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The correlation between negative pulse and the black electrolyte properties of magnesium alloy micro-arc oxidation and the treated area was investigated by introducing a negative pulse electric field. The physical phase composition, microstructure, elemental distribution, and content of the coating were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The results showed that the introduction of negative pulses favored the generation of MgO and MgSiO3 contents in the coatings, and an increase in the MgO phase was found in the coatings formed in the failed electrolytes; the microporous size and microcracks of the coatings were gradually and significantly reduced; the average consumption of Cu ions was 0.0453 g/L·dm2, which is only 26% of that in the unipolar condition; the introduction of the negative pulses significantly improved the "anomalous consumption" of Cu ions. The introduction of negative pulse can significantly improve the "abnormal consumption" of copper ions, which is attributed to the change in the electric field by negative pulse, which makes the cathode-enriched Cu ions migrate to the anode and reduces the reduction and precipitation of Cu ions at the cathode. [ABSTRACT FROM AUTHOR]

The work addresses the issues of controllability of the microarc-oxidation process. This problem is mostly due to the difficulty of analytically characterizing the heterogeneous physical–chemical processes, which are nonlinear and nonstationary, that take place during microarc oxidation. To tackle this issue, a digital twin of the process is being developed, within which an analytical model is proposed to describe the behavior of the equivalent electrical circuit of the galvanic cell during coating deposition. The proposed analytical model of the process is nonlinear and nonstationary, which is attributed to the abrupt decrease in the active resistance of the coating during dielectric breakdowns. Based on experimentally obtained current and voltage oscillograms and the proposed analytical model, parametric identification of the electrical parameters of oxide coatings is performed using the matrix-operator method on the orthonormal Walsh basis. The matrix-operator method is selected because of its applicability to solving problems with both linear and nonlinear equations, as well as stationary and nonstationary parameters and variables, along with the relative simplicity of the mathematical and algorithmic implementation of computations. The calculations result in weight functions of the electrical model of the microarc-oxidation process, reflecting the relationship between the voltage and current in the galvanic cell (coating conductivity). The mean values of the weight functions (average conductivity) decrease during coating deposition, which confirms the adequacy of the proposed model and enables its use for implementing real-time procedures for monitoring coating properties. The scientific novelty of the work lies in the possibility of the real-time control of microarc oxidation through parametric identification of the electrical parameters of coatings using the matrix-operator method. [ABSTRACT FROM AUTHOR]

This article is dedicated to investigating the impact of different electrolyte compositions on the development of titanium coatings endowed with superior mechanical, tribological, and corrosion properties. An experimental analysis was conducted on three distinct electrolyte formulations, each contributing unique attributes to the coating's structural formation. Advanced analytical techniques, including scanning electron microscopy, hardness testing, wear resistance evaluation, and corrosion trials in harsh environments, were employed to gauge the mechanical, tribological, and anti-corrosive performance of the coatings. The utilization of scanning electron microscopy, X-ray structural analysis, and additional methodologies enabled an in-depth characterization of the microstructure and elucidated the relationship between the physico-mechanical properties and the electrolyte's chemical makeup. Among the electrolytes examined, the composition containing potassium hydroxide emerged as superior, fostering coatings with a distinctively porous structure that augment mechanical attributes. A considerable degree of porosity coupled with relatively small pore dimensions suggests the potential to engineer structures that exhibit optimal mechanical robustness. Furthermore, research findings related to this specific electrolyte composition revealed enhancements in the friction coefficient and wear resistance, indicating its promising prospects for tribological applications. The study also meticulously addressed the corrosion aspects, revealing that the microarc oxidation-derived coatings substantially improve corrosion resistance by offering more favorable potentials and currents than the bare titanium substrate. The efficacy of microarc oxidation as an avant-garde technique to advance the properties of titanium alloys underscores its prospective utility and practical relevance in contemporary industrial applications. [ABSTRACT FROM AUTHOR]

This work proposed a strategy of indirectly inducing uniform microarc discharge by controlling the content and distribution of β-Mg17Al12 phase in AZ91D Mg alloy. Two kinds of nano-particles (ZrO2 and TiO2) were designed to be added into the substrate of Mg alloy by friction stir processing (FSP). Then, Mg alloy sample designed with different precipitated morphology of β-Mg17Al12 phase was treated by microarc oxidation (MAO) in Na3PO4/Na2SiO3 electrolyte. The characteristics and performance of the MAO coating was analyzed using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), contact angle meter, and potentiodynamic polarization. It was found that the coarse α-Mg grains in extruded AZ91D Mg alloy were refined by FSP, and the β-Mg17Al12 phase with reticular structure was broken and dispersed. The nano-ZrO2 particles were pinned at the grain boundary by FSP, which refined the α-Mg grain and promoted the precipitation of β-Mg17Al12 phase in grains. It effectively inhibited the "cascade" phenomenon of microarcs, which induced the uniform distribution of discharge pores. The MAO coating on Zr-FSP sample had good wettability and corrosion resistance. However, TiO2 particles were hardly detected in the coating on Ti-FSP sample. [ABSTRACT FROM AUTHOR]

The repair and reconstruction of large bone defects after bone tumor resection is still a great clinical challenge. At present, orthopedic implant reconstruction is the mainstream treatment for repairing bone defects. However, according to clinical feedback, local tumor recurrence and nonunion of bone graft are common reasons leading to the failure of bone defect repair and reconstruction after bone tumor resection, which seriously threaten the physical and mental health of patients. On this basis, here the self-developed low modulus Ti-12Mo-10Zr alloy (TMZ) was chosen as substrate material. To improve its biological activity and osteointegration, calcium, oxygen, and phosphorus co-doped microporous coating was prepared on TMZ alloy by microarc oxidation (MAO). Then, black phosphorus (BP) nanosheets were incorporated onto MAO treated TMZ alloy to obtain multifunctional composites. The obtained BP-MAO-TMZ implant exhibited excellent photothermal effects and effective ablation of osteosarcoma cancer cells under the irradiation of 808 nm near infrared laser, while no photothermal or therapeutic effects were observed for TMZ alloy. Meanwhile, the structure/component bionic coating obtained after MAO treatment as well as the P-driven in situ biomineralization performance after incorporation of BP nanosheets endowed BP-MAO-TMZ implant with synergistic promoting effect on MC3T3-E1 osteoblasts' activity, proliferation and differentiation ability. This study is expected to provide effective clinical solutions for problems of difficult bone regeneration and tumor recurrence after tumor resection in patients with bone tumors and to solve a series of medical problems such as poor prognosis and poor postoperative quality of patients life with malignant bone tumors. [ABSTRACT FROM AUTHOR]

