Cold Spray Technology Research Articles

Sars-CoV-2 (COVID-19) inactivation capability of copper-coated touch surface fabricated by cold-spray technology

In this work, cold-spray technique was employed for rapid coating of copper on in-use steel parts. The primary intention was to alleviate the tendency of SARS-CoV-2 (COVID-19) virus to linger longer on touch surfaces that attract high-to-medium volume human contact, such as the push plates used in publicly accessed buildings and hospitals. The viricidal activity test revealed that 96% of the virus was inactivated within 2-hrs, which was substantially shorter than the time required for stainless steel to inactivate the virus to the same level. Moreover, it was found that the copper-coated samples significantly reduces the lifetime of COVID-19 virus to less than 5-hrs. The capability of the cold-spray technique to generate antiviral copper coating on the existing touch surface eliminates the need for replacing the entire touch surface application with copper material. Furthermore, with a short manufacturing time to produce coatings, the re-deployment of copper-coated parts can be accomplished in minutes, thereby resulting in significant cost savings. This work showcases the capability of cold-spray as a potential copper-coating solution for different in-use parts and components that can act as sources for the spread of the virus.

Recent Advances of Cold Spray Technologies in Nuclear Energy Applications

Abstract Cold spraying is a potentially attractive method for producing accident tolerant fuel cladding, near-net shape nuclear reactor components, and nuclear fuel storage canisters.

Development status of Anti-corrosion Technology for Power Transmission Tower’s Steel Structure

Higher requirements have been brought forward on the reliability and service life of power transmission tower’s steel structure along with the growing of power generation capacity. This paper analyzes types of corrosion of power transmission tower’s steel structure and the status of research on corrosion and summarizes categories of protective coating for steel and iron materials. Hot-dip galvanizing still remains as the main anti-corrosion method for power transmission tower’s steel structure in China, while the promotion and application of cold spray technology, cold zinc-spraying anti-corrosion technology and weathering resistant steel provide more options of anti-corrosion technologies for power transmission tower. The engineering practice proves that cold zinc-spraying anti-corrosion technology has achieved superior application effects in on-site reinforcement and repair of power transmission tower.

SURFACE REPAIR OF AIRCRAFT TITANIUM ALLOY PARTS BY COLD SPRAYING TECHNOLOGY

Titanium alloys have the advantages of high specific strength, good corrosion resistance, high heat resistance, and low density, which is the main structural material of aerospace system components, including compressor blade, cartridge receiver, blisk, engine nacelle, thermal baffle and so on. At present, about three-quarters of titanium and titanium alloys in the world are used in the aerospace industry, including A350 for 14%, F18 for 15 %, B787 for 15 %, SU-57 for 18 %, J-20 for 20 %, FC-31 fighters for 25 %, F35 for about 27 %, and F22 up to 41 %, etc, so it has the reputation of "space metal". However, its low wear resistance limits the further development of titanium alloy. Besides, its high manufacturing cost, if only require the occasion of surface performance can reduce the use of the substrate, and then reduced the cost. Therefore, the study of aircraft titanium alloy is of great significance, the protection of titanium alloy includes alloying technology and coating technology. Alloying technology mainly adds other elements on its basis to improve the performance, while the most popular method is coating technology, the present, there are many coating technologies, include high-velocity oxy-fuel (HVOF), HVAF, cold spraying, laser cladding, laser micro-fusion in-situ synthesized technology, micro-arc oxidation, laser melt injection (LMI), supersonic laser deposition (SLD) and supersonic plasma spray technology, surface repair titanium alloy parts by cold spraying technology are good ways to solve those problems. Because of its low process temperature, no oxidation, only plastic deformation, and repair efficiency are high, the protective coating has high bonding strength and good impact toughness. In this paper, the types and applications of aircraft titanium alloys were reviewed, the latest research results of surface repair of titanium alloys parts by cold spraying technology were reviewed, technological parameters of the cold gas dynamic spraying technology was analyzed, including powder size of particles, morphologies, critical velocity, particle compression rate, substrate preheating effects on the particle/substrate adhesion, etc.

