Plasma Electrolytic Oxidation Technique Research Articles

Analyzing PEO anodization time to monitor coatings phases, composition, morphology, thickness, and microhardness during the growth of TiO2 pores on the CP-Ti surface

The objective of this study was to develop an oxide coating on commercially pure titanium using the plasma electrolytic oxidation (PEO) technique. During the surface treatment process, the time value was varied for 1, 10, 15, 30, 45, and 60 min. The PEO treatment was carried out at a limited current of 2.5 A and a voltage of 300 V. The coatings exhibit the anatase and rutile crystalline structures of TiO2. The coating produced for longer treatment times has higher concentrations of rutile, resulting in surface hardening. The thickness and the roughness of the coatings increased with the increase in treatment time, but there was a reduction in the size of the pores per unit area.

Plasma electrolytic oxidation of AZ31 magnesium stents for degradation rate control

Cardiovascular disease caused by the accumulation of atheroma plaques in the coronary arteries and the subsequent decrease in the blood flow through the affected vessel, known as atherosclerosis, is responsible for a high percentage of deaths worldwide. Angioplasty is practiced to treat atherosclerosis which involves inserting a stent inside the occluded vessel to expand it and restore normal blood flow. In this work, temporary biodegradable stents made of AZ31 magnesium alloy have been fabricated using photo-chemical etching. The stents were coated via plasma electrolytic oxidation (PEO) technique. The radial strength of the stents was evaluated by cyclic compression, and the corrosion protection provided by the PEO coatings was studied by electrochemical and in vitro corrosion tests respectively. The stents showed an optimal maximum radial force of 0.147 N/mm and revealed elastic recuperation lower than 7 % of the total deformation after expansion. The applied PEO coating helped to control the corrosion of the magnesium alloy, delaying its initiation and, once it has started, decreased the degradation rate compared with the bare AZ31 samples. Thus, the stents treated with the PEO coatings developed in this research present promising results for their use as temporary medical devices used in angioplasty.

Enhancing corrosion resistance in Mg[sbnd]Li alloy through plasma electrolytic oxidation coatings — Exploring the impact of ionic liquids (BmimBF4)

The wide application of MgLi alloys is limited by the poor corrosion resistance, which needs to be improved by surface treatment. Plasma electrolytic oxidation (PEO) method is one of the most promising methods for the formation of oxide coatings on MgLi alloys. However, the conventional PEO technique with high energy consumption causes poor coating compactness and hampers efforts to enhance corrosion resistance. In this study, various concentrations of ionic liquids (1-butyl-3-methylimidazolium tetrafluoroborate, BmimBF4) are introduced into the concentrated alkaline electrolyte to facilitate the formation of a PEO coating on the surface of LA91 magnesium‑lithium (MgLi) alloy. The influence of BmimBF4 on PEO coatings has been investigated. The results indicate that a concentrated electrolyte significantly lowers the working voltage of PEO, thereby enhancing energy efficiency. Uneven adsorption on the substrate surface, resulting from the low concentration of BmimBF4 (≤20 mL/L) in the electrolyte, induces partial discharge, leading to high surface roughness and the formation of large pores. However, when an excessive amount of BmimBF4 (>20 mL/L) is present, it uniformly adsorbed onto the substrate surface during the initial stage of PEO process, forming a corrosion inhibitor layer. This leads to a consistent discharge on the surface of substrate throughout the entire PEO process, resulting in a reduction in both surface roughness and micropore size. Among these coatings, the one prepared in an electrolyte containing 20 mL/L BmimBF4 exhibits the highest contact angle (66.8° ± 3.8°) and the best long-term corrosion resistance (hydrogen evolution rates <0.02 mL·cm−2·h−1). These properties can be attributed to the physical and chemical adsorption of BmimBF4, which contains hydrophobic long alkyl chains, as well as the maximum thickness with extended discharging channels. This study offers a guiding strategy for further reducing energy consumption and enhancing the corrosion resistance of PEO coatings.

Unraveling crystalline phases, morphology, hardness, and adhesion of PEO anodic coatings on Ti-15Nb alloy surface

This study aims to create a coating of oxide (with Ca, P, and Mg) on the Ti-15Nb alloy using the plasma electrolytic oxidation (PEO) technique. The voltage value was varied during the surface treatment process (200, 250, and 300 V). The PEO treatment was performed using a limited current of 2.5 A for 60 s. The films have the anatase and rutile crystalline structures of TiO2, where rutile increases the hardness of the coatings. All coatings are hydrophilic in contact with distilled water and have poor adhesion to the substrate.

