Corrosion Resistance Of Coatings Research Articles

Air-based sputtering deposition of TiN(O)/a-TiNxOy multilayer films for enhanced mechanical properties and corrosion resistance

Extensive research has explored multilayer films for their distinctive mechanical and functional properties. This study employs an air-based sputtering technique, using air as a reactive gas under low vacuum conditions, to produce TiN(O)/a-TiNxOy multilayer films. By alternately adjusting the air/Ar flow ratios, the multilayer films with various modulation periods were created. The crystalline TiN(O)/amorphous TiNxOy multilayered structure was confirmed via cross-sectional microscopy and electron energy loss spectroscopy images and mappings. Hardness (H) and elastic modulus (E) initially increased, peaked, and then decreased with the modulation period, reaching a maximum hardness of 31.2 GPa and an elastic modulus of 343 GPa. The enhancements may be attributed to internal compressive stress, interface strain effects, and the inhibition of dislocation propagation throughout the films. Higher H/E ratios (0.09–0.11) and H3/E2 ratios (0.23–0.28 GPa) suggest enhanced resistance to elastic and plastic deformation, surpassing those of single-layered TiN(O). This enhancement is primarily attributed to the hard/soft multilayer design. Potentiodynamic polarization tests revealed improved corrosion resistance with decreasing modulation period, reaching optimal values Ecorr at −0.089 V and Icorr at 0.272 μA/cm2. This improvement is mainly ascribed to the multilayer design, which inhibits direct corrosion through grain boundaries. This air-based sputtering technique offers a facile approach for producing complex multilayer films, promising enhanced mechanical properties and corrosion resistance of coatings for various applications.

Development and electrochemical investigations of enhanced corrosion-resistant Polyvinylcarbazole-TiO2 hybrid nanocomposite coatings on 316L SS for marine applications

The present study focuses on evaluating the corrosion resistance of 316L stainless steel substrates with Polyvinylcarbazole (PVK)/TiO2 hybrid nanocomposite coatings (HNC). Using the chronoamperometry approach, the HNC were electrochemically synthesized on 316L stainless steel substrates, incorporating various weight (%) 1 %, 2 %, 3 % of TiO2 nanoparticles into the PVK matrix. The findings of the surface morphology investigation verified that the 316L SS had a dense and smooth PVK/TiO2 coating. A low surface roughness and high contact value of the PVK/TiO2 coatings are also responsible for the decrease in corrosion rate of the 316L SS. The corrosion protection efficiency of the PVK/TiO2 HNC were investigated through open circuit potential (OCP) measurement, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) analysis in 3.5 wt% NaCl solution. The corrosion rate obtained from the polarization studies of the HNC coatings as follows PVKT-2 < PVKT-3 < PVKT-1 < PVK < 316L SS. Results revealed that an optimal loading of 2 wt% TiO2 nanoparticles significantly enhanced the corrosion resistance of the coating. The enhanced electrochemical impedance response for PVK/TiO2 coatings was verified by EIS experiments. The study demonstrates that the incorporation of TiO2 nanoparticles into the PVK matrix effectively creates a barrier layer at the coating-metal interface, inhibiting the entry of aggressive ions. Microhardness studies revealed the increase in hardness value of the PVK and PVK/TiO2 coatings indicated the protective nature of the coating and provided high mechanical strength to 316L SS. The tape adhesion tests carried out on the coated specimens also indicated a good adhesion of the PVK/TiO2 on the 316L SS surface.

