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1 – 10 of over 1000Guosheng Huang, Xiangbo Li and Lukuo Xing
This paper aims to examine the performance of low-pressure cold-sprayed zinc–nickel (Zn-Ni) composites coating, i.e. whether it has the same performance as Zn-Ni alloy coating.
Abstract
Purpose
This paper aims to examine the performance of low-pressure cold-sprayed zinc–nickel (Zn-Ni) composites coating, i.e. whether it has the same performance as Zn-Ni alloy coating.
Design/methodology/approach
In this paper, Zn-Ni composites coatings containing four different nickel contents were prepared with commercial DYMET 413 low-pressure cold spraying system under the same parameters. Corrosion behaviors of four kinds of coatings were examined with potentiodynamic polarization curves and electrochemical impedance spectroscopy methods, combined with scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction.
Findings
Corrosion behavior of Zn-Ni composites coating is similar to Zn-Ni alloy coating. In the early stages of immersion, the anodic dissolution of zinc happens, which results in the formation of a zinc hydroxide layer. With the continuous infiltration of chloride ion, zinc hydroxide will get converted to zinc oxide, basic zinc chloride and basic zinc carbonate. The presence of nickel in coatings can prevent zinc hydroxide from converting into zinc oxide.
Research limitations/implications
Further research should be done on improving the deposition efficiency, as the deposition efficiency of low-pressure cold spray is lower than 30 per cent.
Practical implications
Low-pressure cold spray coating can be used in cyclic dry/wet conditions to prolong the life of a steel structure.
Social implications
Low-pressure cold spray Zn-Ni coating is an environmentally friendly anticorrosion method which can be used as an alternative of hexavalent chromium passivation coating.
Originality/value
Zn-Ni composite coating can be deposited on steel directly by low-pressure cold spray by mechanically mixing the powders together. The composite coating also has the same long-term anticorrosion performance as Zn-Ni alloy coating.
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Santosh Kumar, Manoj Kumar and Neeru Jindal
This paper aims to consolidate the results of various researchers focusing the different applications, so that this paper could become the torch bearer for the futuristic…
Abstract
Purpose
This paper aims to consolidate the results of various researchers focusing the different applications, so that this paper could become the torch bearer for the futuristic researchers working in the domain of cold gas dynamics spray coating.
Design/methodology/approach
A study on the cold spray coating is presented by summarizing the data present in literature. Important factors such as coating temperature, pressure, coating thickness, particle size, which affect the erosion-corrosion (E-C) resistance, physical and mechanical properties of boiler steel are stated. This paper also addresses the use of cold spray coating and compares it with other different thermal spray processes.
Findings
From the literature review, it was noticed that cold spray technology is best as compare to other thermal spray processes to reduce porosity, increase hardness, adhesion strength and retention in properties of feedstock powders.
Originality/value
Cold spray coating technology has a great potential in almost every field especially in restoration of surfaces, generation of complex surface, biomedical application, resist hot corrosion, wear, oxidation and erosion corrosion.
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Keywords
Guosheng Huang, Wei Fu, Juan Zhou, Li Ma, Hongren Wang and Xiangbo Li
The purpose of this paper is to examine the performance of cold-sprayed Zn15Al alloy coating whether it is capable of protecting magnesium alloy from corrosion, and to compare it…
Abstract
Purpose
The purpose of this paper is to examine the performance of cold-sprayed Zn15Al alloy coating whether it is capable of protecting magnesium alloy from corrosion, and to compare it with arc-sprayed Zn15Al alloy coating.
Design/methodology/approach
In this paper, Zn15Al alloy coating was prepared with CS-6000 cold spraying system and HDX-800 arc-sprayed system. Corrosion behaviors of the two kinds of coatings were examined with potentiodynamic polarization curves methods combined with SEM, EDS, XRD, etc.
Findings
Corrosion behavior of cold-sprayed Zn15Al alloy coating is superior to arc-sprayed Zn15Al alloy coating. The bonding strength and density of cold-sprayed Zn15Al alloy coating is much higher than that of arc-sprayed Zn15Al alloy coating. The cold-sprayed coating has a dense structure which separate magnesium from corrosion medium completely. The samples behave as Zn15Al instead of AZ91D alloy. The coating has a low probability of pitting corrosion comparing with cold sprayed Al coating through potentiodynamic polarization curve.
Practical implications
Cold-sprayed Zn15Al coating can be used to improve the anticorrosion performance of magnesium significantly and low down the risk of pitting corrosion of coating.
Social implications
Cold-sprayed Zn15Al coating is an environmentally friendly anticorrosion method for light alloy, which is also the most effective way among thermal spray, chemical vapor deposition, sol–gel, plating and anodizing or microarc oxidation.
Originality/value
The present paper used cold spray method to deposit Zn15Al coating, which has an overwhelming performance both in physical and anticorrosion to traditional thermal spray method.