In vitro tribological behavior and corrosion resistance of SiO2/TiO2/ZrO2 coatings formed on the tantalum substrate using plasma electrolytic oxidation for orthopedic implant applications

Tantalum (Ta) is widely used in orthopedic and dental implants due to its remarkable stability, biocompatibility, and mechanical properties. However, in physiological environments, even stable and noble metals can form harmful complexes. This study aimed to enhance the surface mechanical, topographical features, and biocompatibility of Ta by applying a coating of ZrO2, SiO2, and TiO2 nanoparticles using the plasma electrolytic oxidation (PEO) technique. A composite layer was formed on the Ta substrate through PEO at a constant voltage of 500 V with duty cycles of 20% and 40% for 10 min. Evaluation of the coated samples revealed significant improvements in various properties. The nanohardness of the Ta surface at a 40% duty cycle was found to be 6.7 times higher than that of the uncoated Ta sample. The stiffness of the coated Ta at a 40% duty cycle was 2.4 times higher than the uncoated Ta. However, the surface roughness of the 40% duty cycle-coated Ta was higher compared to other samples. The coated Ta at a 40% duty cycle exhibited a higher surface roughness and wettability, which can potentially enhance cell adhesion and proliferation. The surface morphology properties were analyzed using FESEM, which revealed the presence of a composite layer composed of ZrO2, SiO2, and TiO2 nanoparticles on the Ta substrate. Additionally, the contact angle test demonstrated that the coated Ta samples had decreased contact angles from 86° to 9°, indicating increased hydrophilicity compared to the uncoated Ta. Corrosion resistance was assessed through potentiodynamic polarization test and electrochemical impedance spectroscopy. The corrosion resistance of the coated Ta at 20% and 40% duty cycles increased from 0.78 × 103 Ω cm2 to 8.85 × 103 and 9.4 × 103 Ω cm2, respectively, indicating the formation of a nobler layer on the Ta surface. Biocompatibility studies using MG-63 cells showed enhanced cell adhesion and viability on the surface of the 40% duty cycle-coated Ta, attributed to its higher surface roughness and hydrophilicity. The cell viability for the coated samples (Ta-20 and Ta-40) after 3 days of culture was 95% and 98%, respectively, compared to 89% for the uncoated Ta sample. These findings demonstrate that the SiO2/TiO2/ZrO2 ceramic coatings significantly improve the mechanical properties, corrosion resistance, surface morphology, and hydrophilicity of Ta implants. Such enhancements have the potential to extend the lifetime of Ta implants in dental and orthopedic applications.

Total Specific Energy as a New Figure of Merit for the Design of Porous TiO2 Surfaces Synthesized via Plasma Electrolytic Oxidation

The plasma electrolytic oxidation (PEO) is a variation of the anodic oxidation technique, one of the simplest and most economical methods to obtain crystalline and porous TiO2 coatings. Beyond the conventional approach of establishing a relationship between the variables of synthesis and the characteristics of the TiO2 coatings, a new figure of merit was defined in the present work for the synthesis of TiO2 coatings by PEO: the total energy per unit of surface (TSE). A strong relationship was found between TSE and the TiO2 anatase fraction. The application of TSE, together with the known influence of the variables of synthesis on the coating characteristics, allows a prediction, previously to the anodization and with reasonable precision, of the anatase fraction and the pore diameter of the coating. Applying the TSE new concept, three coatings were successfully designed. This is the first step toward a surface design using the PEO technique.

A comparative analysis of Cr(VI) reduction with Cu2O, ZnO and Fe2O3 coatings grown by PEO

Coatings on copper, zinc and stainless-steel substrates were fabricated using the plasma electrolytic oxidation (PEO) technique and their photocatalytic activity was evaluated in the reduction of Cr(VI), a highly toxic agent present in wastewater from industrial processes such as electroplating, manufacture of textile dyes, wood curing, and leather tanning. The concentration of hexavalent chromium in drinking water has been regulated to a maximum value established by national and international legislation of 0.05 ppm. The strategy of reduction to less toxic species such as Cr(III), followed by its precipitation in a basic medium, use several methods derived from chemistry, physics and biology for the treatment of water contaminated with this material. In the present work, some coatings of copper, zinc, and iron oxides were obtained over the corresponding metal sheets exposed to PEO, which were tested in a heterogeneous process of advanced oxidation with 1 ppm Cr(VI) solution under ultraviolet radiation. Thus, a reduction rate to Cr(III) close to 100 % in 60 min was obtained.

