Corrosion Resistance Of Films Research Articles

Preparation of Zn1-xCrxO resistive switching film and its corrosion behavior in 3.5 wt.% NaCl solution

Zn1-xCrxO resistive switching film with different Cr content was prepared on SS304 substrate by sol–gel method combined with spin plating and heat treatment. The surface morphology, composition, structure, semiconductor type and oxygen vacancy concentration of Zn1-xCrxO films were observed and analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Mott-Schottky curves, X-ray photoelectron spectroscopy (XPS) electron paramagnetic resonance spectroscopy (ESR) and density functional theory (DFT) calculation. And the corrosion resistance of Zn1-xCrxO film were investigated by polarization curves and electrochemical impedance spectroscopy (EIS). The results show that the prepared Zn1-xCrxO films have a uniform dense surface which belongs to n-type semiconductor type, and the oxygen vacancy concentration in the films increases with the increase of Cr content. With the increasing of Cr content, the corrosion resistance of films is decreased. During the immersion process, the corrosion resistance of Zn1-xCrxO film is firstly increased and then decreased with increasing immersion time. By applying immersion and polarization treatment the corrosion resistance of Zn1-xCrxO film could be regulated between the high and low resistance states (HRS and LRS) due to the creation and disappearance of oxygen vacancies in the film.

Improved corrosion resistance of MAO coating on Mg-Li alloy by RGO modified silanization

The inherent micropores and microcracks in the micro-arc oxidation (MAO) film on the surface of Mg-Li alloy limit the corrosion resistance of the film in corrosive environments. In this work, the double-layer micro-arc oxidation/3-glycidoxypropyltrimethoxysilane (KH560) composite film was prepared on the surface of the LA103Z Mg-Li alloy by MAO and silanization treatments. Based on this, the modification with reduced graphene oxide (RGO) to the KH560 film was studied and the corrosion resistance of the film was investigated. The results show that the silane film prepared is uniform and complete which fills up the micropores and microcracks of the MAO film, enhancing the shielding effect of the film. Moreover, the RGO modification increases the thickness of the KH560 film and the corrosion resistance of the composite film significantly in 3.5 wt% NaCl solution.

Structure and properties of Si and N co-doping on DLC film corrosion resistance

Three species of diamond-like carbon (DLC) film were systematically examined in NaCl solution for their anticorrosion properties. Si&N&H-DLC has better electrochemical characteristics and salt spray corrosion testing results than the substrate and two species DLC films in NaCl solution. Due to the successive growth of Si, N, and H-DLC, there is a well-bonded Si–N interface and the formation of Si oxides. The Si&N&H-DLC film exhibits extremely high charge transfer resistance, exceeding 106 Ω/cm2. A salt spray test shows that the Si&N&H-DLC film presents a lower rate in NaCl solution in comparison to the substrate and the other two species of DLC films. As a result, the Si&N&H-DLC film significantly improved the corrosion performance of the substrate.

Preparation of corrosion-resistant hydrophobic composite films on magnesium alloy

ABSTRACT Magnesium alloy has attracted wide attention for excellent properties but poor corrosion resistance hinders its application. The method of preparing high-performance corrosion-resistant films with low cost and easy operation is significantly crucial to the corrosion protection of magnesium alloy. By synthesizing zeolite film directly on AZ91D magnesium alloy, the work presented a simple, efficient and environmentally-friendly preparation method. In this study, a one-step synthesis method of multi-structure composite film on AZ91D magnesium alloy was explored. The prepared film surface had dense Mg(OH)2 bottom layer and K2Al2Si4O12·xH2O upper layer with porous support microstructure. Compared with the substrate, the corrosion current on the sample surface modified by stearic acid was reduced by about three orders of magnitude, and the corrosion inhibition rate reached 99.96% with a stable contact angle of about 125°. The results showed the excellent corrosion resistance and stable hydrophobicity of the prepared sample.

