Coated Steel Surface Research Articles

Poly(o-anisidine) and poly(o-anisidine-co-aniline) polymers synthesized on the ZnFeNi alloy coated steel surface

Abstract ZnFeNi alloy was synthesized on the carbon steel surface in a sulfate bath using the galvanostatic method at a constant current of 1.5 mA for 300 seconds. Poly(o-anisidine) homopolymer and poly(o-anisidine-co-aniline) copolymer were synthesized on the ZnFeNi coated electrode surface. Poly(o-anisidine) homopolymer was synthesized in 0.05 M o-anisidine+0.2 M sodium oxalate medium, and poly(o-anisidine-co-aniline) copolymer was synthesized in 0.05 M o-anisidine+0.05 M aniline+0.2 M sodium oxalate medium. Electrochemical synthesis was carried out by cyclic voltammetry technique. The synthesized materials were characterized by electrochemical impedance spectroscopy, linear sweep voltammetry, open circuit potential-time and anodic polarization curves. Open circuit potential-time curves showed that polymer coatings had higher open circuit potential. By linear sweep voltammetry measurements, it was determined that ZnFeNi alloys were present at the base of the polymer layers after polymer synthesis. It was understood from the anodic polarization curves that the polymer coated electrodes had lower current values ​​than the uncoated ZnFeNi coated electrode, and the poly(o-anisidine) coated electrode had lower current values ​​than the poly(o-anisidine-co-aniline) coated electrode. From electrochemical impedance spectroscopy measurements, it was determined that the polarization resistance of polymer-coated electrodes was higher than the polymer-free electrode during long periods of waiting in 3.5% corrosive solution. Among the polymer-coated electrodes, it was understood that the homopolymer poly(o-anisidine) showed better corrosion performance than the poly(o-anisidine-co-aniline) copolymer.

Investigation Nano-coating for the Corrosion Protection of Petroleum storage tanks Steel

This work studies the protection from corrosion in the inner surface of petroleum storage tanks by applying nano-coating on the AISI1018 steel type used in these tanks. BNi-2 alloy, used as coating layer, was deposited using the DC sputtering technique to obtain protection layers of nano-coating. The cyclic potential dynamic polarization technique is used to study and evaluate the resistant metal to localize corrosion, for example, pitting and crevice corrosion. The samples were evaluated in a 3.5% NaCl aqueous solution using the polarization method to determine the corrosion rate. The input parameters of deposition included ion current 16 mA, vacuum 10-1 mbar, time of deposition was 60 minutes, and the distance between target and substrate was 2.5 cm. The surface roughness of the uncoated specimens was (0.1466 µm), and after coating, it decreased to (0.0933µm). The most important factor that affects the corrosion of the coated steel surface is the surface topography of steel before coating, as it is known that the spattering process coats the facing surface to target better than the inclined surface topography. Therefore, some micro scratches non-coated well worked as nucleation for corrosion as detected in stereo microscope images for coated and uncoated surfaces. By calculating the corrosion rate from cyclic potential dynamic polarization for coated and uncoated workpieces, pitting and crevice corrosion improved approximately ten times compared to the uncoated AISI1018 steel surface.

Joining of Co coated ferritic stainless steel to ceramic solid oxide cells by a novel Ag-SiO2 braze

• The wettability of Ag-SiO 2 braze on the YSZ and Co coated steel surface was studied. • Defect-free steel/YSZ joints was achieved and its microstructure was characterized in detail. • The Co-Si-O 2 phase diagram was calculated to explain the interfacial reaction. • A physical model was proposed to describe the interfacial microstructure evolution. A novel Ag-SiO 2 braze for Solid Oxide Cells was successfully developed and applied to join Co coated AISI 441 ferritic stainless steel to YSZ-NiO half cells. The braze showed an improved wettability on the coated steel and the YSZ compared to pure Ag. A defect-free steel/YSZ joint was obtained using an Ag-1SiO 2 braze jointed at 1000 °C for 30 min in air. The microstructure of the joints was characterized by scanning electron microscopy and transmission electron microscopy with energy-dispersive X-ray spectroscopy. Furthermore, a Co-Si-O 2 phase diagram was calculated and used to explain the experimental results and formulate a reaction mechanism. It was found, that during the air brazing process, Co 3 O 4 and (Co, Fe) 3 O 4 are formed by the oxidation of the prefabricated Co coating. The growth of Cr 2 O 3 was effectively impeded by the formed Co-based spinels. In a second step, Co 3 O 4 reacts with the SiO 2 present in braze. The Co 2 SiO 4 formed by the reaction ensures a firm bonding between the steel and Ag-SiO 2 braze.