For the first time, a promising method for protecting the surface of metals and alloys from external high-temperature effects is proposed and substantiated experimentally by creating a functionally graded coating with a finishing ceramic layer and a precursor intermetallic layer. The technology of gas dynamic cold spraying of a mechanical mixture of powders based on aluminum valve metal with heat treatment is developed. [ABSTRACT FROM AUTHOR]

It is known that the methods of electrolytic oxidation, including traditional anodizing and microarc oxidation, implemented according to classical schemes in electrolytic baths with mechanical, pneumatic, and magnetic mixers, cannot provide high-quality homogeneous oxide coatings on the inner surfaces of products made from valve metal alloys. In this paper, the principal possibility of obtaining high-quality uniform coatings on the extended internal surfaces of products, including the surfaces of deep holes, when an electrolyte solution is passed through them, is revealed. It has been experimentally proved that, based on the proposed approach, it is possible to process products with deep holes, achieving a ratio of both minimum and maximum values of the thickness and the breakdown voltage of coatings on the internal and external surfaces in a range of 0.85–0.93. A possibility of forming coatings exclusively on the internal surfaces of products without changing the state of their external surfaces, moreover, without using expensive electrolytic baths—inside internal cavities of products themselves, is shown. A good correlation between the values of the thickness and of the breakdown voltage of coatings has been established. As a result, a possibility of indirectly determine the coatings thickness based on the results of their breakdown voltage measuring has been substantiated. [ABSTRACT FROM AUTHOR]

The influence of the parameters of thermal, electrochemical, and microarc oxidation on the laws of formation of oxide barrier coatings on a VT23 titanium alloy (Ti–Al–V–Mo–Cr–Fe system) is studied. The resistance of the formed coatings to the subsequent vacuum annealing at 800°C for 1 h is examined. The coating thickness is shown to increase with the oxidation temperature or voltage. The coatings produced by thermal and microarc oxidation are most resistant to heating in vacuum, but those produced by microarc oxidation contain pores. The anodic oxide coating is completely dissolved upon vacuum annealing. [ABSTRACT FROM AUTHOR]

A MA8 magnesium alloy substrate was pre-impregnated in aqueous solutions of cerium(III) nitrate and glycerol before microarc oxidation, which was used to form oxide ceramic coatings from a silicate–alkaline electrolyte containing fluoride ions. The corrosion-protection properties of these coatings on the pre-impregnated alloy surface were assessed using potentiodynamic polarization curves. Electrochemical parameters calculated from the potentiodynamic polarization curves showed that the presence of the oxide ceramic coating on the surface of MA8 magnesium alloy significantly reduces the corrosion current density and increases the polarization resistance. It was determined that the pre-impregnation of the MA8 magnesium alloy substrate in aqueous solutions of cerium(III) nitrate and glycerol affects the mechanism of the corrosion damage. [ABSTRACT FROM AUTHOR]

Questions of raising the efficiency and controllability of the process of depositing protective microarc oxide coatings with specified properties on products made of light metals and alloys (aluminum, magnesium, titanium) are examined. An intelligent information-measurement system is developed for measuring the parameters of microarc oxide coatings which contains unique hardware, program, and information support. For the hardware support of the system a technological current source is created that specifies the technical regimes, strength and shape of the current (a sinusoidal or pulsed signal is possible) which to a great extent determines the parameters of the formed coatings. Original circuit solutions in the area of pulsed power electronics, along with modern electronic components, are used for developing the source. The technological current source has a high efficiency and provides a complete range of regulation of the parameters of the energy effect on a test sample where a coating is being formed. The developed intelligent informationmeasurement system is intended for high current measurements of the process parameters and properties of the resulting coatings; it can be used for automatic monitoring of microarc oxidation, as well as for scientific studies. Intelligent application and the knowledge bank of the system ensure intelligent choice of the optimum technological parameters of microarc processing, along with automatically controlled synthesis of microarc oxide coatings with specified properties. [ABSTRACT FROM AUTHOR]

Complex salt solution systems are commonly used as electrolytes for microarc oxidation (MAO). To investigate the MAO phenomenon in simple electrolytes and evaluate the efficacy of MAO coatings, an Na3PO4 monosalt solution was used as the MAO electrolyte. In this study, the effects of the voltage and Na3PO4 concentration on the spark discharge phenomenon, thickness, roughness, and corrosion resistance of the coatings were investigated. The results showed that MAO coatings were effectively synthesised at high concentrations and voltages. Furthermore, the addition of KOH to the Na3PO4 monosalt solution resulted in discernible spark discharge and improved the corrosion resistance of the coatings. Thus, an MAO coating can be efficiently prepared using Na3PO4 solution as the electrolyte. In addition, the addition of KOH to the Na3PO4 monosalt solution reduced the voltage required for coating formation and enhanced the corrosion resistance of the coating. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents a hypothesis, phenomenological and mathematical models of the exhaust gas neutralization process of an internal combustion engine inside the combustion chamber. The neutralization of exhaust gasses is estimated from surface catalytic properties of the coating, formed on the surface of the combustion chamber parts by microarc oxidation. Phenomenological and mathematical models of the exhaust gases neutralization process in the combustion chamber were developed. Phenomenological model of neutralization process is based on particle diffusion into the surface layer of the coating. Mathematical model is based on Fick's first law and takes into consideration great amount of factors, which affect the process of neutralization: geometrical dimensions and operating characteristics of the engine; properties of coating and exhaust gasses composition. Verification of developed mathematical model was shown in this work. During verification, experimental data, acquired using motor tests of two-stroke 2-cylinder engine RMZ-551 was applied. Calculations were done for the most indicative operating mode of the engine, in which the highest effect of neutralization can be observed. A comparative analysis of the calculated and experimental data was carried out using the concentrations of the CO and NOx components. Calculated values, acquired with the developed mathematical model, differ from experimental values of concentration decrease of previously said exhaust gasses components by 23.3 and 30.4%, respectively. It shows that presented mathematical model could be used for obtaining computational high convergence results. [ABSTRACT FROM AUTHOR]

