Coating Technology Research Articles

Conductive, Anti-Corrosion, Self-Healing Smart Coating Technology Incorporating Graphene-Based Nanocomposite Matrix

Chromate conversion coatings have been in service for decades providing robust corrosion protection to a wide variety of aluminum alloys. However, it is also known that anti-corrosive coatings containing Cr6+ contributes to DNA damage, cause cancer and are not environmentally friendly. Consequently, regulatory restrictions over the use Cr6+ were established to mitigate the environmental damage and health problems. To answer to this hurdle and to meet the emergent need for environmentally friendly anti-corrosive coatings, we have successfully developed an innovative coating that combines anti-corrosive, low electrical resistance, and self-healing properties. First, we present two different coatings, that aim to display low electrical resistance properties: one containing only graphene and the other containing Zn nanoparticles and graphene. Confocal laser imaging and SEM microscopy was used to observe the morphology of the coatings. The electrical resistance was measured using the 4-wire connection Kelvin method. We compare the anticorrosive response for both coatings under neutral salt spray test (NSSt). Raman spectroscopy was performed before and after to understand the effect of NSSt corrosive species on the coatings. Then, we select the coating with lower electrical resistance, and we program on it a self-healing mechanism to boost its life service. Finally cyclic voltammetry is performed to confirm the excellent blocking properties of the tested coatings. All the coatings presented in this work are applied on aluminum AA 2024T351 and the optimal spray parameters for nanofillers dispersion are obtained. Our findings show great potential for preventing corrosion and compatibility with fully automated large-scale applications in different fields such as aerospace, automotive, construction, submarines and many more.

Influence of heat treatment on tribocorrosion properties of Ni-B composite coatings

Various surface protection technologies, in particular, electrochemical, are used to increase the wear and corrosion resistance of steels and alloys. Composite electrochemical coatings (CEC) technology is more promising than "pure" galvanic coatings. Application of CEC increases the wear, corrosion and fatigue failure resistance of metals. Nickel often is chosen as a CEC matrix because it easily forms uniformly filled defect-free composite structures with many particles of the dispersed phase (DP).
 Physical and mechanical properties of metal coatings determine practical application of such composition. The characteristics of nickel-based CEC are: high hardness and strength, significant corrosion resistance in atmospheric environment, as well as in alkali and mild acidy environments. An effective composition coating with tribological designation can be CEC Ni-B, received in the process of electrolysis from suspension of amorphous boron in nickel electrolyte. A new composite structure of matrix filled type Ni-Ni3B is formed after heat treatment. Composition and structure of coating is determined by regimes of diffusion annealing. Ni-B coatings increase wear resistance of steel in chlorine-based environments. The influence of low-temperature thermal treatment of Ni-B CEC on steel 09Mn2Si on their tribocorrosion behavior is investigated. It is shown that the structural factor has a decisive influence on the efficiency of such friction pairs. The CEC has the least wear and the most positive compromise electrode potential after vacuum annealing at 450°C, when the initial stage of solid-phase interaction of coating components with the formation of Ni-Ni3B occurs.

Surface Functionalization of Non-Woven Fabrics Using a Novel Silica-Resin Coating Technology: Antiviral Treatment of Non-Woven Fabric Filters in Surgical Masks.

Masks are effective for preventing the spread of COVID-19 and other respiratory infections. If antimicrobial properties can be applied to the non-woven fabric filters in masks, they can become a more effective countermeasure against human-to-human and environmental infections. We investigated the possibilities of carrying antimicrobial agents on the fiber surfaces of non-woven fabric filters by applying silica-resin coating technology, which can form silica-resin layers on such fabrics at normal temperature and pressure. Scanning electron microscopy and electron probe microanalysis showed that a silica-resin layer was formed on the fiber surface of non-woven fabric filters. Bioassays for coronavirus and quantitative reverse transcription-polymerase chain reactions (RT-PCR) revealed that all antimicrobial agents tested loaded successfully onto non-woven fabric filters without losing their inactivation effects against the human coronavirus (inhibition efficacy: >99.999%). These results indicate that this technology could be used to load a functional substance onto a non-woven fabric filter by vitrifying its surface. Silica-resin coating technology also has the potential of becoming an important breakthrough not only in the prevention of infection but also in various fields, such as prevention of building aging, protection of various cultural properties, the realization of a plastic-free society, and prevention of environmental pollution.