Effect of reinforcement of mixed metal oxide nanoparticles in polyurethane resin for barrier and dynamic mechanical properties of steel structures

PurposeThis study aims to study the effect of the reinforcement of mixed CeO2-ZrO2 nanoparticles in the polyurethane (PU) for protection properties of steel structures.Design/methodology/approachElectrochemical techniques were used to study the anticorrosion properties of the generated PU/CeO2-ZrO2 nanocomposite coated steel. Dynamic mechanical testing was done to investigate the mechanical properties.FindingsIn natural seawater, Electrochemical impedance spectroscopy experiments indicated outstanding protective behaviour for the PU/CeO2-ZrO2-coated steel. The coating resistance of the PU/CeO2-ZrO2 nanocomposite coating was found to be roughly 30% greater than that of the PU coating. Scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction analyses of the coated steel surface revealed that the CeO2-ZrO2 was accumulated at the corrosion products, preventing the corrosion. Dynamic mechanical analysis revealed that when the nanoparticle concentration was 3 Wt.%, the PU/CeO2-ZrO2 nanocomposite coating had improved dynamic mechanical parameters.Originality/valueThe coating resistance of the PU/CeO2-ZrO2 nanocomposite was determined to be 2999.17 kΩ.cm2. The perceived current by scanning electrochemical microscopy analysis across the PU/CeO2-ZrO2 coating was 1.7 nA. The PU/CeO2-ZrO2 nanocomposite had a good hydrophobic behaviour (WCA: 101o). The newly synthesised PU/CeO2-ZrO2 composite offered great barrier and mechanical properties, preventing material degradation and increase the lifespan of the coated steel. Hence, this form of coating could be used as a viable coating material for industrial purposes.

Microfluidic water flow on laser-patterned MicroCoat® - coated steel surface

A series of hybrid textures with variable topography and chemical composition were obtained on a hydrophilic steel (AISI 304) substrate with a hydrophobic MicroCoat® coating at the increasing incident nanosecond laser fluence from 1.4 J/cm2 to 5.6 J/cm2. The microtopography of the textured surface was studied by laser microscopy and scanning electron microscopy (SEM), while the chemical composition of the surface was determined by IR spectroscopy. The contact angles of water wetting in the textured areas varied versus laser fluence from about 100° to 10°, which was explained by both ablative removal of the hydrophobic polymer coating and the increase in roughness of the hydrophilic steel surface. The time dependence of the contact angle on the different textures, which demonstrated hydrophobization at different time scales depending on the texturing conditions, was analyzed. Autonomous directional flow was observed on laser-patterned wetting-gradient structures of various shapes, and the flow velocity of water droplets on these structures were measured. It was shown that the velocity of water drop spreading on the gradient structures depends on the difference in contact angles on adjacent spots. The various modules fabricated can be harnessed in chemical and biomedical microfluidic devices.

Investigation Effect of Zinc Nanoparticles on The Mechanical and Anticorrosion Properties of Epoxy Coatings on Stainless Steel Surface

In this study, effects of zinc nanoparticles (ZNPs) on the mechanical properties of epoxy coatings and anticorrosion behavior on the stainless steel were investigated. The nanocomposites (NCs) were obtained by adding ZNPs (0.5, 1.0, 1.5 wt%) to epoxy resin. The first stage in this study, bulk samples were prepared for tensile test and DSC, TGA, FTIR, SEM analysis. The test and analysis were performed separately for samples cured at room temperature for 24 h and postcured at 80 °C for 15 h in the oven. The results indicated that both postcuring and adding ZNPs caused an increase in the mechanical properties of the epoxy matrix. Tensile strength increased by 13.2% and 90.2% in the postcured NC (1.0% Zn) and untreated NC (0.5% Zn) respectively. The NCs prepared with the same parameters for the second stage were coated on AISI 304 test panels and the panels were postcured in the oven. The anticorrosive performance of the coatings was studied by an immersion test. According to the corrosion test results, it was observed that the coated steel surface preserves the best rate of 1.0% ZNPs containing epoxy composite. In addition, impact resistance, flexibilities and adhesion properties of the coating were analyzed.