This article provides the results of corrosion resistance tests of nanostructured oxide-ceramic coatings produced by microarc oxidation on aluminum alloys in a boric acid electrolyte. The coatings were formed on a microarc oxidization plant used in anode-cathode mode. Accelerated corrosion tests were conducted by alternating the immersion of the specimens in sodium chloride solution with their drying in the air. At the microarc oxidation of aluminum alloys in a boric acid electrolyte, the corrosion levels directly depend on microarc oxidation mode and chemical composition of oxidated alloys. At a density of 10–20 A/dm2, continuous corrosion is observed, whereas at a current density of 20–30 A/dm2 staining is observed, which is caused by the fact that corrosive medium penetrates through the pores and produces poultice corrosion. The oxide ceramic coatings on D16 alloys exhibit a weaker resistance to corrosion than on AMg2 and AD1 alloys. It has been established that the corrosion values of aluminum alloys with nanostructured oxide-ceramic coatings are severalfold as low as in uncoated alloys. [ABSTRACT FROM AUTHOR]

The effect of the duration of the microarc-oxidation process on the thickness, roughness, and optical characteristics (solar absorbance αs and emissivity ε) of white and black thermal-control coatings formed on an aluminum alloy AMg6 is studied experimentally. It is found that αs decreases with an increase in the thickness of the coatings with increasing microarc-oxidation-treatment duration. For the white coatings, a decrease in their roughness is accompanied by an increase in ε, and vice versa. For the black coatings, the main role is played by the emissivity factor of the coating, which is determined by the content of vanadium oxide in it. A comparative analysis of the optical characteristics of thermal-control coatings obtained using the microarc-oxidation process on various aluminum alloys show that it is better to form white coatings of the solar-reflector class on aluminum alloy AMg3 and black coatings of the true-absorber class on an aluminum alloy AMg6 with a microarc-oxidation (MAO) treatment duration of 25 min. The obtained experimental data can serve as a framework for the development of a basic technology for the formation of thermal-control coatings on products made of aluminum alloys. [ABSTRACT FROM AUTHOR]

Microarc Oxidation (MAO) technology can prepare a ceramic-like oxide coating. It is an effective technique to increase the wear and corrosion resistance of magnesium alloys. The MAO coating has many defects such as holes and cracks. As well, the coating on magnesium alloys typically consists mainly of MgO, which absorbs water or dissolves in a humid or acidic environment. Therefore, the MAO coatings are not adequate for the long-term protection of magnesium alloys. MAO coatings that are composed of ZrO2, or which have ZrO2 with a compact microstructure, can improve the protection of magnesium alloys. This paper critically summarizes the progress of MAO coatings containing ZrO2 on magnesium alloys from four aspects: electrolyte compositions, electrical parameters, the two-step MAO process, and post-treatment of MAO coating. The future research directions for MAO coatings containing ZrO2 on magnesium alloys are discussed. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the aim of further enhancing the bioactive performance of Ti–6Al–4V, ultrasonic‐assisted microarc oxidation (MAO) and hydrothermal (HT) treatments are combined to produce denser, more uniform hydroxyapatite (HA) crystals on the MAO coating herein. More Ca elements can be deposited on the coating and more TiO2 can be generated to form a thicker coating via ultrasonic assistance. Meanwhile, the MAO coating with ultrasonic assistance avoids the appearance of heterogeneous areas and homogenizes the distribution of elements. Those positive effects of ultrasonic‐assisted MAO coating provide favorable conditions for the subsequent HT treatment to form dense and uniform HA crystals. In vitro experiment shows that the ultrasonic‐assisted MAO coating has a higher number of MG63 cells compared with other samples. Moreover, the formation of HA crystals improves the biological activity of all samples. In the ultrasonic‐assisted sample after HT treatment, denser and more uniform HA crystals on the coating surface result in the higher alkaline phosphatase activity of the sample. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Microarc oxidation (MAO) is an effective surface treatment method for Ti alloys to allow their application in extreme environments. Here, binary electrolytes consisting of different amounts of sodium phosphate and sodium silicate were designed for MAO. The surface morphology, composition, and properties of MAO coatings on Ti−6Al−4V alloy treated in 0.10 mol/L electrolyte were investigated to reveal the effect of PO43− and SiO32− on the growth kinetics of the MAO coatings, using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and potentiodynamic polarization. The results showed that PO43− is beneficial for generating microarcs and forming pores within the coating, resulting in a thick but porous coating. SiO32− facilitates the blocking of pores in the outer deposition layer and impedes the generation of microarcs, resulting in a thin dense coating. The thickness, density, phases content, and polarization resistance of the MAO coatings are primarily affected by the intensity of microarcs for low SiO32− contents, and by the number of microarcs when the SiO32− content is sufficiently high. The thickness of MAO coatings obtained in P/Si electrolytes shows a piecewise linear increase with increasing process time during the three stages of microarc discharge. SiO32− is beneficial to the density increase of the coating formed in the previous stage of microarcs discharge, but slows down the growth of the coating formed in the next stage. [ABSTRACT FROM AUTHOR]

To improve the corrosion resistance of 7075 aluminum alloy microarc oxidation (MAO) coating, graphene of 3 g/L was adsorbed and deposited in the coating. Then, the microarc oxidation–sol–gel (MAO-SG) composite coating was obtained by sealing the micropores of the coating with TiO2 sol–gel. Electrochemical tests of 7075 aluminum alloy matrix, undoped sample, doped graphene sample and sealed sample were carried out in 3.5wt.% NaCl solution. The results show that compared with the blank sample, the self-corrosion potential of the sealed sample is increased by 98.1%, and the self-corrosion current density is reduced by 4 orders of magnitude. After immersion corrosion for 720 h, the corrosion rate of MAO-SG composite coating is 3.4 × 10–5 mm/a, and its corrosion resistance is still better than that of single MAO coating. This is due to the strong conductivity of graphene and the blocking effect of TiO2 sol–gel. [ABSTRACT FROM AUTHOR]