REVIEW OF MANUFACTURING AND REPAIR OF AIRCRAFT AND ENGINE PARTS BASED ON COLD SPRAYING TECHNOLOGY AND ADDITIVE MANUFACTURING TECHNOLOGY

Cold spray technology is a method of deposited metal coatings by high-speed particle impact, especially in the preparation of metal alloy materials (Cu alloys, Ti alloys, Al alloys, Ni-based alloys, Mg alloys, stainless steels, and high-temperature alloys, etc.) The performance is particularly outstanding. The sprayed materials have better mechanical properties, mechanical properties, and service life, such as tensile strength, fatigue strength, and corrosion resistance. Cold spray technology can prepare corrosion-resistant coatings and high-temperature coatings, Wear-resistant coatings, conductive coatings, and anti-oxidation coatings and other functional coatings. From the perspective of process technology and equipment design, cold spray technology can be applied to the field of additive manufacturing technology, which not only reflects the repair function but also the manufacturing function, and applies cold spray technology and repairs the parts produced by additive manufacturing – Selective Laser Melting technology. The defects and problems are of great significance. This article summarizes the repair process and technical characteristics of cold spray technology, and repairs and protects the Cu, Ti, Al, Ni, Mg, and stainless steel and other metals and their alloys from corrosion, fatigue, and wear. The maintenance is reviewed, and the application of combining cold spray technology with additive manufacturing – Selective Laser Melting technology is proposed. Many materials can be used in the field of cold spray technology and Additive Manufacturing – Selective Laser Melting technology. In the communication between the two, the combination of technology and method is of great significance; the influence of spraying parameters of cold spraying technology (such as powder particle shape, spraying angle, spraying distance, critical speed and temperature of particles and substrate, etc.) on spraying effect and efficiency are proposed. Finally, the development of cold spray technology: post-processing of parts, critical speed and numerical simulation are possible.

Microstructure, hardness and cavitation erosion resistance of different cold spray coatings on stainless steel 316 for hydropower applications

There is an urgent need for repair of hydropower components that have undergone damage due to cavitation. This study investigated the relevant properties of different materials using cold spray technology. Stainless steel (SS) 316, Inconel 625 and CrC-NiCr materials were deposited onto base metal SS 316 using cold spray. Cold spray achieved deposits with relatively low porosities, and intimate contact between the deposit and the base metal was observed. Severe plastic deformation was imparted during the cold spray process and nanostructured regions were observed in all three deposits across the interfacial area. Cold sprayed deposits exhibited elevated hardness in contrast to that of the base metal SS 316. The cavitation erosion resistance of the deposits was evaluated with a cavitation erosion jet adhering to ASTM G134 standard. Both Inconel 625 and SS 316 achieved better cavitation erosion resistance when compared to the base metal SS 316, with cold sprayed Inconel 625 having close to a four times improvement.

Fatigue performance of cold spray deposits: Coating, repair and additive manufacturing cases

Cold spray technology has recently gained much attention for applications beyond its primary cause of protective coating deposition. It has found its way for depositing thin films for surface functionalization, thick coatings for geometrical restoration, and has exhibited a high potential for additive manufacturing. As cold spray paves its way towards more structural applications, evaluating its performance under cyclic loading is of significant importance. Herein, the current state of the art on the contribution of various forms of cold spray deposits to fatigue strength is reviewed. Future perspectives for enhancing their structural integrity and promising trends are discussed.

Structural integrity of additively manufactured stainless steel with cold sprayed barrier coating under combined cyclic loading

Integration of metal additive manufacturing (AM) and cold spray (CS) technologies provide an unprecedented opportunity to manufacture coated material systems with complex geometrical features. The application of these material systems in functionally critical components requires adequate structural integrity, particularly in the presence of cyclic loading. This work researches the multiaxial fatigue (axial-torsional cyclic loading) behavior of a coated material system consisting of 15Cr-5Ni precipitation-hardening stainless steel (15-5 PH SS) substrate additively manufactured by direct metal laser sintering with a layer of chromium carbide nickel (CrC-Ni) barrier coating deposited by CS. The influence of AM and CS-induced residual stresses on fatigue performance of test specimens was thoroughly studied. Additionally, the effect of surface roughness and processes induced defects were considered to explain the crack growth mechanism. Stresses assessed by synchrotron X-ray diffraction indicated a substantial accumulation of residual stresses, particularly in the outer surface of the as-fabricated 15-5 PH SS specimens. The state of residual stress was changed notably following the deposition of CrC-Ni coating in the axial, hoop, and radial directions of the fatigue test specimen. Also, CS deposition of CrC-Ni coating caused significant improvement in the surface quality of the additively manufactured components. Fatigue test results indicated, CS deposition of CrC-Ni substantially enhances the fatigue life of the AM-produced 15-5 PH SS substrate in all loading conditions, particularly in the high cycle fatigue regime. The improvement in the fatigue life of the specimens with coating was associated with a reduction in equivalent residual stress at the substrate surface and improvement in the specimens' surface condition (i.e., reduced surface roughness). The fractographic analysis of the specimen indicated the cracks tend to initiate in the surface of both as-fabricated and cold-sprayed specimens. However, the mechanism of crack growth changed notably following the deposition of CrC-Ni coating. The cracks tended to propagate in the planes parallel or with a small deviation from the build layers of the AM-produced specimens. On the other hand, deposition of CrC-Ni coating increased the deviation of crack growth plane from the build layers of the substrate.