Oxidation behavior of ferritic stainless steel interconnect coated by a simple diffusion bonded cobalt protective layer for solid oxide fuel cells

A protective cobalt coating is fabricated on AISI 441 ferritic stainless steel interconnect by diffusion bonding method for solid oxide fuel cells. Oxidation behavior of coated and bare steels are studied. Microstructure evolution of steels during oxidation is analyzed by XRD, SEM and TEM with EDS. After 800 °C/1000 h oxidation, three layers are observed on the coated steel surface: a Co3O4 top layer, a (Co,Fe)3O4 middle layer and a Cr2O3 inner layer. The thickness of Cr2O3 of the coated steel is 2.7 μm, while that of bare steel is 10.3 μm. The out-migration of Cr is effectively suppressed.

Dynamic Contact Angle and Corrosion Test Measurements on Cu and CuO-Stearic Acid Modifications on Steel Surfaces

In this study, a copper (Cu) coated steel surface’s dynamic con-tact angle and corrosion rate was compared to the bare steel and stearic acid modified surfaces. Various steps of surface treatment have been performed including electrodeposition of Cu, CuO formation from H2O2 immersion with stearic acid modi-fication to obtain dynamic contact angle and the corrosion rate data. The Cu-coated steel’s dynamic contact angle was increased as it implied the surface after Cu treatment was more hydro-philic than the bare steel, with sliding angle and contact angle hysteresis of 54.9o ± 2.39o and 39.5o ± 1.91o, respectively. How-ever, corrosion test measurements by using a mass loss method to quantify the corrosion rate showed that Cu-coated steel and stearic acid-modified Cu-O coated steel had no remarkable dif-ference in corrosion rate. It was found that the Cu-coated steel and stearic acid-modified Cu-O coated steel had corrosion rate eight times slower than the bare surface.

Development of polyurethane-based superhydrophobic coatings on steel surfaces.

In this study, a superhydrophobic coating on steel surface has been developed with polyurethane, SiO2 nanoparticles and hexadecyltrimethoxysilane by using a spin-coating technique. Characterization of the coated steel surface was done by using the contact angle measurement technique, scanning electron microscopy and Fourier transform infrared spectroscopy. With a water tilt angle of 4° ± 2° and static contact angle of 165° ± 5°, the coated surface shows a superhydrophobic and self-cleaning nature. Chemical, thermal, mechanical stability tests and droplet dynamic studies were done to evaluate performance of the coating. Excellent self-cleaning, anti-fogging and anti-corrosion properties of coated steel surfaces make them ideal for industrial applications. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 3)'.

Electroless NiP-TiO2 sol-RGO: A smart coating for enhanced corrosion resistance and conductivity of steel

Nickel phosphorus – titanium dioxide sol – reduced graphene oxide (NiP-TiO2 sol-RGO) coating was firstly prepared by using a simple one-pot electroless plating to effectively improve both corrosion resistance and conductivity of steel. Initially, titanium dioxide sol (TiO2 sol) was synthesized via sol-gel method and then used to intercalate between graphene oxide (GO) nanosheets for increased GO dispersion and loading prior to electroless deposition. The parameters controlling the coating appearance and property, (e.g. amount of TiO2 sol, electroless plating time and amount of GO) were systematically optimized. The as prepared NiP-TiO2 sol-RGO and the coated steel surface morphologies were characterized by transmission electron microscopy and scanning electron microscopy. The hydrophobicity, corrosion resistance and conductivity of the coated steel were examined by contact angle measurement, electrochemical testing and four-point probe conductivity measurement, respectively. NiP-TiO2 sol-RGO coated steels show high homogeneity coating with ultra-thin water-repellent RGO layer fully covering on the outer surface leading to significant improved corrosion resistance and electrical conductivity of steel. These promising properties of the coating might be very useful for electronic part applications, which requires both high corrosion resistance and high conductivity with less sensitive to humidity, such as electronic parts and electrode for electrochemical sensors.

Effect of Cu2O thin film on Cu–Sn alloy coated steel surface in promoting interfacial adhesion with rubber

In the present study, effect of Cu2O film deposited via successive ionic layer adsorption and corresponding chemical reaction (SILAR method) on Cu–Sn coated steel substrate was explored for the purpose of improving the adhesion of steel with rubber. The effect of the relative alkali concentration in the oxide film deposition bath and the number of immersion cycles on the interfacial adhesion affecting the nature of oxide film deposited, its thickness and surface coverage were investigated. In the current study, Cu–Sn coated steel bead wire with coated surface roughness (Ra) around 2 μm showed an improvement of 33% in adhesion (in terms of pull out force) with an optimum alkali/Cu ion concentration of 25:1 with single dipping cycle attributed to an optimum oxide coating thickness of ~70 nm. Surface morphology study exhibited formation of thicker coating with increase in number of dipping cycles. Satisfactory thermal stability of the Cu2O film was confirmed as no re-oxidation of the Cu2O film to CuO was observed in the 200 °C heat treated samples.