The effects of high- and low-frequency coupled square wave pulses and concentration of TiC on TiC/Al2O3 coatings were determined through microarc oxidation on 6063 aluminum alloy. Scanning electron microscopy results showed that the "stack" of micropores and the thickness increased with the increase in TiC concentration and high-frequency pulse amplitude. X-ray diffraction and x-ray photoelectron spectroscopy results showed that the composite coatings primarily consisted of γ-Al2O3, α-Al2O3, TiC, and Al2SiO5. The TiC content increased, the surface hardness of the coatings improved from 781.5 to 1321.4 Hv, and the corrosion current density decreased from 1.497 × 10−6 to 8.979 × 10−10 A cm−2. The friction coefficient decreased from 0.52 to 0.41 at the TiC content of 3 g/L and high-frequency pulse amplitude of 30 V. The TiC content and high-frequency pulse amplitude improved the corrosion and friction performance of the TiC/Al2O3 coatings. [ABSTRACT FROM AUTHOR]

Si3N4/TaC composite MAO coatings were fabricated by microarc oxidation (MAO) on a Ti–6Al–4V (TC4) alloy in a phosphate-based electrolyte containing Si3N4/TaC mixed particles. The influence of the amount of Si3N4/TaC particles on the microstructure, composition, tribological behavior, and corrosion properties of the MAO coatings has been investigated. Morphological research of the MAO coatings was carried out using scanning electron microscopy (SEM), with the surface porosity analyzed by ImageJ software. X-ray diffraction (XRD) was used for the detection of the phase characteristic of the MAO coatings, and an abrasive wear test and electrochemical measurements were conducted in the artificial seawater solution by the ball-on-disc friction tester and the electrochemical workstation, respectively. The results showed that Si3N4/TaC particles could be successfully incorporated into the composite coatings, and the addition of Si3N4/TaC particles greatly reduced the porosity of the coatings, thus improving both tribological and corrosion properties of the composite MAO coatings. The composite MAO coating with the addition of 1 g/L Si3N4 + 0.5 g/L TaC particles showed the best tribological property and the optimum corrosion properties. [ABSTRACT FROM AUTHOR]

Corrosion is an inevitable and thorny issue in various fields, resulting in materials degradation, environmental pollution, economic loss, and even emergency safety accidents. Owing to the special surface functions, superhydrophobic coatings are regarded as a promising strategy towards corrosion inhibition. However, the large‐scale and real‐world applications of superhydrophobic coatings are restricted by the mechanical and chemical weaknesses. Herein, a fluorine‐free dual‐layer microarc oxidation/superhydrophobic coating with mechanochemical stabilization is fabricated for corrosion protection. The dual‐layer coating maintains superhydrophobicity under ultraviolet irradiation (15 d), different pH values (1–14), different temperatures (0–100 °C) and abrasion test (180 cycles). Its impedance modulus at the lowest frequency is increased by more than six orders of magnitude than that of the pristine substrate, and the corrosion inhibition efficiency value is calculated as 99.999%. The enhancement of surface multifunctions is attributed to the synergistic effects of microarc oxidation layer and superhydrophobic layer. The as‐prepared robust dual‐layer coating with excellent properties is expected to have potential applications in material protection fields. [ABSTRACT FROM AUTHOR]

In this study, the 10B21 steel was treated by micro-arc oxidation (MAO) in the electrolyte consisting of aluminate and phosphate to enhance its corrosion resistance. The effect of negative voltage on corrosion resistance of the MAO coating obtained has mainly been analyzed through their phase composition, microstructure, interfacial bonding strength, salt spray and electrochemical testing. The result indicates that with negative voltages applied to the MAO coating, Fe-Al transition layers arise between coating layer and matrix. Furthermore, different negative voltages bring forward different α-Al2O3 contents contained in the MAO coatings and when it reaches −100 V, the amount of α-Al2O3 appears as the largest. The surface porosity of the coating was also significantly decreased. In addition, the corrosion current density of the coating is only 3.64 μA·cm−2, which is two orders of magnitude lower than that of the substrate. After 72 h of salt spray corrosion, it is found that the coating substrate is less corroded when the negative voltage of 100 V is applied. Therefore, −100 V has been proven as the optimum performance for improving the corrosion resistance of 10B21 steel. [ABSTRACT FROM AUTHOR]

Heat transfer and critical heat flux on flat rectangular (16 × 24 mm) heat-releasing surfaces (HS) made of aluminum alloy D16 and modified by microarc oxidation (MAO) were investigated. Two types of coatings made using different electrolytes were studied: KOH and phosphates. Coatings had good adhesion to the HS and high dielectric strength. The thickness of coatings was 20 and 7 µm, respectively. The studies were carried out using freon R21 under conditions of natural convection with horizontal orientation of the HS. For comparison, measurements were carried out on identical test sections without a modifying coating: the first section was polished; the second one was ground with a roughness of 20 µm. It was shown that the heat transfer intensity on the modified HS was not lower than that on the ground HS with a roughness of 20 µm, and it was almost twice as high as that on the polished HS. The values of the critical heat flux on the studied surfaces were almost the same. The use of these types of coatings provides electrical insulation of the heat-releasing element without compromising the efficiency of heat removal. [ABSTRACT FROM AUTHOR]

Background: Microarc oxidation (MAO) on the surface of medical pure titanium can improve its histocompatibility, and loading drugs on the surface can resist excessive intimal hyperplasia. Methods: In this study, salidroside (SAL) was loaded on the surface of porous titanium (Ti) with polydopamine (PDA) carrier. The effects of SAL on the osteogenesis and angiogenesis of Ti implants were studied by phalloidin staining, alizarin red staining, ALP staining, wound-healing assay, cell transwell assay, matrigel tube formation, and osteogenic and angiogenic genes and proteins expression detected by PCR and western blot in vitro. The bone defect model experiments in rats was established in vivo including X-ray, micro CT, hematoxylin and eosin staining (HE), immunohistochemistry (IHC), Goldner's trichrome analysis, Safranin O-fast green staining and determination of contents of TNF-α and IL-6 in serum. Results: EDS and EDS mapping showed that SAL could be loaded on the surface of the MAO coating by PDA. A drug release experiment showed that SAL loaded on the Ti coating could release slowly and stably without sudden release risk. In vitro cell experiments showed that the SAL coating could promote the proliferation, morphology, calcification and alkaline phosphate activity of MC3T3-E1 cells. At the same time, it promoted the migration and tube formation of HUVEC cells. The SAL coating promoted osteogenesis and angiogenesis by promoting the expression of genes and proteins related to. In vivo experiments, HE and IHC showed that SAL significantly promoted the expression of COL-1 and CD31. Goldner's trichrome and Safranin O-fast green staining showed that SAL coating could increase the new bone tissue around the implantation site. The SAL coating had anti-inflammatory activity by reducing the levels of TNF-α and IL-6 in vivo. Conclusion: Therefore, SAL could improve osteogenesis and angiogenesis in conjunction with the Ti-PDA coating. [ABSTRACT FROM AUTHOR]