Plasma Electrolytic Oxidation Treatment of AZ31 Magnesium Alloy for Biomedical Applications: The Influence of Applied Current on Corrosion Resistance and Surface Characteristics

Magnesium alloys are an exciting challenge for the biomaterials field given their well-established biodegradability and biocompatibility. However, when exposed to biological fluids, their rapid degradation and hydrogen release are the main drawbacks for clinical applications. This work aimed to investigate the influence of the current density applied during the plasma electrolytic oxidation (PEO) treatment on the durability of an AZ31 magnesium alloy. In particular, specific interest was directed to the degradation rate undergone by the PEO coating, obtained under two different current density conditions, when exposed to Hank’s solution at 37 °C to simulate the physiological environment, employing the techniques of potentiodynamic polarization and electrochemical impedance spectroscopy. Experimental results highlighted that the plasma electrolytic oxidation technique resulted in an improvement in the corrosion resistance of the magnesium alloy in the test solution. The current density affected the morphology of the coating. In particular, the anodic oxide coating obtained by applying the highest current density showed a higher thickness and fewer but larger pores, while the lowest current density generated a thinner PEO coating characterized by several but smaller pores. Surprisingly, the best corrosion resistance has been exhibited by the anodic oxide coating grown at the highest current density.

An ionic liquid-assisted strategy for enhanced anticorrosion of low-energy PEO coatings on magnesium–lithium alloy

A low-energy plasma electrolytic oxidation (LePEO) technique is developed to simultaneously improve energy efficiency and anti-corrosion. Ionic liquids (1‑butyl‑3-methylimidazole tetrafluoroborate (BmimBF4)) as sustainable corrosion inhibitors are chosen to investigate the corrosion inhibition behavior of ionic liquid (ILs) during the LePEO process for LA91 magnesium–lithium (Mg–Li) alloy. Results show that the ionic liquid BmimBF4 participates in the LePEO coating formation process, causing an increment in coating thickness and surface roughness. The low conductivity of the ionic liquid is responsible for the voltage and breakdown voltage increases during the LePEO with IL process (LePEO-IL). After adding BmimBF4, corrosion current density decreases from 1.159 × 10−4 A·cm−2 to 8.143 × 10−6 A·cm−2. The impedance modulus increases to 1.048 × 104 Ω·cm−2 and neutral salt spray remains intact for 24 h. The superior corrosion resistance of the LePEO coating assisted by ionic liquid could be mainly attributed to its compact and thick barrier layer and physical absorption of ionic liquid. The ionic liquid-assisted LePEO technique provides a promising approach to reducing energy consumption and improving film performance.

EFFECT OF NANOPARTICLE ADDITIVES ON THE MICROSTRUCTURE AND CORROSION PROPERTIES OF PLASMA ELECTROLYTIC OXIDATION COATINGS ON MAGNESIUM ALLOYS: A REVIEW

In recent years, nanoparticles are increasingly used in scientific research and have attracted the attention of many scholars. In this paper, ceramic coatings were prepared on the surface of magnesium and its alloys using the plasma electrolytic oxidation (PEO) technique. We investigated different nanoparticles added to the electrolyte and explored the mechanism of nanoparticle effects on the formation and protection mechanism, morphology and structure, thickness and roughness, and electrochemical corrosion behavior of the coatings. The results show that the coating morphology changes significantly and the surface is more uniform and dense due to the addition of nanoparticles in the electrolyte. The addition of nanoparticles increases the thickness of the coating to some extent, but as its addition to the electrolyte increases, the coating thickness decreases. Since the prepared coatings inevitably produce micropores and microcracks, which may have an impact on the corrosion resistance of the coatings, how to improve the corrosion resistance of the coatings has become a common concern. Nanoparticles can participate in the growth of the coating and will enter the micropores under discharge conditions. On the one hand, they can play a role in closing the porous layer, and on the other hand, they will form some special structures on the surface, thus improving the corrosion resistance of the coating. Finally, we outlook the problems and challenges of the PEO technique in practical applications.