Fabrication Aspects and Performance Characterization of α-Al2O3/AlPO4 Based Sandwich Configuration Flow Channel Inserts and Coatings for High Temperature Liquid Metal Applications

Abstract Liquid metals (LMs) exhibit several key characteristics justifying their utilization as coolants and breeders for nuclear fusion reactors and advanced fission reactors. In fusion reactors, the LMs confront an exorbitantly high flow retarding force, due to the magneto-hydro-dynamics (MHD) effect, imposing significant demands on the pumping power and designs of ancillary coolant systems. Corrosion of structural materials leading to activated corrosion products and coolant chemistry control are some of the vital issues common to both fusion and fission reactors employing liquid lead (Pb) and its alloys. To address these concerns, different technological solutions such as flow channel inserts (FCIs) and high temperature compatible corrosion resistant coatings are being investigated to provide a chemical and/or electrical isolation between the LM and structural material for advanced reactors. In this study, three different prototype geometries (circular, square, and 90 deg bend) of steel-insulator-steel sandwich FCIs are fabricated for fusion reactor applications and an extensive characterization of the electrical insulation is performed over an operating temperature range of 100 °C–600 °C. Welding trials and pneumatic pressure tests up to 10 kg/cm2 (g) are performed on the assemblies to validate the electrical and mechanical integrity over typical fusion reactor operational regime. This paper presents detailed fabrication aspects along with quantitative estimations of insulation filling density, electrical insulation performance and, for the first time, a detailed systematic study of insulation degradation resulting from the combined effects of tungsten inert gas (TIG) welding, exposure to pressure and machining operations on these FCIs. The paper also provides critical details derived from the metallurgical examinations and visual observations from the destructive tests executed on the prototypes. Further, from an implementation perspective toward Lead-cooled Fast Reactors (LFRs), a preliminary feasibility assessment of the α-Al2O3/AlPO4 coating is performed through thin film deposition trials on planar and non-planar substrates followed by mechanical characterizations, such as coating thickness, surface roughness, adhesion strength and microhardness. Metallurgical analyses are presented and discussed to assess Pb ingress after 700 h of continuous exposure to molten Pb alloy at 300 °C–400 °C.

Effect of ultrasound assistance on the mechanical performance and corrosion resistance of Zn-Ni coatings produced by cathode plasma electrolysis deposition

Zn-Ni coatings were fabricated via ultrasonic-assisted cathodic plasma electrolysis deposition (US-CPED) technology. The results demonstrate that ultrasonic assistance can significantly affect the deposition and growth process of Zn-Ni coatings, which is attributed to ultrasonic vibration reducing the diameter of bubbles and inducing a more uniform distribution of the vapor gaseous envelope (VGE) on the surface of the substrate. The Zn-Ni coatings with more homogeneous microstructure were formed due to the more uniform plasma discharge process on the surface of the substrate based on the VGE uniform distribution. Compared to the Zn-Ni coatings without ultrasonic assistance, the thickness and roughness of Zn-Ni coatings with ultrasonic assistance increased by >80 % and decreased by over 40 %, respectively. Better Zn-Ni coating quality brings higher corrosion resistance. In addition, ultrasound can accelerate the iteration of bubbles in VGE to enhance the work-hardening effect, improving the mechanical properties of the Zn-Ni coatings. This work introduces a novel insight into the controllability of the CPED process and paves the way for exploring other methods to stabilize the CPED process.

Amino-Modified Graphene Oxide from Kish Graphite for Enhancing Corrosion Resistance of Waterborne Epoxy Coatings.

Waterborne epoxy (WEP) coatings with enhanced corrosion resistance were prepared using graphene oxide (GO) that was obtained from kish graphite, and amino-functionalized graphene oxide (AGO) was modified by 2-aminomalonamide. The structural characteristics of the GO and AGO were analyzed using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). And the anti-corrosive performance of waterborne epoxy-cased composite coatings with different addition amounts of AGO was investigated using electrochemical measurements, pull-off adhesion tests, and salt spray tests. The results indicate that AGO15/WEP with 0.15 wt.% of AGO has the best anti-corrosive performance, and the lowest frequency impedance modulus increased from 1.03 × 108 to 1.63 × 1010 ohm·cm-2 compared to that of WEP. Furthermore, AGO15/WEP also demonstrates the minimal corrosion products or bubbles in the salt spray test for 200 h, affirming its exceptional long-term corrosion protection capability.

