc oxidation (MAO) coating of 6082-T6 aluminum alloy has lower porosity, higher hardness, higher corrosion potential, lower corrosion current, and better corrosion resistance, and 6082-T6 aluminum alloy is more suitable for use as the gas plate material. Meanwhile, it is proposed that the MAO coating with 35 μm can obviously improve the corrosion resistance of the gas path plate.

Influence of graphene on corrosion properties of micro arc oxidation coatings on 7075 aluminum alloy

AbstractThis study uses 7075 aluminum alloy as the base material and employs micro arc oxidation technology to prepare ceramic coatings with different concentrations of graphene particles on the surface of the 7075 aluminum alloy. The effects of graphene particle concentration on micro arc oxidation behavior and coating performance were investigated through X‐ray diffraction, scanning electron microscope, electrochemical testing, and other performance characterization methods. The research results show that the addition of graphene particles helps to promote the transformation of metastable γ‐Al2O3 to stable α‐Al2O3, thereby enhancing the corrosion properties of the coating. When the concentration of graphene particles is 3 g/L, the prepared micro arc oxidation coating has the maximum thickness and hardness, which are 17.13 µm and 886.76 HV0.3, respectively, while the porosity and roughness are the smallest, which are .39 µm and 4.79%, respectively. Electrochemical test results show that the self‐corrosion current density is the smallest at this concentration, which is 2.323 × 10−9A/cm2. Therefore, the addition of graphene particles can effectively improve the corrosion properties of 7075 aluminum alloy.

A novel anti-corrosion and antibacterial integrated MAO/PCNZ composite coating on AZ31B Mg alloy

Magnesium and its alloys possess elastic modulus close to natural bone and degradable effects, making them widely applied in bone implantation. However, their rapid corrosion in a simulated body fluid restricts further application. This work firstly employs micro arc oxidation (MAO) technique to in situ grow a corrosion-resistant ceramic layer on the surface of AZ31B Mg alloy. Subsequently, nano ZnO particles are modified using a silane coupling agent and then incorporated into a poly(ε-caprolactone) coating with chitosan through a simple blending and micellar method to obtain the PCNZ composite coating. The chemical composition and micro structure are characterized by FTIR, XRD, SEM and AFM. Electrochemical tests and antibacterial experiments indicate that PCNZ composite coating exhibits excellent long-term corrosion resistance and certain antibacterial ability, demonstrating potential application in the field of bone implantation.

مقاومة غمر التأكل عند الصقل بالخردق وتطبيق الاكسدة الدقيقة عند 0.5% من النيتروجين مع اضافة سبيكة الماغنيسيوم AZ31 Mg

The effect of shot peening (SP) and Micro Arc Oxidation (MAO) were utilized to characterize the performance of the corrosion resistance process at 0.5 % Nt with add AZ31 Mg alloy. Hot rolling at different rolling speeds has been investigated in this work. The surface of the rolling materials a rolling speed of 4.7 m/min and the rolling materials a rolling speed of 10 m/min were measured to create a clear definition of corrosion resistance physical properties. Experimental results show the surface of the rolling materials a rolling speed of 4.7 m/min had higher surface smoothness values than the one of the rolling at 10 m/min. It was observed that the corrosion rate changed in the first 24 of 168 hours. In the following hours, the corrosion rate showed different results according to the initial microstructure properties of the base materials. Initially, pore size was the dominant factor determining corrosion resistance, although, after coating the corrosion rate was affected by the twins formed, based on rolling speed, which enhanced the corrosion rate between 24 and 168 hours. Keyword: Shot peening; micro arc oxidation; AZ31; Nd; hot rolling; corrosion resistance.