To refine microarc oxidation (MAO) coating surface micropores, and enhance the coating's toughness and oxidation resistance. In the process of MAO, negatively charged CeO2 particles are adsorbed and deposited into the coating under the action of electrophoresis, and a 6 g/L CeO2 doped MAO coating is prepared. Then, the Al2O3-SiO2 composite sol-gel seal coating was used to obtain the microarc oxidation-sol-gel composite coating (MAO-SG). The TC4 substrate, undoped MAO coating, CeO2 doped MAO coating, and MAO-SG composite coating were subjected to high-temperature oxidation at 650, 750, and 850°C, respectively. The results show that the composite coating exhibits excellent high-temperature oxidation resistance at three temperatures. Compared with the undoped MAO coating, the maximum oxidation weight gain per unit area of the MAO-SG coating was reduced by 13.44%, 23.87%, and 38.16%, and the average oxidation rate was reduced by 17.15%, 50.98%, and 69.37%, respectively. The sol-gel layer on the surface of the composite coating will decompose α-Al2O3 at high temperatures, and form a dense protective layer on the surface of the MAO coating and protect the MAO coating, which greatly improves the high-temperature oxidation resistance of the TC4 titanium alloy. [ABSTRACT FROM AUTHOR]

The the main results of development of thermodynamic physicochemical simulation of microarc oxidation on an aluminum alloy in an atypical aqueous borate electrolyte of predefined composition under conditions of varying temperature are discussed. In the scope of this study, the appropriate methods of solution and thermodynamic databases have been developed for efficient implementation of the simulation system. The roles of each component of the aqueous borate electrolyte as well as of aluminum substrate have been substantiated, and the influence of state variables (composition and temperature) on physicochemical transformations has been determined for the conditions of microarc oxidation in borate solutions. The results define the basis for application of the obtained regularities and subsequent optimization of microarc oxidation aimed at production of coatings with preset operation properties. [ABSTRACT FROM AUTHOR]

A method for modification of calcium-phosphate coatings, formed by microarc oxidation, with Fe–Cu nanocomposite bicomponent particles is proposed. The effect of modification of calcium-phosphate coatings, formed on titanium, with Fe–Cu nanoparticles on their morphological, structural and mechanical characteristics is evaluated. It is found out that the highest adhesion strength (33 MPa) is exhibited by the coatings with a thickness of 42–50 μm, which were formed at the microarc oxidation voltage of 200 V in the electrolyte containing Fe–Cu nanoparticles. These coatings are characterized by a roughness (Ra) of 3.3 μm, a surface porosity of 21% and a higher content of calcium compared to that in the initial unmodified coating. [ABSTRACT FROM AUTHOR]

The wear resistance of sheet magnesium alloy AZ31 (Mg – 2.90% Al – 0.98% Zn – 0.13% Mn) with microarc oxidation coatings after shot peening is determined. The microstructure of the alloy is studied by scanning electron microscopy. The effect of the shot peening on formation of cracks and pores in the alloy after microarc oxidation and on the roughness of the surface is determined in order to predict the wear resistance of the alloy under dry friction. [ABSTRACT FROM AUTHOR]

The article considers the technological aspects of temperature estimation in an aluminum specimen with the possible formation of an aluminum-containing coating on its surface using the combined technology of cold gas dynamic deposition and microarc oxidation. The experimental results for the temperature flow distribution over the thickness of the metal surface under the cold gas dynamic deposition are presented. The temperature of the heat flow during spraying was varied from 200 to 600°C. It was found that the operating temperature of the aluminum substrate with a thickness of 8 mm at the standard thermal deposition modes is not more than 120°C, which is one of the advantages of the used technology over the known methods of plasma and magnetron sputtering. The temperature effect of the microarc oxidation on the surface of a specimen depending on various technological modes is estimated. It was found that the surface temperature of the specimen oxidized in an alkaline electrolyte with liquid glass additives at current densities of 20–30 A/dm2 is not more than 90°C, which shows the absence of thermal transformations. [ABSTRACT FROM AUTHOR]

The results of studying the morphology, porous structure, and corrosion and diffusion properties of boehmite-containing calcium phosphate coatings formed by microarc oxidation on titanium substrates are presented. Boehmite nanoparticles obtained as a result of the AlN hydrolysis were deposited on the surface of microarc coatings with a developed relief. With an increase in the duration of the preliminary ultrasonic treatment (UST) of the AlN suspension in the interval of 20–60 min, the size of agglomerates of boehmite nanoparticles on the coating surface is decreased from 200 to 40 μm. The surface porosity of the modified coatings and the area occupied by boehmite particles are decreased from 36 to 33% and from 27 to 10%, respectively. Agglomerates with boehmite nanoparticles after 60 min of UST of an AlN powder suspension are distributed in the coating more uniformly than after 20 min of treatment. When the duration of UST of the initial suspensions is increased, the effective diffusion coefficients of the model biological fluid in porous coatings is decreased from 7.98 × 10–11 to 7.25 × 10–11 m2/s. Modification of calcium phosphate coatings with boehmite nanoparticles by varying the duration of UST of AlN powder increases the corrosion resistance of the surface layers. [ABSTRACT FROM AUTHOR]