Anti-corrosion resistance of coatings based on powder epoxy paints containing modifiers

The corrosion resistance of coatings (thickness 70 µm) based on epoxy powder paints modified with aliphatic amine or a mixture of anticorrosive pigments to the action of sodium chloride solution and salt spray has been studied. It is showed that with the increase of molecuar weight of initial epoxy oligomer and also at the incorporation of chemisorbing alifatic amine, containing polar groups, to the decrease in the permeability of the sodium chloride solution into the coating material is observed. It has been established that the observed changes in the properties of the coatings are due to the formation of a spatial structure of the polymer with different cross-link frequencies. It is shown that the introduction of a mixture of anti-corrosion pigments into the composition of paints provides a significant increase in the protective properties of coatings and a high preservation of the physical and mechanical properties of coatings in comparison with the base compositions. For 9000 hours of testing in a sodium chloride solution, the strength characteristics of the coatings decrease by about 10–12 % from the original ones. Based on the results of tests of coatings to the action of salt spray, the possibility of using the developed epoxy powder paints for operation in environments of a high atmospheric-corrosive category – C 5–1, including the application of coatings directly on a metal surface (Direct to metal) without multi-stage preparation of the metal surface for painting, is shown.

Effect of TiC nanoparticles on microstructure and corrosion resistance of laser cladding Al-CNTs composite coatings on AZ31 alloy

ABSTRACT Al-CNTs composite coatings were successfully prepared on AZ31 alloy using laser cladding (LC). The effect of TiC nanoparticles on microstructure and corrosion resistance of the LC Al-CNTs and Al-TiC-CNTs composite coatings were investigated. The LC composite coatings were composed of α-Mg solid solution phase and β-Al12Mg17, Mg2Al3, Mg32(Al,Zn)49 and TiC compound phases. A sound metallurgical bonding interface was produced between the LC composite coatings and AZ31 alloy. The surface microhardness and corrosion resistance of the LC composite coatings, which were gradually decreased with increasing the content of carbon nanotubes (CNTs) and TiC nanoparticles, were significantly enhanced compared to those of the AZ31 alloy. The LC Al-CNTs (99 wt% Al + 1 wt% CNTs) composite coating exhibits excellent surface microhardness and corrosion resistance. The mean surface microhardness, self-corrosion potential and self-corrosion current were 266.4 HV, −1.233 V and 2.55 × 10−5 A, which were 426.2%, 78.9% and 16.5% of the AZ31 alloy, respectively.

Heterogeneous nucleation induced A. pernyi/B. mori silk fibroin coatings on AZ31 biometals with enhanced corrosion resistance, adhesion and biocompatibility

Silk fibroin coatings on biomedical magnesium alloys have garnered significant attention due to their enhanced corrosion resistance and biocompatibility. However, the utilization of wild A. pernyi silk fibroin, known for its RGD sequence that facilitates tissue regeneration, presents a challenge for corrosion-resistant coatings on magnesium alloys due to its weak adhesion and high dissolution rate. In this study, we employed hexafluoroisopropanol as a solvent to blend A. pernyi silk fibroin with B. mori silk fibroin. The resulting blended fibroin coating at a 3:7 mass ratio exhibited a heterogeneous nucleation effect, enhancing β-sheet content (32.3 %) and crystallinity (28.6 %). This improved β-sheet promoted the “labyrinth effect” with an Icorr of 2.15 × 10−6 A cm−2, resulting in significantly improved corrosion resistance, which is two orders of magnitude lower than that of pure magnesium alloy. Meanwhile, the increased content of exposed serine in zigzag β-sheet contributes to a higher adhesion strength. Cell cytotoxicity evaluation confirmed the enhanced cell adhesion and bioactivity. This work provides a facile approach for wild A. pernyi silk fibroin coatings on magnesium alloys with enhanced corrosion resistance, adhesion and biocompatibility.