Graphene integrated polyaniline nanostructured composite coating for protecting steels from corrosion: Synthesis, characterization, and protection mechanism of the coating material in acidic environment

We report on the synthesis, characterization and application of highly crystalline graphene integrated polyaniline nanostructured composites as corrosion protection coatings. The coated surface showed a decline in corrosion current up to ∼3–4 orders of magnitude in 0.1M HCl. Composite coating with 1.92wt.% graphene loading showed best protection. SEM images obtained after the corrosion tests reveal several pits on the coated steel surface with network like structures. A plausible mechanism of the corrosion protection mechanism of the composite coating has been proposed to explain the fate of the material in acidic environment.

Measuring Adhesion Forces in Powder Collectives by Inertial Detachment

One way of measuring adhesion forces in fine powders is to place the particles on a surface, retract the surface with a high acceleration, and observe their detachment due to their inertia. To induce detachment of micrometer-sized particles, an acceleration in the order of 500,000g is required. We developed a device in which such high acceleration is provided by a Hopkinson bar and measured via laser vibrometry. Using a Hopkinson bar, the fundamental limit of mechanically possible accelerations is reached, since higher values cause material failure. Particle detachment is detected by optical video microscopy. With subsequent automated data evaluation a statistical distribution of adhesion forces is obtained. To validate the method, adhesion forces for ensembles of single polystyrene and silica particles on a polystyrene coated steel surface were measured under ambient conditions. We were able to investigate more than 150 individual particles in one experiment and obtained adhesion values of particles in a diameter range of 3-13 μm. Measured adhesion forces of small particles agreed with values from colloidal probe measurements and theoretical predictions. However, we observe a stronger increase of adhesion for particles with a diameter larger than roughly 7-10 μm. We suggest that this discrepancy is caused by surface roughness and heterogeneity. Large particles adjust and find a stable position on the surface due to their inertia while small particles tend to remain at the position of first contact. The new device will be applicable to study a broad variety of different particle-surface combinations on a routine basis, including strongly cohesive powders like pharmaceutical drugs for treatment of lung diseases.

Tribological properties of laser textured and DLC coated surfaces with solid lubricants

Hydrogen free diamond-like carbon coatings (DLC), i.e. tetrahedral amorphous carbon (ta-C) films, have high hardness and low coefficient of friction at ambient temperature and humid conditions. However, the coefficient of friction and wear rate in sliding contacts against steel surfaces increase severely at elevated temperatures. Adding solid lubricant into microreservoirs produced by Laser Surface Texturing (LST) has been reported to decrease the coefficient of friction of sliding surfaces. In this study, incorporation of MoS2 and WS2 solid lubricants onto laser textured and ta-C coated steel surface by burnishing was demonstrated to provide improved tribological properties such as low friction and high wear resistance at elevated temperature with an extended lifetime of the surfaces.

Coated Steel Surfaces with WC by Lasers Action

In this work low carbon steel samples were coated by tungsten carbide (WC), and then the properties of the obtained coatings were evaluated, such as morphology, hardness, phase composition and dimension of the layer. The results indicate the formation of a new phase, composed of iron carbide in the base metal, a more dense coating has been obtained when the WC powder was sprayed directly on to the steel and then irradiated with the laser beam.

Laser treatment of carbon film coated steel surface

Laser controlled melting in nitrogen of a preprepared steel surface has been carried out. A carbon film formed from a phenolic resin precursor containing 5 vol.-% of TiC particles was first formed at the surface of the steel before the laser treatment. The morphological and metallurgical changes in the laser treated region were examined using scanning electron microscopy and X-ray diffraction (XRD). Temperature and stress fields were predicted in the workpiece using a finite element code. The residual stress at the surface was measured using XRD. The hardness of the workpiece was measured using microindention testing. It was found that the laser treatment results in a dense layer composed of fine grains and TiC particles at the surface, which enhances surface microhardness. The presence of the carbon film at the surface and high pressure nitrogen gas enable the formation of FeN3 and Fe(N,C) phases at the surface and nitrogen diffusion into the substrate material causes nitride precipitation below the surface. The residual stress measured using the XRD technique at the surface region is −420 MPa, which is in agreement with the numerical predictions.