Development of DLC Film Coating Technology to Achieve both High Performance and High Productivity Utilizing High-Density Plasma

Development of DLC Film Coating Technology to Achieve both High Performance and High Productivity Utilizing High-Density Plasma

Analysis of Anticorrosion Coating and Cathodic Protection Technology for Long Distance Natural Gas Pipeline

Analysis of Anticorrosion Coating and Cathodic Protection Technology for Long Distance Natural Gas Pipeline

АДГЕЗИОННЫЕ ХАРАКТЕРИСТИКИ ТОНКОПЛЕНОЧНОГО ПОКРЫТИЯ, ОСАЖДАЕМОГО ПРИ ФИНИШНОМ ПЛАЗМЕННОМ УПРОЧНЕНИИ

The methodology for determining adhesion characteristics of thin-film coatings applied from the vapor phase and used to protect parts against wear and corrosion has been considered. The study of adhesion properties, along with deter-mination of thickness, composition of elements, structure, physical-mechanical, and tribological characteristics, as well as wear coefficient, al-lows evaluating and selecting the optimal coat-ing and best technology for its application for a specific industrial application. On the example of studying DLCPateks diamond-like coating of aC:H/a-SiOCN system deposited during final plasma hardening, adhesion characteristics were assessed according to ISO 20502:2005 by scratch testing and according to ISO 26443:2008 by indentation of Rockwell diamond indenter. The first tests were performed to determine the load at which the depth of penetration of the indenter into the coating - substrate composition stops growing smoothly, which characterizes the moment of destruction of the coating. The ratio of the load on the indenter, determined at the end of the passage of the coating thickness, to the load of occurrence of the first cracks or delamination, in these tests is conventionally called the adhesion coefficient. The influence of the coating thickness on the adhesion coefficient has been studied. The tests associated with the use of a Rockwell diamond indenter punch qualitatively evaluate the adhesion properties of the coating by comparing the obtained and normalized impressions. The results of the tests proved improved adhesion characteristics of DLCPateks coating.

Anti-Corrosion Coatings Based on Nb2O5 - a Comparison Between two Coatings Technology: Thermal Spray Coating and Epoxy Paint

Anti-Corrosion Coatings Based on Nb2O5 - a Comparison Between two Coatings Technology: Thermal Spray Coating and Epoxy Paint

Study of the optical properties of poly (methyl methacrylate) (PMMA) by using spin coating method

In this paper, thin films of poly (methyl methacrylate) [PMMA] were created using the spin coating process. Using Spin Coating technology, PMMA was produced and deposited on glass slides at three distinct rates ranging from 1000 to 3000 revolutions per minute. The speed was used to create a thin film of a specific thickness because the faster the speed, the thinner the film, and vice versa. Changes in optical parameters such as absorbance and transmittance spectra as a function of wavelength, as well as the absorption coefficient and other optical constants, have been measured. The absorbance, absorption coefficient, and refractive index values of pure polymer increase as the PMMA concentration ratios increase. The results showed a decrease in transmittance values with all PMMA concentration ratios. The values of reflectance increase as the concentration ratio increases; additionally, the results show a decrease in the energy gap for allowed direct transition as the concentration ratio increases of PMMA.