Influences of flame remelting and WC-Co addition on microstructure, mechanical properties and corrosion behavior of NiCrBSi coatings manufactured via HVOF process

We investigated the microstructures, mechanical properties, and corrosion behavior of NiCrBSi coatings upon the addition of the WC-Co powder in various amounts (0, 5, 10, 15, and 20 wt%) using the high velocity oxy-fuel process on low-carbon steel. Additionally, flame remelting was performed at 1100 °C for 1 min following thermal spraying of the coatings. The microstructures of the coatings were examined using X-ray diffractometry and scanning electron microscopy, and the mechanical properties of the coatings were assessed via Vickers microhardness and ball-on-disk tests. The corrosion behavior of the coatings was evaluated using potentiodynamic polarization testing in a 20 vol.% sulfuric acid solution. The results demonstrated that an increase in the WC-Co amount enhanced the hardness and wear resistance of the coatings. For 10–20 wt% WC-Co addition, small cracks were observed in the as-sprayed coatings owing to the heat applied during thermal spraying and rapid cooling, respectively. The presence of porosity directly affects the corrosion behavior of the coatings. Flame remelting led to better cohesion and the distribution of the γ-Ni and WC phases, reducing microdefects, such as pores and cracks. The mechanical properties of the coatings improved as the WC-Co amount increased after flame remelting, resulting in the formation of intermetallic compounds (FeB, CoSi2, and Ni2Si) along with the WC phase. The flame-remelted NiCrBSi/ 10 wt% WC-Co coating demonstrated high hardness and low wear and corrosion rates (1072.26 HV, 4.8 × 10−6 mm3/m, and 0.560 mm/year, respectively). Therefore, WC-Co addition and the flame remelting process significantly enhanced the properties of NiCrBSi coatings. This study highlights the substantial contributions of WC-Co addition and the flame remelting process in enhancing the mechanical properties and corrosion resistance of NiCrBSi coatings. These findings offer valuable insights for optimizing the performance of commercially available coatings in various real-world applications in maintaining power plants and industrial components like high-pressure pump piston rods, acid-resistant pumps in oil refineries.

Corrosion behavior and incorporation mechanism of Y2O3-TiO2 composite coatings fabricated on TC4 titanium alloy by plasma electrolytic oxidation

The anti-corrosion of titanium alloys is a topic of concern in many fields. In our work, the Y2O3-TiO2 composite coatings were fabricated on the TC4 titanium alloy by plasma electrolytic oxidation (PEO). The reaction was conducted in an electrolyte system made up of Na2SiO3, KOH, and (NaPO3)6. The effects of additive Y(NO3)3 in the electrolyte on the microstructure, chemical component, phase structure, thickness, hydrophobicity, and corrosion resistance of the composite coatings were studied. The results show that the composite coatings prepared by PEO reaction exhibit preferable corrosion resistance. The addition of Y(NO3)3 is beneficial for thickening the coatings, reducing their porosity and pore size, and further improving their hydrophobicity and corrosion resistance. Furthermore, the incorporation mechanism of Y2O3 was discussed based on thermodynamics theory.

Effect of Al content on the microstructure, mechanical property and lead-bismuth eutectic corrosion resistance of refractory AlxTiNbZrMoV coatings produced by magnetron sputtering

In present study, refractory AlxTiNbZrMoV (x=0.2, 0.5, 0.9 and 1.2 in molar ratio) high-entropy alloy coatings were prepared by magnetron sputtering technology. The microstructure, mechanical property and lead-bismuth eutectic corrosion resistance of the AlxRHEA coatings were investigated. With the increase of Al content, the coatings maintained the amorphous structure, and no intermediate phase was generated. The hardness and elastic modulus of the AlxRHEA coatings were higher than that of Al-free coating. After the LBE corrosion, formation of surface Fe-oxide layer occurred in the four AlxRHEA coatings. The Al0.5RHEA and Al0.9RHEA coatings exhibited improved corrosion resistance. The results indicate that for HEA, the formation of protective alumina layer can be on the basis of Al enrichment on the coating surface to continue to improve the oxidation resistance.