Pure copper components fabricated by cold spray (CS) and selective laser melting (SLM) technology

To study effect of the different metal additive manufacturing techniques on microstructural evolution, phase constitution and the relationship between the microstructure and tensile behavior of pure Cu parts, components were manufactured by selective laser melting (SLM) technology and cold spraying (CS) technology, respectively. The microstructure of Cu parts was detected using an optical microscope (OM) and scanning electron microscopy (SEM). The XRD spectrum revealed that only Cu phase is formed in the SLM Cu and CS Cu samples. The microstructure of the SLM Cu samples is constituted by the polycrystalline grains with substructures including the columnar dendrites and the equiaxed structures. As for the CS Cu samples, only the equiaxed grains were detected. In terms of the main physical properties, the averaged electrical conductivity of SLM Cu sample is 41% IACS, while that of CS Cu sample is 73% IACS. For the microhardness, the mean microhardness value of the CS Cu and the SLM Cu samples is 144.2 ± 4.3 HV0.05 and 83.6 ± 5.2 HV0.05, respectively. With regard to the statistic mechanical properties, the yield strength (YS) and ultimate tensile strength (UTS) of the SLM Cu part is approximately 185.8 ± 6.1 MPa and 242.2 ± 8.2 MPa, respectively.

Microstructure of Cross-Linked High Densification Network and Strengthening Mechanism in Cold-Sprayed Ti-6Al-4V Coating After Heat Treatment

In this study, Ti-6Al-4V (TC4) coating was prepared using an in situ shot peening-assisted cold spraying technology in which large shot peening particles were mixed with TC4 spraying powders to prepare the deposit. To improve its strength and toughness, the coating was heat-treated at 600-1000 °C in vacuum. The results demonstrated that the microstructure of the as-sprayed coating exhibited a special structure that was denser at the regions tamped by the shot peening particles and porous at the nontamped regions. When the coating was heat-treated at 800 and 1000 °C, the interface between the particles had largely disappeared and the local pores had interconnected with each other due to thermal diffusion and recrystallization. The coating hardness decreased slightly after annealing at 600 and 800 °C due to the released strain hardening effect. The bonding strength of the coating after annealing improved in comparison with that of the as-sprayed coating. The tensile strength of the coating improved significantly under annealing at 800 °C. A cross-linked high densification network was formed after annealing due to the effect of in situ shot peening, which served as a reinforced framework and enhanced the strength of the coating.

Preparation of Al-based amorphous coatings and their properties

Al86Ni8Co1La1Y2Gd2 amorphous coatings were prepared using cold gas kinetic spray technology. The results show that Al86Ni8Co1La1Y2Gd2 amorphous coatings are achieved with the porosity about 3.2%, thickness about 893 μm, the amount of amorphous phase about 82.5%, the hardness about 300HV0.2. The corrosion potential and anti-corrosion life of 7075 T6 alloy aluminum are about −0.78 V and 72 h, respectively. The electrochemical analysis and neutral salt spray are about −0.69 V corrosion potential and 274 h anti-corrosion life for amorphous Al-based coatings, respectively. Therefore, the life of the Al-based amorphous coatings is about 3.8 times that of 7075 T6 aluminum alloy. Besides, the failure mechanism was analyzed using TEM in this investigation. In a word, Al86Ni8Co1La1Y2Gd2 coatings keep dense structure, high amorphous content, favorable amorphous phase stabilizing ability and longer anti-corrosion life. That is, Al86Ni8Co1La1Y2Gd2 coatings have better comprehensive properties. Therefore, these findings indicate that the present Al86Ni8Co1La1Y2Gd2 amorphous coatings prepared using cold gas kinetic spray technique can protect aluminum alloy very well and they can be considered to be used in aviation field.