Porous magnesium oxide (MgO) ceramic layers were prepared on AZ31 magnesium alloy via microarc oxidation (MAO) and sustained hydrothermal treatment at 90°C for 18 h in alkaline zinc nitrate solution with varying Al3+ concentrations. Increasing the Al3+ concentration advanced the formation of layered double hydroxide (LDH) films on the MgO ceramic layers, enabling the sealing of micropoles and cracks via in situ growing. Electrochemical and immersion test results indicated that the MAO/hydrothermal treatment‐prepared LDH/MgO composite coatings achieved increased corrosion resistance than single MAO ceramic layers, due to the sealing effect and ion‐exchange capacity of LDHs. Furthermore, as Al3+ concentration in hydrothermal solution increased, the anticorrosion properties of the composite coatings were enhanced. Concludingly, LDH/MgO composite coatings could provide augmented long‐term anticorrosion protection for magnesium alloys compared with single MAO ceramic layers. [ABSTRACT FROM AUTHOR]

A thickness distribution model of a coating formed under microarc oxidation of aluminum and its alloys is considered for two extreme cases: a point cathode and a cathode parallel to the sample surface. In the case of the point cathode, the change in the thickness of the formed aluminum coatings was determined. It was experimentally established that the best results for the uniform distribution of the coating thickness in the process of microarc oxidation are provided by the condition of plane-parallel installation of electrodes (cathodes) relative to the plane of the oxidized sample. The main technological factors determining the operational properties of coatings formed in this way are considered. [ABSTRACT FROM AUTHOR]

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The characteristics of the oxide layer deposited by microarc oxidation (MAO) on Al – Si alloys in a silicate-alkaline electrolyte are studied. The thermal conductivity of the layer at 50 – 120°C is determined using a special facility by the method of stationary heat flow. The thickness, the porosity, the elemental composition, the content of the amorphous phase, and the size of the crystallites in the oxide layer are determined. The results obtained are analyzed and the conditions for the lowest thermal conductivity of the oxide layer are determined. [ABSTRACT FROM AUTHOR]

The development of composite coatings essential to improve the wear and corrosion resistances of the materials employed in numerous applications, such as automobile, chemical, medicine, construction, aerospace, and biomedical industries. In this study, we presented a double-layer coating technique, which consisted of a thermal-sprayed titanium (Ti) layer and a micro-arc oxidation (MAO) film on AISI 1020 steel. The effect of the composite coatings (Ti/MAO) on wear and corrosion resistance was investigated. To obtain a coating thickness from 250 mm to 450 mm, the prepared specimens were coated with Ti (99.9% pure) by arc spraying. Then, the Ti/MAO films were deposited on Ti coatings. The current density of MAO was fixed at 35 A/dm², the voltages were 250, 300, 350, 400, and 450 V, and the duration of the MAO process was 10 min, Measurements of film thickness, microstructure, microhardness, X-ray diffractometry analysis, and scanning electron microscopic observation were performed for determining the characteristics of the composite coatings (Ti/MAO). Potentiodynamic polarization curves were used to compare the corrosion resistance of these composite coatings. A ball-on-disc wear test, using an oscillation friction wear tester, was carried out at room temperature according to the ASTM G99 standard to determine the wear resistance. Among all the specimens, Ti/MAO (400 V) had the greatest hardness, lowest friction coefficient, least weight loss, and longest sliding distance. The sliding distance of Ti/MAO (400 V) was about 1.7 times higher than those of Ti. The open-circuit potential of Ti/MAO (400 V) was about 1.7 times better than those of Ti. The corrosion currents of Ti/MAO (250 V) and Ti/MAO (400 V) were decreased by MAO about 95% and 92%, respectively. Although the corrosion current of Ti/MAO (400 V) was higher than that of Ti/MAO (250 V), Ti/MAO (400 V) had better effects in other tests. According to the results, Ti/MAO (400 V) presented the best performance among all the specimens and provided improved protection to both Ti and substrate. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Processing of Materials / Elektronnaya Obrabotka Materialov is the property of Institute of Applied Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The structural and phase transformation of microarc oxidation (MAO) coatings on 6061 aluminum alloy at 300∘C/3 MPa steam were evaluated. After 10 days steam corrosion, the weight loss of coated alloys with 15 μ m and 75 μ m thickness was only about 1/10 and 1/50 of weight gain of bare alloy, respectively. The γ -Al2O3 and α -Al2O3 phases in the MAO coatings were stable at 300∘C/3 MPa steam, but many fine needle-like or brick-like boehmite crystalline particles also appeared on coating surface. The boehmite had a large influence on the permittivity of coatings at low frequency. The MAO treatment on 6061 aluminum alloy improved its corrosion resistance at high-temperature and high-pressure steam. [ABSTRACT FROM AUTHOR]

Dental implants are the most innovative and superior treatment modality for tooth replacement. However, titanium implants still suffer from insufficient antibacterial capability and peri-implant diseases remain one of the most common and intractable complications. To prevent peri-implant diseases, a composite coating containing a new antibacterial agent, (Z-)-4-bromo-5-(bromomethylene)-2(5H)-furanone (BBF) was fabricated on titanium. This study was designed to investigate the antibacterial activity of the composite coating against two common peri-implant pathogens (Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans). The morphology of the composite coating showed that BBF-loaded poly(L-lactic acid) nanospheres were well-distributed in the pores of the microarc oxidation coating, and cross-linked with each other and the wall pores by gelatin. A release study indicated that the antibacterial coating could sustain the release of BBF for 60 d, with a slight initial burst release occurring during the first 4 h. The antibacterial rate of the composite coating for adhering bacteria was the highest (over 97%) after 1 d and over 90% throughout a 30-day incubation period. The total fluorescence intensity of the composite coating was the lowest, and the vast majority of the fluorescence was red (dead bacteria). Moreover, real-time polymerase chain reaction analysis confirmed that the relative gene expression of the adherent bacteria on the composite coating was down-regulated. It was therefore concluded that the composite coating fabricated on titanium, which showed excellent and relatively long-term antibacterial activity against Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans, is a potential and promising strategy to be applied on dental implants for the prevention of peri-implant diseases. [ABSTRACT FROM AUTHOR]