Advancements in Multilayer Coatings on Aluminium Alloy-Based Bipolar Plates for PEMFC Application

Fuel cells represent a revolutionary and sustainable approach to energy conversion, offering a clean alternative to traditional combustion-based power generation. These electrochemical devices convert the chemical energy of a fuel, typically hydrogen, directly into electricity. The fundamental working principle involves the electrochemical reaction between hydrogen and oxygen, facilitated by a catalyst, to produce electricity, water, and heat as byproducts in Proton Exchange Membrane (PEMFC). This strategic use of aluminum (Al) alloy for Bipolar plates (Bp) aligns with the industry's commitment to advancing materials and design methodologies, ultimately promoting the optimization of fuel cell technology in terms of performance, durability, and economic feasibility. This comprehensive review investigates recent progress in the development of multilayer coatings tailored for Al alloy-Bp in PEMFCs. Al alloys are a preferred substrate material due to their cost-effectiveness, lightweight nature, and high thermal conductivity. However, challenges such as corrosion, electrical conductivity, and interfacial contact resistance have spurred extensive research into innovative coating solutions. The review critically examines various coating materials, deposition techniques, and performance evaluation methods aimed at addressing the challenges associated with al alloy Bp. Special emphasis is placed on corrosion-resistant coatings, conductive layers, and interfacial modifiers. The assessment encompasses both established technologies and cutting-edge approaches, including nanocomposite coatings, self-healing materials, and advanced characterization methods. By synthesizing and analyzing existing literature, this review provides a comprehensive overview for researchers, engineers, and policymakers involved in advancing PEMFC technology. The findings underscore the crucial role of multilayer coatings in augmenting the performance and longevity of al alloy-based Bp, offering valuable insights to guide further research and development in the pursuit of efficient and durable fuel cell systems. In comparing the aluminum grades Al-356, Al-5052, Al-6061, and Al-7075, it is observed that Al 5052 exhibits lower corrosion density, providing greater efficiency compared to other aluminum grades. In the case of Al 356, the potentiostatic result yields a lower value than that of other aluminum grades. Consequently, these findings suggest a tendency for favorable corrosion resistance and electrodeposition in both Al 5052 and Al 356, making them noteworthy choices in applications requiring these particular material characteristics.

Fabrication and characterization of Ni-Co-TiN/ CeO2 composite coating by ultrasonic vibration-assisted jet electrodeposition

A novel method was proposed for the fabrication of Ni-Co-TiN/ CeO2 composite coatings as protective coating by ultrasonic vibration-assisted jet electrodeposition (UVAJE). The mechanism of ultrasonic vibration on the preparation of composite coatings by jet electrodeposition is analyzed. The influences of mixed particle (micron-TiN/nano-CeO2) concentration and ultrasonic vibration on the surface morphology, phase structure, microhardness, adhesion properties, wear resistance and corrosion resistance of coatings were investigated. Coating samples were prepared by traditional jet electrodeposition (TJE), comparison with UVAJE. It was found that the mixed particles improved the performance of the coating, the ultrasonic vibration improved the surface morphology, mechanical properties and corrosion resistance of the coating compared to TJE. The coating by UVAJE had the highest microhardness, the best wear resistance and the best corrosion resistance when the concentration of mixed particles was 4 g/L. TiN/ CeO2-enhanced Ni-Co co-deposition prepared under optimal parameters opens up new avenues for replacing hard chromium, with potential applications in the defence industry, power electronics.

Microstructure and performance optimization of laser cladding nano-TiC modified nickel-based alloy coatings

In this study, different alloy powders containing nano-sized TiC were prepared using a combination of mixed ball milling adsorption, electroless Ni-P-TiC, and Ni-B-TiC plating techniques. The effects of different nano-TiC addition methods on the microstructure, wear resistance, and corrosion resistance of laser-coated nickel-based self-fusing alloy coatings were comprehensively studied. The effects of the nano-TiC method on the microstructure, wear resistance, and corrosion resistance of laser-coated nickel-based self-fusing alloy coatings were comprehensively studied. The results show that agglomerated TiC particles appeared in the coatings prepared with ball-milled powder. In contrast, the coatings produced by introducing nano-sized TiC through the chemical plating methods exhibited a uniform distribution of the TiC phase. The coatings prepared with Ni-B-TiC plating powder showed a bimodal microstructure and most of the TiC particles are distributed at grain boundaries, which hinders grain growth and refines the microstructure of the coating. The corrosion resistance of the Ni2 coating prepared with ball milling adsorbed nano TiC powder shows the best corrosion resistance. The wear resistance of the Ni4 coating prepared with the Ni-B-TiC plating powder was significantly better than that of the other samples. This study provides an effective way to improve the wear or corrosion resistance of laser cladding nickel-based self-fluxable alloy coatings.