Mechanical reliability modification of metal matrix composite coatings by adding al particles via cold spray technology

Within biomedical applications, there is ever increasing research of lightweight, improved long-term performance, safe biocompatible and mechanical reliable bearing surfaces. Such efforts are being made to find materials with excellent mechanical properties able to meet the design requirements of medical implant applications, in order to manufacture competitive implant components. In this perspective, Cold Spray (CS) technology is used to deposit an oxygen sensitive material (e.g. Ti-6Al-4V & Al) and create a Ti-based Metal Matrix Composite (MMC) coating by the addition of Al particles. The microstructure of MMC coatings was modified, which subsequently changed the toughness of these coatings to reduce the susceptibility to crack. Surface roughness, coatings thickness, porosity and chemical composition results indicate that a CS deposition is a reliable and reproducible method to fabricate a MMC coating. The wear behaviour of this coating has been assessed and a higher amount of Al improves the coating's toughness through modification of hardness and wear resistance. This MMC coating could be a promising candidate that is being an undercoat in the damage tolerant coating system to ensure a reliable bearing surface for artificial joints with beneficial impact resilience and damage tolerance.

Intelligent design optimization of battery pack enclosure for electric vehicle by considering cold‐spraying as an additive manufacturing technology

AbstractVibrations shocks induced during working conditions cause stresses and deformations of the battery case parts and heating may cause fire, which affects vehicle safety. Hence, the battery case and its parts should be of better mechanical features and lightweight to make the vehicle more efficient and safer. To achieve all the requirements, cold spraying found to be the potential technology for additive manufacturing the parts with better conductivities and lesser porosities as compared to the parts produced by conventional methods. Therefore, this article has proposed a consideration of the cold spray technology to improve the mechanical performances of the battery casing, including maximizing the minimum natural frequency, and minimizing the maximum deformation. ANSYS Workbench has been used for finite element modeling of battery pack enclosures. The model of the battery pack enclosures has been analyzed by obtaining the natural frequencies of the order 10. Further, static analysis has been performed to get the maximum deformation. Finally, a parametric model has been established and multiobjective optimization has been performed. The results obtained with the cold sprayed process show that the value of maximum deformation is being lowered by 59.49% and has a much higher value of natural frequency than that obtained with conventional methods.

Corrosion behavior of Al2O3-reinforced graphene encapsulated Al composite coating fabricated by low pressure cold spraying

A series of novel graphene (G) encapsulated Al coatings with different G content reinforced by Al2O3 were deposited on AZ31B Mg alloy via low pressure cold spraying technology. Their structure and corrosion characteristics were evaluated. The results indicated that in-situ reduction method could be used to reduce graphene oxide (GO) to G coated on the surface of Al powders. The obtained G encapsulated Al powders could be deposited to form a protective coating on Mg alloy by low pressure cold spraying. In the cold sprayed coatings, the plastic deformation of the Al/G particles is more severe than that of the pure Al particles. The cold sprayed Al/G coating behaves more compact structure than the cold sprayed Al coating. The cold sprayed Al/G coating has well corrosion resistance and stronger re-passivation capacity due to its longitudinally accelerated pitting corrosion mechanism changed to tangential superficial corrosion by graphene.

Design and analysis of additive manufactured bimodal structures obtained by cold spray deposition

Additive manufacturing potential of cold spray technology was used to fabricate freestanding samples of a copper alloy. Different volume fractions of micro and nanocrystalline powder particles were used to obatin a bimodal structure with heterogeneous arrangement of crystalline phases. The effects of volume fractions of each phase were investigated on the microstructural arrangement, porosity, microhardness, residual stresses, and mechanical strength of the deposited materials. A series of finite element simulations were developed and validated by experimental data to describe the influence of volume fraction, morphology, and spatial distribution of the phases on the global strength of the samples under tensile loading. The obtained results evidence the possibility of tailoring the mechanical response of freestanding cold spray deposits, adopting a heterogeneous phase structure. Optimized fabrication parameters and post-processing strategies should be studied to further enhance the performance of the designed bimodal materials and overcome the intrinsic brittleness of cold spray deposits.

Overview of cold spray coatings applications and comparisons: a critical review

PurposeThis 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/approachA 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.FindingsFrom 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/valueCold 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.