The development of composite coatings essential to improve the wear and corrosion resistances of the materials employed in numerous applications, such as automobile, chemical, medicine, construction, aerospace, and biomedical industries. In this study, we presented a double-layer coating technique, which consisted of a thermal-sprayed titanium (Ti) layer and a micro-arc oxidation (MAO) film on AISI 1020 steel. The effect of the composite coatings (Ti/MAO) on wear and corrosion resistance was investigated. To obtain a coating thickness from 250 mm to 450 µm, the prepared specimens were coated with Ti (99.9% pure) by arc spraying. Then, the Ti/MAO films were deposited on Ti coatings. The current density of MAO was fixed at 35 A/dm², the voltages were 250, 300, 350, 400, and 450 V, and the duration of the MAO process was 10 min, Measurements of film thickness, microstructure, microhardness, X-ray diffractometry analysis, and scanning electron microscopic observation were performed for determining the characteristics of the composite coatings (Ti/MAO). Potentiodynamic polarization curves were used to compare the corrosion resistance of these composite coatings. A ball-on-disc wear test, using an oscillation friction wear tester, was carried out at room temperature according to the ASTM G99 standard to determine the wear resistance. Among all the specimens, Ti/MAO (400 V) had the greatest hardness, lowest friction coefficient, least weight loss, and longest sliding distance. The sliding distance of Ti/MAO (400 V) was about 1.7 times higher than those of Ti. The open-circuit potential of Ti/MAO (400 V) was about 1.7 times better than those of Ti. The corrosion currents of Ti/MAO (250 V) and Ti/MAO (400 V) were decreased by MAO about 95% and 92%, respectively. Although the corrosion current of Ti/MAO (400 V) was higher than that of Ti/MAO (250 V), Ti/MAO (400 V) had better effects in other tests. According to the results, Ti/MAO (400 V) presented the best performance among all the specimens and provided improved protection to both Ti and substrate. [ABSTRACT FROM AUTHOR]

Purpose: To compare bone augmentation on pure titanium-machined surfaces and surfaces that have been modified by microarc oxidation (MAO) using titanium caps. Materials and Methods: Twenty caps were manufactured from rods of commercially pure titanium. The control group (CG) consisted of 10 titanium caps with machined inner walls. The test group (TG) consisted of 10 titanium caps that were modified by MAO in an electrolyte solution containing calcium phosphate ions. The two types of titanium caps were fixed on the calvaria of 10 New Zealand rabbits. Each rabbit received two different caps. Although each cap was unfilled, the marrow and blood from the wound of the rabbit skulls could penetrate into the caps. After 4 weeks, the rabbits were sacrificed, and the skulls were removed for observation. The zenith of new bone was measured directly after the caps were removed from the skulls; subsequently, the bone volume was calculated by microcomputed tomography. Results: Little bone augmentation could be observed in the CG caps, and the new bone height of the CG group was inconspicuous. In contrast, the new bone extended along the inner walls of the TG caps. The mean height of new bone of the TG group was 2.3 ± 0.28 mm. The mean volume of new bone in the TG group was 18.63 ± 3.80 mm3. Conclusions: New bone formation in a titanium cap surface modified by MAO was greater than that of a nonmodified cap. A titanium cap allowed new bone formation on the MAO surface to be observed and is a promising device for bone augmentation. Additionally, this finding suggests that observation through a titanium cap is a feasible method for biomaterial testing in hard tissue. [ABSTRACT FROM AUTHOR]

This work presents the results of studies of structural and physicomechanical characteristics of oxide-ceramic coatings obtained on aluminum by microarc oxidation in an alkaline silicate electrolyte with various contents of silicate ions using alternating and direct currents. [ABSTRACT FROM AUTHOR]

Background: The biofunctionalization of titanium implants for high osteogenic ability is a promising approach for the development of advanced implants to promote osseointegration, especially in compromised bone conditions. In this study, polyelectrolyte multilayers (PEMs) were fabricated using the layer-by-layer approach with a chitosan-miRNA (CS-miRNA) complex and sodium hyaluronate (HA) as the positively and negatively charged polyelectrolytes on microarc-oxidized (MAO) Ti surfaces via silane-glutaraldehyde coupling. Methods: Dynamic contact angle and scanning electron microscopy measurements were conducted to monitor the layer accumulation. RiboGreen was used to quantify the miRNA loading and release profile in phosphate-buffered saline. The in vitro transfection efficiency and the cytotoxicity were investigated after seeding mesenchymal stem cells (MSCs) on the CS-antimiR-138/HA PEM-functionalized microporous Ti surface. The in vitro osteogenic differentiation of the MSCs and the in vivo osseointegration were also evaluated. Results: The surface wettability alternately changed during the formation of PEMs. The CS-miRNA nanoparticles were distributed evenly across the MAO surface. The miRNA loading increased with increasing bilayer number. More importantly, a sustained miRNA release was obtained over a timeframe of approximately 2 weeks. In vitro transfection revealed that the CS-antimiR-138 nanoparticles were taken up efficiently by the cells and caused significant knockdown of miR-138 without showing significant cytotoxicity. The CS-antimiR-138/HA PEM surface enhanced the osteogenic differentiation of MSCs in terms of enhanced alkaline phosphatase, collagen production and extracellular matrix mineralization. Substantially enhanced in vivo osseointegration was observed in the rat model. Conclusions: The findings demonstrated that the novel CS-antimiR-138/HA PEM-functionalized microporous Ti implant exhibited sustained release of CS-antimiR-138, and notably enhanced the in vitro osteogenic differentiation of MSCs and in vivo osseointegration. This novel miRNA-functionalized Ti implant may be used in the clinical setting to allow for more effective and robust osseointegration. [ABSTRACT FROM AUTHOR]

Three types of surface treatments were performed on AZ80 magnesium (Mg) alloy by laser shock peening (LSP), microarc oxidation (MAO), and laser shock peening followed by microarc oxidation (LSP/MAO). The stress corrosion resistance of treated and untreated specimens was carried out using slow strain rate tensile testing at a strain rate of 5 × 10−7/s in simulated body fluid. The influence of microstructure on the stress corrosion behavior was analyzed by x-ray diffraction, transmission electron microscopy, scanning electron microscopy, and electrochemical measurement. The results showed that the LSP/MAO specimen has a higher stress corrosion resistance compared to the AZ80 Mg alloy substrate, the LSP-treated specimen, and the MAO-treated specimen. The factors improving the stress corrosion resistance of the LSP/MAO specimen are its nanocrystalline material, compressive residual stress, and favorable (0002) basal texture of its reconstructed layer. [ABSTRACT FROM AUTHOR]