ОТРИМАННЯ ПЕРЕВ’ЯЗОЧНИХ МАТЕРІАЛІВ З НАНОЧАСТИНКАМИ СРІБЛА ЗА ДОПОМОГОЮ МЕТОДІВ ФІЗИЧНОГО ОСАДЖЕННЯ У ВАКУУМІ

Purpose. Adapt electron beam equipment to obtain nanosized silver structures on the surface of dressings with the ability to control the size and concentration of the resulting nanoparticles (NPs). Determine the morphology, forum, size distribution and concentration of the obtained silver nanoparticles. Methodology. Modern methods of analysis are used in the work. Electron beam evaporation method with directional vapor deposition in vacuum was used to obtain nano-particles on a flat surface. To determine the structural characteristics nanoparticles: the size of the phase formations, the morphology we were used metods: dynamic light scattering (DLS); transmission electron microscopy (TEM); the con-centration of silver in dispersed systems was determined by the method of atomic emission spectrometry with induc-tively coupled plasma (NPP ISP). Results..The results of the study demonstrate the possibility of using electron-beam deposition technology of discrete nanosized silver coatings with an average particle size of 25 nm and a dispersion of 10–120 nm on the surface of sterile gauze bandages. The established patterns of structure formation can be the basis for technically controlled synthesis of metal nanoparticles on the surface of textile materials with a given concentra-tion.Existing research and industrial and industrial electron beam equipment can be easily adapted to the production of these materials. Originality. A new technological scheme of EB-PVD with directed steam flow, the efficiency of which is ≈50%, is proposed. This scheme allows the deposition of steam from the mountain to the bottom, including on flat surfaces of banding materials. Practical value. Areas of practical application of NPs and compositions based on them can be divided into the following areas: providing or enhancing antiviral and antimicrobial properties of new or existing medical devices (bandages, masks, wipes).

Hot corrosion behavior of an arc sprayed Fe-based amorphous coating in a simulated biomass firing environment

Coating technologies are cost-effective solutions to the Cl-induced hot corrosion problems in biomass boilers. In this study, an arc sprayed Fe-Cr-Mo amorphous coating was fabricated and exposed to a stimulated biomass firing condition at 500 °C and 600 °C. Fe and Cr in the coating were vulnerable to chlorination and continuously evaporated, leaving Cr depletion zones. The distribution of Mo was inhomogeneous, and Mo-rich zones were resistant to gaseous corrosive species but susceptible to electrochemical attack as temperature increased. The crevices in the coating were detrimental to its corrosion resistance by acting as corrodent diffusing channels.

Research on Anti-Corrosion and Coating Technology of Outer Pipes of Submarine Pipelines Shallow Sea by Physical Testing

In this paper, by discussing the characteristics of the beach and shallow sea marine environment, combining with engineering design and application, studying the anti-corrosion coating and coating technology of the outer pipe of the pipeline, and analyzing the design of the concrete counterweight layer of the submarine pipeline. According to the submarine pipeline of the environment, structural characteristics, construction methods, etc, the reasons for the damage of the external protective coating under certain conditions are explained, so as to select the external protective coating more reasonably, and provide data for the anti-corrosion and coating selection of the marine pipeline.

Modelling Electrochemical Polishing of Additive Manufactured Parts. Limits and Improvements of Secondary Distribution Model in Circulating Flow

Additive manufacturing allows to design and to realize parts with complex geometries, which were difficult, even impossible, to obtain by conventional means. Nevertheless, the final surface finish obtained at the end of the 3D printing process do not fit with technological specifications especially due to high roughness levels. Thus, an additional finishing step must be implemented in order to get the expected surface finish. Electrochemical polishing (ECP) is showing promising results for smoothing SLM parts with high complex shapes. ECP is an electrolytic process based on the anodic dissolution of the workpiece under constant current or potential [1]. As it is done for electroplating systems, it is nonetheless necessary to uniformize the distribution of current lines in the treatment cell, in order to make the dissolution as homogeneous as possible on the whole surface. Indeed, the concentration of the current lines on the edges causes a greater dissolution which is detrimental to the geometric integrity of the parts. The ability to provide a trustworthy simulation of the process by the help of an accurate modelling is a major issue to ensure its industrial deployment through the development of specific tools and the selection of relevant operating parameters. To this end, the use in a first approach of a secondary current distribution model gives interesting results in term of dissolution rates. However, this approach faces limitations and it is difficult to predict roughness evolution as a result of the specificity of electropolishing processes i.e. wide potential ranges and the presence of a viscous layer. Moreover, parts after treatment present heterogeneities depending to their position in the electrolyte flow circulation, which can be explained by the presence of turbulences in the vicinity of the impact zone. In order to understand and contribute to the global model improvement, mechanisms involved at a microscopic scale have been investigated with a special attention paid to the influence of hydrodynamic on mass and heat transfer exchanges. Microscopic behaviors are described, and their sensitivity to global parameters (temperature, liquid flow velocity..) are studied to help to take into account the impact of fluid dynamics and / or heat transfers on the viscous layer, which governs the polishing.[1] C. Rotty, A. Mandroyan, M-L. Doche, J-Y. Hihn, Surface & Coatings Technology vol.307 p125–135 (2016).[2] V. Urlea, V. Brailovski, Int. J. Adv. Manuf. Technol. vol.92 p4487–4499 (2017).