Details
Keywords
Wang Zhizhong, Han Chao, Guosheng Huang, Han Bin and Han Bin
The deposition of particles onto a substrate during the cold spraying (CS) process relies on severe plastic deformation, so there are various micro-defects induced by insufficient…
Abstract
Purpose
The deposition of particles onto a substrate during the cold spraying (CS) process relies on severe plastic deformation, so there are various micro-defects induced by insufficient deformation and severe crushing. To solve the problems, many post-treat techniques have been used to improving the quality by eliminating the micro-defects. This paper aims to help scholars and engineers in this field a better and systematic understand of CS technology by summarizing the post-treatment technologies that have been investigated recently years.
Design/methodology/approach
This review summarizes the types of micro-defects and introduces the effect of micro-defects on the properties of CS coating/additive manufactured, illustrates the post-treatment technologies and its effect on the microstructure and performances, and finally outlooks the future development trends of post-treatments for CS.
Findings
There are significant discoveries in post-treatment technology to change the performance of cold spray deposits. There are also many limitations for post-treatment methods, including improved performance and limitations of use. Thus, there is still a strong requirement for further improvement. Hybrid post-treatment may be a more ideal method, as it can eliminate more defects than a single method. The proposed ultrasonic impact treatment could be an alternative method, as it can densify and flatten the CS deposits.
Originality/value
It is the first time to reveal the influence factors on the performances of CS deposits from the perspective of microdefects, and proposed corresponding well targeted post-treatment methods, which is more instructive for improving the performances of CS deposits.
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Cagdas Calli, Onur Tazegul and Eyup Sabri Kayali
The purpose of this paper is to investigate the effects of reinforcing particles (B4C, TiB2 and TiC) on the physical, corrosion and wear behaviour of copper matrix composite…
Abstract
Purpose
The purpose of this paper is to investigate the effects of reinforcing particles (B4C, TiB2 and TiC) on the physical, corrosion and wear behaviour of copper matrix composite coatings.
Design/methodology/approach
Coatings were produced by cold gas dynamic spraying process, and the contribution of reinforcements (B4C, TiB2 and TiC) to the coating characteristics was detected through microstructural examinations (scanning electron microscope examinations and X-ray diffraction analyses), hardness and electrical conductivity measurements, corrosion tests in Cl− environment with potentiostat/galvonostat apparatus and wear tests which were performed under dry conditions by reciprocating wear tester.
Findings
Coatings with high density, good bonding at the coating and substrate interface were obtained by cold gas dynamic spray process. The electrochemical polarisation test in a Cl− environment clearly indicated that the type of reinforcing particles did not significantly affect the corrosion performances of pure copper coating. In terms of the wear performances of the coatings, the best wear performance has been obtained for pure copper coating. Wear performance reduction of the composite coatings was related to the inhibition of continuous oxide layer formation on the worn surfaces due to third-body abrasion mechanism and delamination of oxide layer during wear tests.
Originality/value
Contrary to expectations, wear tests results of the study revealed the inverse effect of ceramic particle addition to the copper matrix in cold spray coating applications due to poor bonding between matrix and reinforcing particles.
Details
Keywords
Thi Thanh Huong Nguyen, Nam Pham Thi, Thang Le Ba, Vy Uong Van, Bao Le Duc and Tuan Anh Nguyen
This study aims to enhance to corrosion protection of NiZn-plated steel by electroplating multilayer coating.
Abstract
Purpose
This study aims to enhance to corrosion protection of NiZn-plated steel by electroplating multilayer coating.
Design/methodology/approach
The multilayer coating consists of three layers on mild steel substrate, such as Cr3+ chromate conversion layer (CCC), electrodeposited nanosilica zinc-nickel composite layer (ZnNiSi) and electrodeposited zinc-nickel alloy layer (ZnNi). Its morphology, composition and corrosion behaviour were investigated by various methods.
Findings
Polarization curves indicated that polarization resistance and corrosion current density of CCC/ZnNiSi/ZnNi/Fe (6.956 kO.cm2; 2.56 µA.cm−2) were two times higher and five times lower than that of ZnNiSi/ZnNi/Fe (3.42 kO.cm2; 12.52 µA.cm−2), respectively. From electrochemical impedance spectroscopy data, charge transfer resistances were 1.344, 2.550 and 2.312 kO.cm2 for ZnNi, ZnNiSi/ZnNi and CCC/ZnNiSi/ZnNi, respectively. Salt spray test indicated that after 48 h, surface of ZnNi and ZnNiSi was covered by white rust, whereas no white rust was observed on surface of CCC/ZnNiSi/ZnNi. After 600 h, there were red rust spots (1% surface coverage) on surface of Zn-Ni, whereas only white rust was observed on both ZnNiSi/ZnNi (100% surface coverage) and CCC/ZnNiSi/ZnNi (10% surface coverage).