In situ electrochemical deposition enables dense polypyrrole grown on AZ31 surface for improving corrosion resistance

This study addresses the poor corrosion resistance of Mg alloy. Based on an in-situ electrochemical strategy, poly(pyrrole) coatings were selectively prepared on the surface of Mg alloys with controlled thickness using constant current and cyclic voltammetry techniques. The results indicate that PPy-CV coatings possess greater thickness and a denser structure. Combining studies on corrosion behaviors such as electrochemical analysis, and immersion, it was found that the coatings effectively prevent solution intrusion, thereby enhancing the alloy's resistance to corrosion. And also provides a new avenue for designing corrosion-resistant coatings, particularly for conductive materials such as polyaniline, poly(3,4-ethylenedioxythiophene), etc.

The effects of synthesis route and LaB6-doping on FeCoNiCrTi coating performance: Morphology, microstructure, microhardness and corrosion resistance

In this work, the FeCoNiCrTi HEA coatings were fabricated on the Ti6Al4V surface via laser cladding technology. The effects of synthesis routes (different energy density, Led) and LaB6-doping on the single-track morphology, phase distribution, microstructure, microhardness and corrosion resistance of HEA coatings were comprehensively studied. Interestingly, the regulation of Led and addition of LaB6 significantly reduced the crack sensitivity and dilution rate of the coating. On the one hand, the optimized coating contributed to fine grain size when Led was 73.33 J/mm2. On the other hand, the in-situ generation of TiC, TiB2 and TiC/TiB2 composite structure played an important role in achieving the more excellent propertiy in LaB6/FeCoNiCrTi composite coating. Furthermore, the microhardness and corrosion resistance of the coatings were significantly improved owing to the ceramic phases and fine grain strengthening. Specifically, the average microhardness coating was up to 593 HV0.2. The corrosion current density (Icorr) of the coating with a Led of 73.33 J/mm2 was 4.796 × 10−6 A·cm−2, the carrier density (ND) and thickness (d) of the passivation film were 1.556 × 1022 cm−2 and 3.244 nm, respectively, indicating the best corrosion resistance in HEA coatings. In terms of LaB6/FeCoNiCrTi coating, the Icorr, ND and d were 2.400 × 10−6 A·cm−2, 1.053 × 1022 cm−2 and 4.739 nm, respectively. Consequently, the doping of LaB6 further enhanced the corrosion resistance of HEA coating.

Effect of chemical bonding between fluorographene and fluororesin on the anti-corrosion properties of their composite coating

Fluorographene has unique advantages in the corrosion protection of heat exchangers. Excessive fluorographene loading can ensure the thermal conductivity performance of coatings, however, it also damages the coating integrity and reduces the corrosion resistance. Therefore, the project focuses on the effects of interfacial compatibility between fluorographene and polymer on the corrosion resistance of composite coatings. Fluorographene and fluororesin have been modified to prepare composite coatings (K-PFA). This modification improves the dispersion of fluorographene in the coating matrix and enhances the interface compatibility between the two materials. The crystallinity of the composite coating has increased from 33.66 % to 40.25 %. The corrosion protection performances of K-PFA are improved due to the reduction in water vapor and oxygen permeability by 83.8 % and 73.1 %, respectively, and the coating resistance of K-PFA is 3–4 times higher than that of blank coating. By utilizing surface modification techniques, the interface compatibility between fluorographene and the coating has been optimized, resulting in enhanced anti-corrosion properties for coatings.