Nano Graphene Oxide Embedded Hydroxyapatite Coating on AZ91D Mg Alloy at Various Voltage for Bone Implant Application​

Magnesium (Mg) and its alloys have been widely explored for biomedical applications as future biodegradable implant materials. Furthermore, a facile plasma electrolytic oxidation (PEO) technique was used to create biodegradable hydroxyapatite (HA) and nanographene oxide (nGO) coating on AZ91D Mg alloy. However, Mg and its alloy are vulnerable to the physiological environment, resulting in an untimely loss of mechanical power. Other than that, the coating factor for clinical application, such as HA, has barriers in hardness, strength, and wear resistance. This paper focuses on the physical properties and surface morphology of HA/nGO coating on AZ91D Mg alloy through PEO coating to solve the problem. The AZ91D Mg alloy was coated with HA/nGO using the PEO method at constant HA/nGO concentration and coating time, with variable voltages (115V, 230V, 345V, and 460V). Surface morphology analysis, elemental composition analysis and surface roughness, and were evaluated. Finally, the effect of a particular voltage level on the surface roughness at the constant coating time of 10 minutes indicates the surface roughness values of 1.6667 μm at 345V were obtained and demonstrate that HA/nGO samples are well disseminated at 345V coating compared to the other voltages.

Flat Absorber Black PEO coatings on Ti6Al4V for spacecraft thermal control application

Black appearance and flat absorber, i.e., high solar absorptance (αs) and high IR emittance (εir) surfaces, are essential for optical benches and optical mounts in astronomical and scientific payloads/spacecraft. Generally, these optical benches and optical mounts are fabricated by Ti6Al4V alloy due to its superior mechanical and thermal properties. However, bare Ti6Al4V is restricted for spacecraft thermal control applications due to its low emittance, intermediate absorptance, and moderate corrosion resistance behaviors. Hence, plasma electrolytic oxidation (PEO) technique was utilized to develop black and flat absorber coatings on bare Ti6Al4V alloy. Sodium silicate (SS), sodium hypophosphate (SHP), and potassium fluoride (KF) were used for the preparation of the electrolytic bath. Process parameters such as current density, duty cycle, frequency, the concentration of electrolytes, and duration were judiciously altered to get uniform PEO coatings with the flat absorbing property. Six numbers of PEO coatings were finally chosen for further in-depth characterizations as they showed adequate flat absorbing property. The phase composition, microstructure, roughness, and wettability of those PEO coatings were thoroughly studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), profilometry, and water contact angle measuring techniques, respectively. Thermo-optical properties viz., εir and αs of the coatings were recorded by portable IR emissometer and solar reflectometer, respectively, and electrical sheet resistance was measured by two probe method. The Nanomechanical properties of the coatings, such as modulus (E) and nanohardness (H), were evaluated by the nanoindentation technique. The PEO coatings were also investigated with respect to potentiodynamic polarization to investigate corrosion resistance of the PEO coatings. The highest εir value of PEO coating was achieved as 0.87 for a 20% duty cycle with a combination of SS + SHP electrolytes, while the maximum αs value was achieved as 0.83 for the same 20% duty cycle with a combination of SS + SHP + KF electrolytes.

Achieving high-efficiency electrically insulating ceramic layer formed on SiCp/Al composite by bipolar pulsed PEO for novel integrated strategy

Thermal conductive insulating ceramic materials are urgently needed in the packaging applications for modern electronic devices owing to their multi-functionality. The electrically insulating Al2O3 ceramics with large thickness and high compactness is designed on SiCp/Al baseplate via plasma electrolytic oxidation (PEO) technique, which provides a new idea for the package structure of the IGBT power module. However, porous characteristics of PEO inorganic ceramics hinder effective electrical insulation and heat conduction in practical applications. Herein, the bipolar pulsed (BP) and unipolar pulsed (UP) PEO are tailored to obtain the ceramics respectively. In contrast, the BP mode enables the ceramic layer significantly thickened and densified due to the soft sparking discharge. Combined with outstanding electrical resistivity over 1012 Ω·cm, high breakdown voltage of 716 ± 38 V, high dielectric strength of 15.9 ± 0.8 V/μm, the BP ceramic layer exhibits superior performance in electrical insulation. Moreover, the BP shows excellent thermal cycling stability (>200 cycles), quite good thermal stability, and dielectric stability in the temperature range of 25 °C to 300 °C to realize high-temperature electrical insulation. This work paves a novel way to design and optimize power electronic module package materials and structures.

Multifunctional TiO2 coatings developed by plasma electrolytic oxidation technique on a Ti20Nb20Zr4Ta alloy for dental applications.