Influence of natural inhibitor, pigment and extender on corrosion of polymer coated steel

Lupine (Lupinous albus L.) seeds extract was incorporated into a vinyl chloride–vinyl acetate copolymer based paint formulation to control steel corrosion in 0.5M NaCl. Evaluation of this system included the use of electrochemical impedance spectroscopy (EIS) and a salt spray cabinet for accelerated aging tests. The EIS data demonstrated that highest protection was attained at a lupine threshold concentration of 0.025g/L. Two white color pigments (ZnO and TiO2) and three extenders (CaCO3, mica and talc) were tested as paint additives. The accelerated aging tests showed that the coated steel panels containing TiO2 had a high degree of blistering while those containing ZnO exhibited reasonable hiding power and better protection efficiency. Field tests indicated that the presence of TiO2 enhanced the growth of fouling organisms over the coated steel surface.

Corrosion protection of stainless steel by polysiloxane hybrid coatings prepared using the sol–gel process

Polysiloxane hybrid films were deposited on 316 L stainless steel substrates by dip-coating in a sol prepared by acid-catalyzed hydrolytic co-polycondensation of tetraethoxysilane (TEOS) and 3-methacryloxy propyltrimethoxysilane (MPTS), followed by radical polymerization of methacrylic moieties. Structural features of the polysiloxane hybrids were studied using 13C and 29Si nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), as a function of the TEOS/MPTS ratio, which ranged between 0 and 2. The efficiency of corrosion protection of hybrid-coated stainless steel was investigated by X-ray photoelectron spectroscopy (XPS), potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) after immersion of the material in acidic and neutral saline aqueous solutions. The NMR and TGA results indicated a high degree of polymerization and polycondensation (85%) for the hybrid film with a TEOS/MPTS ratio of 2, as well as elevated thermal stability of 410 °C and excellent adhesion. The XPS analysis confirmed the hybridized structure of the polysiloxane network, and showed that no corrosion-induced changes had occurred on the coated steel surface after 3 weeks of immersion in 3.5% NaCl solution. Potentiodynamic polarization curves showed that the hybrid coating prepared using a TEOS/MPTS ratio of 2 yielded the best anti-corrosion performance. It acts as an efficient physical barrier, increasing the total impedance and reducing the current densities by 2 orders of magnitude, compared to the bare electrode. The impedance results obtained for the two electrolytes were discussed based on the electrical equivalent circuits used to fit the experimental data.

One-Step Potentiostatic Electrodeposition of Polypyrrole Coatings on Zinc Coated Steel Surfaces

In this paper the elaboration and characterization of polypyrrole coatings on active metallic surfaces were performed. The one-step electropolymerization of pyrrole on zinc-coated steel electrodes was investigated under several techniques (cyclic voltammetry, electrochemical impedance spectroscopy, atomic force microscopy) in aqueous medium. Adherent and homogeneous PPy coatings were obtained using tartrate counter-ions. The obtained results show that the PPy coatings increase the corrosion potential and reduce the corrosion current.

The effects of immersion time on morphology and electrochemical properties of the Cr(III)-based conversion coatings on zinc coated steel surface

The main purpose of this paper is to develop a dynamic and non-destructive method to quantify and correlate the microstructure changes of the Cr(III) layer by electrochemical techniques. The open circuit potential (OCP) analysis reveals the nucleation growth mechanisms of the Cr(III) layer and the dissolution phenomena of Zn. In addition, the effects of immersion time to the corrosion behavior of Cr(III)-based conversion coatings (TCCCs) on electrogalvanized steel were studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in a 3.5% NaCl solution. Furthermore, surface morphology of the Cr(III) coatings under different immersion times was examined using both a scanning electron microscope and an atomic force microscope. From the potentiodynamic polarization experiment, the corrosion current density ( I corr) of the specimen with immersion time of 60 s was found appreciably small, representing the inheritance of the best anticorrosion performance. Additionally, the corrosion resistance of the Cr(III)-coating for the specimens obtained between 30 s and 60 s is two order higher than those of the untreated specimen from the EIS experiments. Results show that the quality of Cr(III)-based conversion coatings was strongly influenced by the immersion time of Cr(III) solution. And the optimal immersion time is recommended in the range of 30–60 s.