The effect of the Nb concentration on the corrosion resistance of nitrogen-containing multicomponent TiZrTaNb-based films in acidic environments

Multicomponent as well as high-entropy-based nitrides have received increasing interest in the field of materials science and engineering. The structural characteristics of these compounds result in a mix of covalent, metallic, and ionic bonds that give rise to a number of attractive properties including high hardness, electrical and thermal conductivities as well as chemical stability. These properties render these materials promising candidates for various industrial applications involving harsh operating conditions. Herein, the corrosion resistances of dc magnetron sputtered nitrogen-containing TiZrTaNby thin films with Nb content ranging from 8.0 to 24.5 at% have been investigated to provide insights regarding the corrosion resistances of multicomponent systems containing more than one passive element. The corrosion resistances and anodic behavior of the films were examined by electrochemical means in 0.1 M H2SO4 and 0.1 M HCl solutions. The results demonstrate that despite the significant differences in the concentration of one of the two main passive elements in the films i.e., Nb, the corrosion resistance did not differ significantly between the films. To provide insights into this phenomenon, the surface chemical state and composition of the prepared films were probed using X-ray photoelectron spectroscopy. It was shown that all samples exhibited Ta-rich surfaces after positive polarization up to 3.0 V vs. Ag/AgCl (3 M NaCl) as a result of the anodic dissolution of Zr and Ti. The thickness of the oxide layer formed upon different anodic polarization was studied using transmission electron microscopy, while complementary electrochemical impedance studies were performed. The extent of Nb dissolution from the surface of the films was, on the other hand, found to be small. These findings highlight the dominant role of Ta in the passivation of the films and demonstrate the minor effect of Nb concentration on the corrosion resistances of the films. However, it was demonstrated that the presence of Nb was still important for the corrosion resistance of the films above 1.4 V vs. Ag/AgCl (3 M NaCl), when replacing Nb with Cr, due to transpassive dissolution of Cr. These results facilitate the design of highly corrosion resistant multicomponent nitrides containing more than one passive element.

Study on Preparation of Micro-Arc Oxidation Film on TC4 Alloy with Titanium Dioxide Colloid in Electrolyte

The micro-arc oxidation film on TC4 alloy was prepared using a multifunctional micro-arc oxidation (MAO) power source. The effect of nano-titania colloid addition on the growth process, microstructure, and comprehensive mechanical properties of titanium alloy micro-arc oxidation films was studied by gradient concentration. The results show that, with the increase in titanium dioxide colloid content, the intensity of the discharge phenomenon during the MAO process increases, and the average current density gradually increases. The film thickness is gradually increased from 111.06 μm to 159.8 μm, and the roughness first decreases and then increases. The XRD results show that the rutile content in the film layer is increased with titanium dioxide colloid in the electrolyte. This resulted in an increase in the density of the film, and lead to the corrosion resistance of film improved. When the concentration of titanium dioxide colloid is 1.5 g/L, the comprehensive performance of the film is the best.

Effects of Cr on pitting corrosion resistance and passive film properties of austenitic Fe–19Mn–12Al–1.5 C lightweight steel

The effects of Cr on microstructure, pitting corrosion resistance, and passive film properties of austenitic Fe–19Mn–12Al–1.5 C–(0–7.3 wt%)Cr lightweight steel were studied. Microstructural analysis indicated that the optimal Cr content for a homogeneous microstructure was 5 wt%. Passive film analysis showed that alloying Cr up to 5 wt% in the matrix increased both the Cr and Al content in the passive film and increased the ratio of oxide to hydroxide in the film. Thus, the Fe–19Mn–12Al–1.5–5 Cr alloy exhibited the highest resistance to pitting corrosion among the investigated alloys due to the homogeneous microstructure and a (Cr,Al)-enriched passive film.

Heat Treatment Effect on Corrosion Resistance of Mg Coating Film on Hot-Dip Aluminized Steel

Magnesium was coated on a hot-dip aluminized steel plate by the physical vapor deposition process. The effects of intermetallic compounds formed by heat treatment and crystal orientation on corrosion resistance were investigated. Furthermore, corrosion resistance was evaluated through various electrochemical corrosion tests, and corrosion products were investigated as well. In the salt spray test, the heat-treated Mg film showed higher corrosion resistance than non heat-treated Mg film as well as hot-dip aluminized steel plate due to various intermetallic compounds and increased interplanar spacing of aluminum. Moreover, higher film resistance in heat-treated Mg was confirmed through electrochemical impedance spectroscopy. Based on the results, the corrosion mechanism of the heat-treated Mg was suggested where MgAl2O4 played a major role in shielding corrosion factors in the intermediate stage of corrosion. The heat-treated Mg showed a robust potential as an alternative corrosion-resistant film to replace hot-dip and electroplated film.