A newly developed β-Ti alloy based on the Ti-Nb-Zr-Ta system (Ti20Nb20Zr4Ta) has been subjected to Plasma Electrolytic Oxidation (PEO) treatment to obtain a multifunctional ceramic-like (TiO2) coating with superior tribocorrosion (wear and corrosion) resistance and improved biocompatibility. For this aim, elements such as Ca, P, and Ag NPs have been incorporated into the oxide film to obtain bioactive and biocide properties. The chemical composition and morphology of the TiO2-PEO coating was characterized, and its multifunctionality was addressed by several means, including antibacterial activity assessment, formation of bone-like apatite, metallic ion release evaluation, in vitro cellular response analysis, and corrosion and tribocorrosion tests in artificial saliva. The developed coatings enhanced the corrosion and tribocorrosion resistance of the bare alloy and exhibited antibacterial ability with low cytotoxicity and negligible ion release. Furthermore, they were able to sustain MC3T3-E1 preosteoblast viability/proliferation and osteogenic differentiation. Altogether, the results obtained demonstrate the potential of the TiO2 coating incorporating Ca, P, and Ag NPs to be used for dental applications.

The Tribological Behavior of Nanocrystalline TiO2 Coating Produced by Plasma Electrolytic Oxidation

Nanocrystalline TiO2 coatings were produced on titanium substrates using the plasma electrolytic oxidation technique. The effects of frequency, duty cycle, and type of applied current (pulse and direct) were evaluated on the microstructure of the coatings and the tribological behavior of the samples. Morphological evaluations demonstrated that the pancake structure was developed from coatings created with a unipolar pulsed current. However, a volcano-like surface morphology resulted from a constant current. The XRD analysis results showed that the coatings were composed mainly of the rutile phase by 77.80-96.34 wt. %. In comparison, 22.20 wt. % of the anatase phase was identified in samples produced with direct current. These phases were determined to be nanocrystalline (29.5-48.3 nm), which led to significant improvements in the tribological properties. The sample produced with direct current had larger pores, greater roughness, and a four-times higher thickness than samples created with unipolar current. Furthermore, the tribological study results showed that wear resistance was significantly higher in the unipolar pulsed current coatings than in those obtained with direct current. Moreover, samples made at a higher frequency and lower duty cycle showed better tribological behavior.

Corrosion inhibition of Ti6Al4V alloy by a protective plasma electrolytic oxidation coating modified with boron carbide nanoparticles

Plasma electrolytic oxidation (PEO) is a cost-effective and versatile technique to achieve protective oxide coatings in light metals. Composite coatings containing B 4 C nanoparticles were produced by the PEO technique on a Ti6Al4V alloy. The influence of nanoparticles on the microstructure and corrosion resistance of the prepared ceramic composite coatings, as well as its incorporation mechanism into the PEO layer, were investigated. B 4 C nanoparticles were added to aluminate-based electrolytes and a pulse power supply was used as a constant voltage regime to obtain PEO composite coatings. Improvement in corrosion protection was also assessed by electrochemical impedance spectroscopy (EIS) and polarization tests, illustrating that a reduction in the corrosion resistance ratio was 8 for the composite coating compared to 16 for the sample without nanoparticles, after three weeks of immersion. The effect of nanoparticles on the phase composition was examined by X-ray diffraction (XRD) tests. Moreover, scanning electron microscopy (SEM) images illustrated the capability of B 4 C nanoparticles in filling the inherent pores of PEO coatings. • Fabrication of plasma electrolytic oxidation coatings modified with B 4 C nanoparticles on Ti6Al4V alloy • The significant role of electrophoretic force and trapping in the melted oxide layer on particle absorption. • Sealing the inherent pores of the PEO coating by the B 4 C nanoparticles. • Employing the voltage of 400V protects the PEO composite coatings upon three weeks in 3.5% NaCl.

Adhesive bond strength of PEO coated AA6060-T6

Adhesive bonding is a key joining technique for aluminium alloy components in the automotive industry. Plasma Electrolytic Oxidation (PEO) is an emerging surface treatment for the protection of metal alloys including those of aluminium. This work set out to assess the adhesive bond strength and behaviour of PEO coated aluminium alloy AA6060-T6. Thin (15 to 25 μm) oxide coatings were produced on AA6060-T6 by Plasma electrolytic Oxidation (PEO) in phosphate and silicate-phosphate electrolytes. The coatings were characterised extensively, then adhesively bonded in lap-shear joints and loaded to failure under tensile mode to evaluate the bond strength of adhesively bonded coated samples. Surface fracture analysis was carried out to determine the failure modes of the lap-shear joints. The failure mechanism and strength of the coated joints was compared to the characteristic features of the coatings, in an attempt to identify governing properties. It was found that PEO coatings could withstand high loading; however, the strength of the bonded joints was governed by the cohesive strength of the oxide layers. All coatings produced in the phosphate and thicker coatings produced in the silicate-phosphate electrolyte ultimately experienced cohesive failure within the oxide region. Thinner silicate-phosphate coatings electrolyte displayed a favourable failure mechanism with fracture occurring within the adhesive, which highlights the possibility of PEO technique to be used for adhesively bonded aluminium alloy parts.