A Versatile Light‐Triggered Radical‐Releasing Surface Coating Technology

AbstractOrganic based redox active materials and coatings are increasingly being investigated as solutions for more efficient energy devices, catalysts, sensors, and biomedical technologies. Their advantage is negating the necessity for expensive and unsustainable rare earth metals seen in other redox active materials. Challenges to their wide‐spread usage remain, including versatility of coatings on a wide range of substrates, and creating smart devices that can respond to environmental stimuli. A new light responsive radical releasing redox coating has been developed, that can be rapidly and stably applied to a diverse range of substrates including silicon dioxide, plastics, and microparticles. These coatings rapidly cleave upon irradiation with UV‐A light to release stable nitroxides from the surface coating. These coatings are developed into microparticle sensors for radical oxygen species, which are able to detect the generation of free radicals in a model system for particulate matter pollution. These new responsive organic redox coatings also offer future potential to function as switchable organic electrodes, and biomedical surface coatings to prevent biofouling and reduce inflammation.

Corrigendum to “On the S/W stoichiometry and triboperformance of WSxC(H) coatings deposited by magnetron sputtering” [Surface and Coatings Technology 365 (2019) 41-51

Corrigendum to “On the S/W stoichiometry and triboperformance of WSxC(H) coatings deposited by magnetron sputtering” [Surface and Coatings Technology 365 (2019) 41-51

Finding Use for Sorghum Bicolor Leaf Sheath in Coating Technology

This study aimed to investigate the potential use of aqueous extract of Sorghum bicolor leaf sheath (SBLS) as a coating agent for paracetamol tablets. The mechanical properties of the coated tablets were assessed using crushing strength and friability test, while the release properties of the tablet were evaluated using disintegration and dissolution tests. The physicochemical properties of the coated tablets did not show any striking differences when compared with the uncoated tablet as par compendium specifications, which formed the basis for performing further in vitro dissolution study. Our data showed that SBLS enhanced the hardness and friability of the tablets in a dose-dependent manner. Tablets coated with 3, 5, and 7.5% of SBLS disintegrated in 8.13, 6.25, and 4.13 minutes, respectively, while the uncoated tablet disintegrated in 0.7 minutes. Furthermore, 3, 5, and 7.5% of SBLS-coated tablets exhibited slower release of their active ingredient (releasing 21, 16, and 17%, respectively) than that of the uncoated tablet (releasing 40%) in 5 minutes. Besides, comparison between the dissolution profiles was successfully achieved using difference factor (f1) and similarity factor (f2). The apparent dissimilarity between our coated tablets and the uncoated one led to further study of convolution in vitro–in vivo correlation, with the aim to obtain data that converted into mathematical prediction of in vivo data. For all batches, the percent predictable errors of C max and T max were within the acceptable limit of no more than 10%. In summary, SBLS aqueous extract is a potential and protective coat agent for paracetamol tablets. The in vitro established dissolution of the coated tablets provided scientific information for the prediction of the in vivo plasma drug profile.

New Advances in Powder Coating Technology

New Advances in Powder Coating Technology

Electrodeposition of Zinc-Nickel Alloys from Ethylene Glycol for Corrosion Protection