The effect of electrolysis conditions with different electrolyte compositions on the growth kinetics, phase-structural state, and hardness of coatings obtained by microarc oxidation (MAO) on the D16 aluminum alloy (base - aluminum, main impurity Cu) was studied. An analysis of the results obtained showed that the choice of the type of electrolyte and the conditions for the MAO process makes it possible to vary the growth kinetics and phase-structural state of the coating on the D16 aluminum alloy within a wide range. For all types of electrolytes, with an increase in the content of KOH, Na2SiO3, or KOH+Na2SiO3, the growth rate of MAO coatings increases. It was found that in MAO coatings obtained in an alkaline (KOH) electrolyte, a two-phase (γ-Al2O3 and α-Al2O3 phases) crystalline state is formed. An increase in the KOH concentration leads to an increase in the relative content of the α-Al2O3 phase (corundum). During the formation in a silicate electrolyte, the phase composition of MAO coatings with an increase in the content of liquid glass (Na2SiO3) changes from a mixture of the γ-Al2O3 phase and mullite (3Al2O3∙2SiO2) to an X-ray amorphous phase. The use of a complex electrolyte leads to a two-phase state of the coating with a large (compared to an alkaline electrolyte) shift of the γ-Al2O3→α-Al2O3 transformation towards the formation of the α-Al2O3 phase. It was determined that the value of hardness correlates with the content of the α-Al2O3 phase in the MAO coating, reaching the maximum value of 1620 kg/mm2 at the highest content (about 80 vol. %) of the α-Al2O3 phase. Two types of dependences of the coating thickness on the amount of electricity passed were revealed. For the amount of passed electricity 10-50 A-h/dm2, the thickness dependence is determined as 4.2 μm/(A-h/dm2), which suggests the basic mechanism of electrochemical oxidation during the formation of a coating. For the amount of electricity transmitted 50-120 A-hour/ dm2, the thickness dependence is determined by a much smaller value of 1.1 μm/(A-hour/dm2). This suggests a transition to a different mechanism of coating formation - the formation of a coating with the participation of electrolysis components [ABSTRACT FROM AUTHOR]

The influence of electrolysis conditions at different electrolyte compositions on the phase formation and properties of coatings obtained by microarc oxidation (MAO) on an aluminum alloy AMg6 was studied. For electrolysis, three types of electrolytes were used: alkaline electrolyte ((KOH) solution in distilled water), silicate electrolyte (with different percentages of Na2SiO3 component) and complex alkaline silicate electrolyte with liquid glass (1÷12 g/l Na2SiO3) and potassium hydroxide (1÷6 g/l KOH). An analysis of the results showed that the choice of electrolyte type and conditions of the microarc oxidation process allows a wide variation in the phase-structural state, thickness and properties of the AMg6 aluminum alloy. The criterion for the expected phase-structural state of the coatings as a result of microarc oxidation is the completeness of the γ–Al2O3→α–Al2O3 transformation process during coating formation. The use of an alkaline electrolyte does not allow achieving a high hardness of the coating due to the formation of the γ -Al2O3 phase and the absence of thermodynamic conditions for the γ–Al2O3→α–Al2O3 transition. When using a silicate electrolyte, it is possible to significantly increase the growth rate of the coating, but at the same time, the presence of a large specific Si concentration stimulates the formation of mullite and an amorphous-like phase. The use of a combined alkaline silicate electrolyte (with different percentages of KOH+Na2SiO3) with a low content (6 g/l) of Na2SiO3 in solution stimulates the formation of mullite. This is manifested to the greatest extent with the lowest content (1 g/l) of the KOH component. At a higher content (2 g/l) of the KOH component, the processes characteristic of an alkaline electrolyte become dominant. This leads to an incomplete transformation reaction and the formation of only the γ-Al2O3 phase. The achievement of the thermodynamic conditions of the γ–Al2O3→α–Al2O3 conversion became possible with an increase in the specific Na2SiO3 content in the electrolyte solution to 12 g/l. In this case, MAO coatings were formed on the AMg6 alloy with the highest hardness of 1500 kg/mm2 and high electric strength of 12 V/μm. [ABSTRACT FROM AUTHOR]

In the present study, corrosion‐protective microarc oxidation (MAO) coatings were prepared on AZ31B, AZ80, and ZK60 cast magnesium alloy substrates in an alkaline silicate electrolyte. The corrosion performances of the uncoated and MAO‐coated alloys were investigated using electrochemical and salt spray chamber corrosion tests. The microstructure characterization and experimental results show that among the three alloys studied, the ZK60 Mg alloy exhibited the best and AZ31B the least corrosion resistance under the salt spray conditions. The MAO coating provided robust corrosion protection of the Mg substrates and resulted in a significant decrease in the corrosion rate of the alloys by 3–4 orders of magnitude. The MAO coating on ZK60 alloy showed better corrosion protectiveness than that on the AZ series alloys due to the incorporation of different alloying elements in the coating, especially the Zn and Al elements, which are from the Mg substrate. The corrosion performances and mechanisms of the uncoated and MAO‐coated Mg alloys are interpreted in terms of the microstructure and phase/chemical compositions of both the substrates and coatings. [ABSTRACT FROM AUTHOR]

There has been a constant requirement from the clinic to develop biomedical titanium (Ti) implants with high osteogenic ability. In this study, we clarified a novel mechanism of how MAO (microarc oxidation) coating of Ti implants facilitates osteogenic differentiation of human bone marrow mesenchymal stem cells (hB-MSCs) by activating ERK1/2-miR-1827-Osterix signaling pathway in vitro. MAO surface of titanium implant was more favorable to promote osteogenic differentiation than SLA and AOS coating. Besides, titanium implants regulated hB-MSCs osteogenesis through the p38 MAPK pathway and ERK1/2 might be the most efficient target. Furthermore, MAO coating induced osteogenic differentiation though ERK1/2-miR-1827 pathway. Finally, we verified miR-1827 regulated osteogenic differentiation partially through Osterix. Our study reveals novel insights that MAO surface of titanium implant is a prior choice for biomedical trial and for its use in periprosthetic osteolysis (PIO) treatment in an evidence-based rationale. [ABSTRACT FROM AUTHOR]