Originality/value
Multilayer coating enhanced significantly the corrosion protection for steel, as compared to the single-layer coating.
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Gus Nasif, R.M. Barron, Ram Balachandar and Julio Villafuerte
Application of cold spray technology may exhibit significant benefits for the additive manufacturing process, particularly for producing intricate objects. To ascertain the…
Abstract
Purpose
Application of cold spray technology may exhibit significant benefits for the additive manufacturing process, particularly for producing intricate objects. To ascertain the feasibility of such an application, this paper aims to present a numerical investigation of the effect of scaling down a convergent-divergent (de Laval) nozzle, which is typically used in the cold spray industry, on the compressible flow parameters and thermal characteristics.
Design/methodology/approach
The Navier–Stokes equations and energy equation governing compressible flow are numerically solved using a finite volume method with a coupled solver. The conjugate heat transfer technique is used to couple fluid and solid heat transfer domains and predict the local heat transfer coefficient between the solid and fluid. The use of various RANS turbulence models has also been investigated to quantify the effect of the turbulence model on the simulation.
Findings
The numerical results reveal that the flow and thermal characteristics are altered as the convergent-divergent nozzle is scaled down. The static pressure and temperature profiles at any section in the nozzle are shifted toward higher values, while the Mach number profile at any section in the nozzle is shifted toward a lower Mach number. The turbulent kinetic energy at the nozzle exit increases with the scaling down of the nozzle geometry. This study also provides convincing evidence that the adiabatic approach is still suitable even though the temperature of the nozzle wall is extremely high, as required for industrial application. Results indicate that it is feasible to use the available capabilities of the cold spray technology for additive manufacturing after scaling down the nozzle.
Originality/value
The idea of adopting cold spray technology for additive manufacturing is new and innovative. To develop this idea into a viable commercial product, a thorough understanding of the flow physics within a cold spray nozzle is required. The simulation results discussed in this paper demonstrate the effect that scaling down of a convergent-divergent nozzle has on the flow characteristics in the nozzle.
Details
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Jaroslaw Sienicki, Wojciech Zórawski, Adam Dworak, Piotr Koruba, Piotr Jurewicz and Jacek Reiner
The purpose of this paper is to propose cold spraying and laser cladding processes as alternatives to cadmium and chromium electroplating, respectively. There are many substances…
Abstract
Purpose
The purpose of this paper is to propose cold spraying and laser cladding processes as alternatives to cadmium and chromium electroplating, respectively. There are many substances or chemicals within the coating technology that can be identified as substances of very high concern because of their carcinogenic or mutagenic nature. Cadmium and chromium undoubtedly belong to these items and are the basic constituents of electrolytic coating processes. Finding an alternative and adapting to the existing restrictions of the usage of such hazardous products stands for many to be or not to be in the market.
Design/methodology/approach
The research work was focused on down selecting the appropriate materials, producing the coating samples, testing their properties and optimizing process parameters by statistical method. On the one hand, the high-pressure cold spray system and spraying of the titanium coating on the landing gear component, and on the other hand, the high-energy laser cladding facility and the wear resistant cobalt-based coating deposited onto the shock absorber piston. Substrates of these two applications were made of the same material, 4330 – high-strength low-carbon steel.
Findings
Meeting the requirements of Registration, Evaluation, Authorization and Restriction of Chemicals implies undertaking research and implementation work to identify alternative processes. The work provides the technical characteristics of new coatings justifying application readiness of the researched processes.
Originality/value
Taguchi’s design of experiment method was combined with the measurements and analysis of specified coating properties for the optimization of the cold spray process parameters. There is also laser cladding process development presented as a fast rate technology generating coatings with the unique properties.
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Zhang Jing and Kong Dejun
To improve the electrochemical corrosion resistance of cold sprayed Al coating.
Abstract
Purpose
To improve the electrochemical corrosion resistance of cold sprayed Al coating.
Design/methodology/approach
A cold sprayed aluminum (Al) coating fabricated on S355 structural steel was oxidized using a micro arc oxidation (MAO). The electrochemical corrosion and impedance spectroscopy were tested to investigate its corrosion performance.
Findings
The MAO film is primarily α-Al2O3 and γ-Al2O3, which increases its density and surface quality. The corrosion potential is positively shifted by 0.2 V, and the electrochemical impedance is significantly increased.
Originality/value
A cold sprayed Al coating on S355 steel was first oxidized using a MAO. The effects of MAO on the microstructure of Al coating were investigated to analyze its electrochemical corrosion behavior.
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The use of low‐boiling solvents, low air pressure and heated‐hose delivery, allow spray painting jobs to be carried out quickly and effectively without incurring the drawbacks of…
Abstract
The use of low‐boiling solvents, low air pressure and heated‐hose delivery, allow spray painting jobs to be carried out quickly and effectively without incurring the drawbacks of high‐pressure hot paint spraying.