An Overview of Cold Spray Additive Technology in Australia for Melt-less Manufacture of Titanium

The difficulty in significantly reducing the cost of titanium products is partly related to the high cost of manufacturing. This includes additive manufacturing; e.g. Electron Beam Melting (EBM) and Selective Laser Melting (SLM), as well as traditional approaches that are based on a melting process. In particular, the cost of titanium powder has placed limits on the application of additive manufacturing approaches that involve melting to broader commercial applications beyond military, aerospace and implants. More than a decade ago, Australia adopted cold spray technology as a meltless additive manufacturing technique to fabricate titanium through a strategic initiative at Commonwealth Scientific and Industrial Research Organisation (CSIRO). The high deposition rate, ~100 times faster than the other additive technologies, and the solid state deposition were amongst the rationales for investment in cold spray technology. A combination of carefully designed experiments and sophisticated 3D models were developed to assess performance of the current industrial-scale cold spray systems for commercial clients. The success and challenges of this solid state deposition technology will be detailed with a focus on real industrial impact. The future development of melt-less titanium manufacturing using cold spray will be discussed with consideration of commercial and environmental benefits.

Highly efficient compact cold spray system for in-situ repairing of stainless steel material components

Cold Spray (CS) technology enables structural reinforcement, coating and repairing of metal-based components. The deposition occurs by the impact of small particles accelerated at supersonic velocity on the deposition surface. While processing stainless steel material the CS must be run in high-pressure conditions, thus making any in-situ repairing prohibitive and risky. This paper presents a novel CS deposition method to coat stainless steel with a compact and transportable system infrastructure. The final part of the paper shows the advantages of the proposed CS deposition system against existing methods, in relation to industrial coating applications.

Development of palladium nanoparticles deposition on a copper substrate using a molecular dynamic (MD) simulation: a cold gas dynamic spray process

The objective of this study is to create an ultra-thin palladium foil with a molecular dynamic (MD) simulation technique on a copper substrate surface. The layer formed onto the surface consists of a singular 3D palladium (Pd) nanoparticle structure which, by the cold gas dynamic spray (CGDS) technique, is especially incorporated into the low-cost copper substrate. Pd and Cu have been chosen for their possible hydrogen separation technology applications. The nanoparticles were deposited to the substrate surface with an initial velocity ranging from 500 to 1500 m/s. The particle radius was 1 to 4 nm and an angle of impact of 90° at room temperature of 300 K, in order to evaluate changes in the conduct of deformation caused by effects of size. The deformation mechanisms study revealed that the particle and substrate interface is subject to the interfacial jet formation and adiabatic softening resulting in a uniform layering. However, shear instabilities at high impact speeds were confirmed by the evolution of von Mises shear strain, temperature evolution and plastic strain. The results of this study can be used to further our existing knowledge in the complex spraying processes of cold gas dynamic spray technology.

The role of PVD sputtered PTFE and Al2O3 thin films in the development of damage tolerant coating systems

The surfaces of artificial joints are susceptible to premature wear which reduces their service life leading to the increased risk of revision arthroplasty. Tribological coatings having low coefficients of friction (CoF) and which are also biocompatible are therefore required to minimise such risks.Metal matrix composite (MMC) coatings exhibiting a modified toughness structure, thus reducing the potential to crack were successfully fabricated by cold spray (CS) technology. The coatings comprised of an ultra-low wear polytetrafluoroethylene (PTFE)+alumina (Al2O3) composite, firstly delineated by Burris and Sawyer in 2006, were prepared on cold sprayed substrate and the functionality of such coatings in terms of enhanced frictional properties was investigated.In this study, PTFE+Al2O3 thin film coatings were prepared by physical vapour deposition (PVD) and incorporated with cold sprayed MMC coatings to produce a damage tolerant coating system designed to extend the service life of artificial movable joint surfaces.Surface characterisation analysis indicated the formation of a PTFE–Al2O3 nanocomposite forming between the PTFE and Al2O3. This composite thin film exhibited excellent friction reducing ability up to an applied load of 7N. Regardless of whether the Ti–6Al is manufactured by a layer-by-layer approach or co-sputtering method, the CoF is reduced to below 0.1 at the start of the test. Furthermore, the results reveal that the PVD sputtered PTFE+Al2O3 thin film functionalises the cold sprayed surface by offering a self-lubricating effect and that PVD combined with CS is reliable for devising material systems operating in high-wear applications.