Study on microstructure, mechanical properties and corrosion resistance of NbCN-Cu composite films

In this research, NbCN-Cu films with different Cu contents were prepared by multi-target confocal RF magnetron sputtering. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray Photoelectron Spectroscopy (XPS), Raman spectrometry, Energy Disperse Spectroscopy (EDS), nano-indentation, and electrochemical workstation were used to characterize and analyze the microstructure, mechanical properties and corrosion resistance of the films. The results show that the NbCN-Cu composite films consist of crystalline face-centered cubic(fcc) Cu, face-centered cubic(fcc) NbCN, hexagonal close-packed(hcp) NbCN, and amorphous graphite and CNx phases. When Cu content was 2.6 at.%, a coherent interface was detected between fcc-Cu and fcc-NbCN, hcp-NbCN, and dislocations were detected at the coherent interface when Cu content increased to 9.5 at.%. With the increase of Cu content, the microhardness of the film first increased and then decreased. NbCN-Cu composite film with Cu content of 2.6 at.% had the highest hardness of 32.8 GPa and remarkable corrosion resistance. The self-corrosion potential of the film was 0.18 V and self-corrosion current density was 2.29 × 10−6 A/cm2.

Hydroxyapatite film prepared by hydrothermal method on layered double hydroxides coated Mg Alloy and its corrosion resistance

Hydroxyapatite (HA) bioactive film is a standard surface modification method for biodegradable Mg alloys. However, the corrosion resistance of HA film prepared before was mediocre, and the preparation process was complicated. In this study, hydroxyapatite film was prepared for the first time on layered double hydroxides (LDHs) coated Mg alloy by hydrothermal method. The structure and composition of LDHs and HA films were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The corrosion resistance and immersion behavior of the films in simulated body fluid (SBF) were investigated by using potentiodynamic polarization curve, electrochemical impedance spectroscopy (EIS) techniques. The effects of different pH and calcium to phosphorus molar ratios (Ca/P ratios) of HA hydrothermal solution were investigated. The experimental results show that HA films appear in petal-like, filamentous and flower-like. The corrosion resistance of the film first increases and then decreases with the pH from weak acid to alkaline. With the increase of the Ca/P ratio, the film is gradually denser, and the protective effect is enhanced. The immersion test results show that after 7 days of immersion, the impedance modulus of the composite film is about 5 × 103 Ω·cm2, which is ten times higher than the single LDHs film. The effects of the pH and Ca/P ratio of the HA hydrothermal solution on the preparation of HA film are simply explained by thermodynamic theory. The Mg-LDHs-HA composite film provide a corrosion protection barrier for Mg substrate and HA film is biologically active. The barrier effect and the mineralization behavior provide a better corrosion protection for Mg substrate.

Effect of Ammonia Addition on the Growth of an AlO(OH) Film during Steam Coating Process

Al alloys possess excellent physical and mechanical properties, such as low density, high specific strength, and good ductility. However, their low corrosion resistance limits their use in corrosive environments. The steam coating process has attracted considerable attention as a new coating technology that can improve the corrosion resistance of Al alloys. This surface treatment technology uses steam to form a corrosion-resistant film on Al alloys. However, a decrease in the processing time, which can result in a lower cost, is needed for the practical application of the steam coating process. In this study, an Al-Mg-Si alloy is used as the base material, and ammonia is added to the steam source to increase the film formation rate. By adding ammonia (0.5 mol/L) to the steam source, the rate constant, K, for film formation increases 1.82 times compared to that of the pure-water-only treatment. Field emission scanning electron micrographs of the film surface confirms that the crystal morphologies of the crystals change from rectangular to parallelepiped shape with increasing process time by ammonia addition. Furthermore, X-ray diffraction patterns show that AlO(OH) crystals are successfully synthesized without byproducts, even when ammonia is added.

Corrosion Behavior of Mg(OH)2/Mg–Al Layered Double Hydroxides/AlO(OH) Composite Film Prepared by Steam Coating on Mg Alloy AZCa612

This study investigated the corrosion behavior of the corrosion-resistant films steam coated on AZCa612 magnesium alloy. The film samples were corroded by immersing them in 5 wt% NaCl aqueous solution for a predetermined time. The corroded films were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, glancing angle X-ray diffraction, Fourier transform infrared spectroscopy, potentiodynamic polarization measurements, hydrogen generation measurements, and electrochemical impedance spectroscopy. The amount of Mg–Al–CO3 layered double hydroxides (LDHs) in the film slightly decreased from the beginning of immersion to 120 h after immersion and gradually increased thereafter. Mg–Al–Cl LDHs were formed after 6 h of immersion and rapidly grew as the immersion progressed. In addition, even with the gradual decrease in the corrosion resistance of the film, there was no major damage observed on the substrates. These results indicate that the corrosion protection mechanism varied with the immersion time. The corrosion-resistant property under a short immersion time could be attributed to the high corrosion resistance of Mg(OH)2 and AlO(OH), whereas it is attributed to the coverage provided by the Mg–Al–Cl and Mg–Al–CO3 LDHs under a longer immersion duration.