Effects of graphene content in alkaline silicate electrolyte on AA1060 pure aluminum micro‐arc oxidation coating

AbstractCeramic coatings were obtained by micro‐arc oxidation (MAO) on the surface of AA1060 pure aluminum in alkaline silicate electrolyte with the addition of graphene. The effects of graphene contents in the range of 0–.30 g/L in the electrolyte on surface morphology, corrosion resistance, and wear resistance of the ceramic coatings were investigated. The outer surface structure, outer surface element content, coating cross‐section structure, coating cross‐section element content, coating/substrate interface structure, and coating phase were characterized by scanning electron microscope and X‐ray diffraction. Potentiodynamic polarization and electrochemical impedance spectroscopy were used to evaluate the corrosion behavior of MAO samples in a 3.5‐wt% NaCl solution. In addition, the resistance to sliding and abrasive wear of the oxide coating were studied experimentally. The results show that the alkaline silicate electrolyte with the addition of graphene has a significant effect on the characteristics of MAO coating. The performance of micro‐arc oxide coatings is best when the graphene content in the electrolyte is .15 g/L, the average thickness of the film is 7.24 μm, the average pore size is 6.07 μm, the impedance value is approximately 4.01 × 106 Ω, and its friction coefficient is .55.

Silicone and nano-diamond modified graphene oxide anticorrosive coating

Graphene oxide (GO) has abundant oxygen-containing functional groups, making it easy to undergo covalent and non-covalent modifications, coupled with its excellent physical barrier ability, which shows great prospects in improving the corrosion resistance of coatings. Unfortunately, GO has a strong van der Waals force and π-π interactions, which make it prone to self-aggregation, and at the same time, in the process of preparing the coating due to the volatilization of solvents, it is easy to produce micropores and other defects, which will not be conducive to the long-term corrosion resistance of the coating. Therefore, this work used silicone as a “bridge” to modify GO with nanodiamond, and then a composite coating with excellent anticorrosion properties was prepared with vinyl ester resin under heating conditions. This work not only effectively solved the dispersion and interface interaction of GO in the resin, but also the diluent in this process could fully participate in the polymerization reaction, effectively avoiding the volatilization of volatile gases. The results showed that the conductivity of the modified GO reached the level of the insulating material (9.6 × 10−9 S/cm, 30 MPa pressure). Electrochemical tests showed that the |Z|0.01Hz value of the coating was as high as 1.00 × 109 Ω cm2 after soaking in 3.5 wt% brine for 120 days, which was three orders of magnitude higher than the control group. Compared to the control group, the protective efficiency of the coating remained at 97.8 %. This was mainly related to the synergistic anticorrosion effect of GO and nano-diamond. In short, this work provided a new research approach for the preparation of long-lasting anticorrosion coatings using zero-dimensional and two-dimensional materials.

Relational model of compositions of enamel coatings and sintering temperature based on back propagation neural network algorithm

Declining the sintering temperature of enamel coatings is traditionally by reducing the content of network-forming agents (such as SiO2) and increasing the content of flux (for example, alkali metal oxides), which will lower the density of the [-Si-O-] network structure, and adversely affect the corrosion resistance of enamel coatings. To ensure a low sintering temperature of enamel coatings as much as possible under a high SiO2 content, it is essential to develop novel enamel coating formulas. However, abundant compositions of enamel coatings cause enormous verification workloads. To address this issue, this paper establishes a relational model of the compositions of enamel coatings and the sintering temperature using the back propagation (BP) neural network algorithm and proposes a formula that meets the requirement of lower the sintering temperature under a high SiO2 content. When the SiO2 content is 55 %, the sintering temperature can be diminished to around 400 °C. Furthermore, the influences of common enamel components on the sintering temperature are identified in this paper using the sensitivity algorithm. The obtained general law of formulas is that the total weight value of the formula at low sintering temperatures should be around −0.3. This paper can provide valuable theoretical guidance for subsequent research and expand the application range of enamel coatings.