Synthesis, microstructure and biodegradation behavior of MgO-TiO2-PCL nanocomposite coatings on the surface of magnesium-based biomaterials

In this study, a magnesium oxide-titanium dioxide (MgO-TiO2) nanocomposite film was successfully applied to pure magnesium (Mg) surface using the plasma electrolytic oxidation (PEO) technique in an electrolyte solution containing TiO2 nanoparticles. A uniform top-layer polycaprolactone (PCL) coating was eventually formed on the PEO-treated Mg through a dip-coating process. The results indicated that the porous nature of the PEO-coated samples could not provide the desired corrosion resistance in simulated body fluid (SBF). However, the deposition of the top-layer PCL coating (utilizing 8wt% PCL) over the MgO-TiO2 nanocomposite coating greatly improved the corrosion resistance of the Mg substrate. The proposed PCL top-layer coated MgO-TiO2 nanocomposite film could be considered as a promising candidate for the surface modification of Mg-based biodegradable implants. Due to the microstructural and macrostructural porous nature of the PEO film, this coating can be further used on the surface of biodegradable implants not only to control the degradation rate but also to deliver therapeutic molecules.

Influence of Process Parameters on the Tribological Behavior of PEO Coatings on CP-Titanium 4+ Alloys for Biomedical Applications

Wear resistant ceramic coatings were generated on novel commercially pure titanium grade 4+ alloys by the plasma electrolytic oxidation technique (PEO) in an aluminate and zirconia containing electrolyte. The coatings were obtained adopting a full regular two-level factorial design of experiments (DoE) varying the PEO process parameters current density, repetition rate and duty cycle. The generated coatings were characterized with respect to its wear resistance and mechanical properties by reciprocal ball-on-flat tests and nanoindentation measurements. Thickness, morphology and phase formation of the PEO coatings was analyzed by scanning electron microscopy (SEM/EDS) and X-ray diffraction. XRD results indicate the formation of crystalline aluminium titanate (TiAlO) as well as t-ZrO and alumina leading to an increase in hardness and wear resistance of the PEO coatings. Evaluation of the DoE’s parameter interaction shows that the main effects for generating wear resistant coatings are current density and repetition rate. In particular, the formation of mechanically stable and adhesive corundum and zirconia containing coatings with increasing current density and frequency turned out to be responsible for the improvement of the tribological properties. Overall, the PEO processing significantly improves the wear resistance of the CP titanium base alloy.

Fe-, Ni-containing ceramic-like PEO coatings on titanium and aluminum: Comparative analysis of the formation features, composition and ferromagnetic properties

Fe-, Ni-containing coatings have been formed on aluminum and titanium by the plasma electrolytic oxidation (PEO) technique in slurry electrolytes containing colloidal particles of Fe(III) and Ni(II) compounds including hydroxides. Their composition, surface morphology, and magnetic properties were studied and compared. In both cases, the concentration of iron, nickel, and substrate metal is higher, and the oxygen concentration is lower in the pores of the coatings than their average concentration over the surface. In the case of titanium, the electrolyte and substrate metals are concentrated in the pores (at. %: 38.6 Fe, 4.7 Ni, 19.5 Ti) in the form of micro- and nanosized crystallites. In the pores of the coating on aluminum, metals are concentrated in the composition of the layers lining the pores (at. %: 15.3 Fe, 50.6 Ni, 18.8 Al). The values of the coercive force and the saturation magnetization of the ferromagnetic component at 300 K for the aluminum sample (Нс = 38 Oe, M*s = 2.8 × 10−4 emu/g) are significantly lower than those for the titanium sample (Нс = 73 Oe, M*s = 7.8 × 10−3 emu/g). The discrepancy between the ferromagnetic properties of the aluminum and titanium samples correlates with the difference in the elemental composition of the pores and the presence/absence of crystallites in the pores. More pronounced ferromagnetic properties of titanium samples can be associated with the presence of crystallites in the coating pores.