The Influence of Pickling Treatment Parameters on the Surface State and Pre-Passivation Behavior of Super 13Cr Martensitic Stainless Steel

As a pre-treatment process in the pre-passivation of stainless steel, pickling treatment has a significant effect on the formation of the pre-passivation film. Thus, the surface composition and defects of Super 13Cr martensitic stainless steel (Super 13Cr) were evaluated under different pickling parameters to further improve the corrosion resistance of the pre-passivation film. The samples were prepared using the acid immersion method and by changing the immersion duration and the acid concentration. The inclusion and chemical composition on the Super 13Cr surface were characterized via a scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS). The pickling treatment contributes little to the morphology, dimension, and other characteristic parameters of the inclusions. With the increasing duration and acidification concentration, the Cr content on the surface of Super 13Cr increases initially and then decreases. By contrast, the Fe content decreases initially and then increases. The pickling parameters corresponding to the lowest Fe content and the highest Cr content are identical, i.e., the exposure duration is 50 s and the acid concentration is 48 g/L. The pickling treatment in this case could be divided into two stages: outer film dissolution and inner film dissolution. The pickling parameters basically contribute little to the defects of martensitic stainless steel but can significantly affect the surface Cr and Fe content. Retaining the Cr-enriched inner layer could improve the content of Cr in the pre-passivation film and then improve the corrosion resistance of the film. Thus, compared with the original sample with native film, the corrosion resistance of the sample with a Cr-enriched inner layer improved by a factor of about 40.

Effects of Si and Sn Contents and Heat-Treatment Temperature on the Corrosion Behavior of AISI 439 Ferrite Stainless Steel

This study was conducted to evaluate the corrosion resistance and optimize the heat-treatment process of AISI 439 ferrite stainless steel silicon and tin alloys with reduced chromium. The microstructure of the specimens and deposition under each condition were analyzed. The production of oxide films was compared based on the thickness of the film and the change in the contents of each element. In addition, electrochemical analyses of each heat-treatment condition was used to quantitatively compare corrosion resistance and passive film stability based on the relative chromium, silicon, and tin contents. It was found that the addition of silicon and tin compensated for the decrease in corrosion resistance induced by the chromium reduction. The addition of the two elements inhibited iron (Fe) oxide production in the surface oxide film, thereby improving the corrosion resistance of the material and improving the stability of the passive film. Moreover, the SiO2 and SnO2 layers inhibited the production of Fe oxide and contributed to the stability of the film along with Cr2O3, the main component of the passive film. However, when the heat treatment temperature increased above a specific temperature, the oxide inhibitory effect of the two elements was relatively offset. Nevertheless, further research to optimize the content of the three elements will help develop materials with superior mechanical properties and corrosion resistance.

Influence of Homogenization and Annealing Temperatures on the Microstructure, Mechanical Properties, and Passive Properties of Cold Rolled 2205 Duplex Stainless Steel

The effects of homogenization, cold working, and subsequent annealing treatment were studied on the microstructural evolution, mechanical properties, and passive properties of duplex stainless steel (DSS). A hot-rolled 2205 DSS was subjected to two processing routes. In one, the DSS goes through an extra homogenization step at 1100 °C for 1800 s before cold rolling. After cold deformation (~75%) the specimens were isothermally annealed at 900, 1000, and 1100 °C for 180 s. The microstructure evolution was studied by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XDR). Mechanical properties were evaluated by microhardness and tensile tests. The electrochemical behaviors were investigated by potentiodynamic measurements, electrochemical impedance spectroscopy (EIS) and Mott-Schottky analysis (MS). Chemical composition of the lowest corrosion resistant passive film was assessed by X-ray photoelectron spectroscopy (XPS). Homogenization before cold rolling lowered strain hardening, slowing the microstructural transformation process. The thermomechanical process did not change the semiconductor type of the passive films. However, grain refinement after annealing improved the corrosion resistance in borate buffer solution. Cold rolling significantly decreased the corrosion resistance. The passive film of the specimen homogenized before cold rolling had the lowest corrosion resistance and high amounts of Cr(OH)3 and FeO.