Zn rich ZnNi alloys electrodeposition have recently attracted the attention of researchers due to their interesting corrosion properties [1]. In particular, alloys containing Ni in the 15 - 25 % range find application in a number of industrial fields, like automotive and constructions. ZnNi is normally electrodeposited from aqueous solutions, in which plating takes place following a typical anomalous mechanism [2]. In the last few years, however, new deposition approaches have been attempted to improve ZnNi plating performances. Specifically, III generation deep eutectic solvents comprising choline chloride have been tested [3].The present work investigates the use of non-aqueous ethylene glycol based electrolytes for the deposition of Zn rich ZnNi alloys. The use of ethylene glycol as solvent introduces many advantages with respect to aqueous solutions: low oxygen contamination, high deposits purity and no pH dependance [4]. ZnNi codeposition was studied employing cyclic voltammetry and layers were deposited under potentiostatic control. Deposition potential was varied and its influence on final composition and morphology was determined. Addition of an additive (NH4Cl) to enhance surface morphology was attempted as well [3]. Phase composition was investigated using XRD to determine the possible presence of a metastable γ-ZnNi phase, which has already been observed in the case of ZnNi plated from alkaline aqueous solution [5]. Finally, corrosion behavior of layers obtained from ethylene glycol was assessed and compared with equivalent coatings deposited from commercial aqueous solutions.[1] M. Gavrila et al.; Surface and Coatings Technology, 123 (2-3), 164-172 (2000)[2] G. Roventi et al.; Journal of Applied Electrochemistry 30 (2), 173–179 (2000)[3] S Fashu et al.; Transactions of Nonferrous Metals Society of China 25 (6), 2054-2064 (2015)[4] G. Panzeri et al.; Electrochimica Acta 271 (1), 576-581 (2018)[5] S. Ieffa et al.; Transactions of the IMF 94, 321-324 (2014)

Effect of Water-Based Emulsion Core Microcapsules on Aging Resistance and Self-Repairing Properties of Water-Based Coatings on Linden

The purpose of this paper was to discuss the best coating technology of water-based coatings containing microcapsules, and the anti-aging and self-repairing properties of water-based coatings containing microcapsules. Urea-formaldehyde encapsulated Nippon water-based emulsion microcapsules were prepared, and water-based coatings containing microcapsules were prepared. The optical and mechanical properties of the coatings under different coating technologies were investigated. Under the best coating technology, the aging resistance and self-repairing performance of the coating film were investigated. Experimental results showed that coating technology had no effect on color aberration of the coating film. The coating technology with two coats of primer, three coats of topcoat, addition of microcapsules into primer, had excellent glossiness, shock resistance of 12.0 kg·cm, adhesion of 0 grade, and fracture elongation of 26.3%. Compared with the coating film without microcapsules, the coating with microcapsules had better aging resistance and self-repairing property, and the self-repairing rate was about 20.0%. Compared with the paint film with Dulux water-based emulsion microcapsules, the paint film with Nippon water-based emulsion microcapsules had a higher self-repairing rate. This study provides a technical basis for self-repairing water-based coatings.

Sensitive Materials and Coating Technologies for Surface Acoustic Wave Sensors

Since their development, surface acoustic wave (SAW) devices have attracted much research attention due to their unique functional characteristics, which make them appropriate for the detection of chemical species. The scientific community has directed its efforts toward the development and integration of new materials as sensing elements in SAW sensor technology with a large area of applications, such as for example the detection of volatile organic compounds, warfare chemicals, or food spoilage, just to name a few. Thin films play an important role and are essential as recognition elements in sensor structures due to their wide range of capabilities. In addition, other requisites are the development and application of new thin film deposition techniques as well as the possibility to tune the size and properties of the materials. This review article surveys the latest progress in engineered complex materials, i.e., polymers or functionalized carbonaceous materials, for applications as recognizing elements in miniaturized SAW sensors. It starts with an overview of chemoselective polymers and the synthesis of functionalized carbon nanotubes and graphene, which is followed by surveys of various coating technologies and routes for SAW sensors. Different coating techniques for SAW sensors are highlighted, which provides new approaches and perspective to meet the challenges of sensitive and selective gas sensing.

Study on High-efficiency Thermal Conductive Anticorrosion Coating Technology for Temperature and H2S Corrosion Resistance

In order to deal with the anticorrosion problem of heat exchangers containing H2S, CO2 and other acidic media, the heat-conducting anticorrosion coating which can be used in acidic media at 200°C was prepared by adopting the combination system of the high-temperature curing epoxy phenolic resin film forming system and acid-resistant filler and filled heat-conducting filler. The results show that the coating has excellent acid and alkaline resistance, salt spray resistance, heat resistance and good thermal conductivity. It meets the technical requirements of heat exchanger corrosion protection under the acidic corrosion environment of H2S and CO2.