Analysis and Development Review of Metal and Metal/Ceramic Composite Coating Prepared on Magnesium Alloy Surface

Magnesium, as one of the lightest metal structural materials, also has its advantages such as high specific strength, good electromagnetic shielding characteristics, good processability and easy recycling, so it has a wide application prospect. However, its poor insulation, corrosion resistance, wear resistance and other properties limited it to be an alloy that can be used in a large area. Therefore, how to improve the corrosion resistance and wear resistance of magnesium alloy is the key to promote the development of magnesium alloy field. This paper reviews the research progress of using magnetron sputtering technology to prepare ceramic composite film on the surface of magnesium alloy and briefly introduces the film corrosion resistance and wear resistance of the thin films. It analyzes the impact of metal transition layer, process parameters and other factors on structure and properties of metal / ceramic coatings and prospects for the development prospects of magnetron sputtering in the field of magnesium alloy surface protection.

Magnetic properties and corrosion resistance of Co-DLC nanocomposite films with different cobalt contents

To realize the potential application of the Co-DLC magnetic nanocomposite film in biosensor, it is necessary to obtain superparamagnetic property with high magnetization and good corrosion resistance in Co-DLC film. However, the cobalt carbide produced in the traditional preparation process will deteriorate the superparamagnetic property of Co-DLC film. To suppress the formation of cobalt carbide, strong magnetic target co-sputtering has been induced to prepare the Co-DLC nanocomposite films in this work. The results show that the cobalt particles are distributed in the amorphous DLC matrix. Most of cobalt exists in the form of metallic cobalt, and no cobalt carbide is formed during the film deposition process. The films maintain superparamagnetic property, which fits well with the Langevin equation. The saturation magnetization of the Co-DLC films increases with the increase of cobalt content, which reaches 0.068 T at cobalt content of 36 at. %. Meanwhile, when the cobalt content increases, the degree of graphitization of the film increases, which leads to a decrease in corrosion resistance of the film. Whereas, the polarization resistance of Co-DLC nanocomposite film is still higher than 1.03 × 105 Ω·cm2. The Co-DLC nanocomposite films with cobalt content between 29 and 36 at. % exhibit superparamagnetic property with high saturation magnetization and corrosion resistance.

Thermal annealing effect on the corrosion resistance of AlCuNiTiZr high entropy alloy films in sulfuric acid solution

In this study, corrosion-resistant AlCuNiTiZr high-entropy alloy (HEA) films were deposited by direct current magnetron sputtering. The films were found to be amorphous. Corrosion resistance of the films in 0.5 M H2SO4 solution were investigated and compared with 316L stainless steel. The minimum corrosion current density of the HEA films was about one order of magnitude lower than that of 316L stainless steel. The inductively coupled plasma optical emission spectra showed that the concentrations of Cu, Ni, Ti and Zr ions in the corrosion solution were as low as 10−7 mol / L, while the concentration of Al ions was 7.5×10−6 mol / L. It is revealed that two passivation layers were formed on the surface from electrochemical impedance spectroscopy and equivalent electrical circuit, and the passivation layers resulted in protective effect on the AlCuNiTiZr HEA films in the sulfuric acid solution.

Evaluation of Corrosion Resistance of Thin Films Formed on AISI 316L Steel by Plasma Using Hastelloy as Cathodic Cage

Herein, the use of Hastelloy C‐276 as a cathodic cage for the deposition of thin films on the AISI 316L steel substrate by plasma is investigated. The films are processed through floating potential at 350, 375, 400, and 425 °C for 4 h, using a hydrogen–nitrogen mixture in the proportion of 40% and 60%, respectively. The thin films are investigated by X‐ray diffraction, scanning electron microscopy, Raman spectroscopy, and potentiodynamic polarization. The spectroscopy results point out the formation of different phases such as FeNi3, CrNi, and MoN1/2. Films acquired at 375 ºC present superior corrosion resistance with less negative corrosion potential (−0.020 V). The increase and decrease in FeNi3 and CrNi contents follow the improvement of the applied temperature, which is unbeneficial to the corrosion resistance of the films.

Corrosion Resistance and Oxide Film Structure of Stainless Steels and Ni-based Alloys under Sulfuric Decomposition Gas at High Temperature

Corrosion Resistance and Oxide Film Structure of Stainless Steels and Ni-based Alloys under Sulfuric Decomposition Gas at High Temperature