Deposition of multicomponent coatings by Cold Spray (original) (raw)
Related papers
Cold spraying: From process fundamentals towards advanced applications
Surface and Coatings Technology, 2015
Cold spraying (CS) is a relatively new material deposition technique based on the phenomenon of high-velocity particle/substrate impact. In this process, the powder is accelerated to supersonic speed in specially developed supersonic nozzles in which air, nitrogen or helium is usually employed as a powder carrier gas. In the absence of melting, oxidation and thermal decomposition of a particle in-flight during CS, the deposited coatings demonstrate low residual stresses and preserve the initial phase composition of the source material, which are important advantages for spraying temperature sensitive powders including nanostructures and nanocomposites. In the present paper the review in the field of development of cold spray technology is performed. Different scientific and technological aspects of CS such as surface activation, nozzle geometry, powder preheating, powder injection, control of spatial resolution of particle flux and proper selection of spraying parameters are discussed.
Cold spray technology: future of coating deposition processes
Cold spray (CS) belongs to a wide family of thermal spray technology with the difference that it is a solid state process in which spray particles are deposited via supersonic velocity impact at a temperature much below the melting point of the spray material. This paper briefly describes the various aspects of this rapidly emerging technology, with almost all the important parameters which affect the deposition behavior along with advantages and limitations; applications and history of emergence of this process is also reviewed. Though this technology emerges three decades ago but still it could not establish itself as viable practical industrial technology. Hence, the efforts, along with funding from public/private sources are required to commercialize this coating process. It is expected that next decade will saw the growth of cold spray as a viable coating process around the globe.
Influence of Feedstock in the Formation Mechanism of Cold-Sprayed Copper Coatings
Coatings
The aim of this article is to investigate the characterizations and formation mechanisms of cold-sprayed coatings using gas-atomized and electrolytic powders. The study highlights the importance of reaching the particles’ critical velocity for optimal deposition. The main findings reveal that the morphology and stacking conditions of the coatings have a significant impact on their mechanical properties. Coatings made with gas-atomized powders exhibited noticeable pores and higher plastic deformation, while electrolytic powder coatings had greater density and smoother interfaces with the substrate. Adhesion strength relied on the physical bonding resulting from the plastic deformation energy between the spraying powders and the substrate. Gas-atomized powders showed higher adhesion compared to electrolytic powders, with dendritic powders resulting in lower adhesion due to dispersed impact force. The interaction between thermal and kinetic energy during the cold spraying process facil...
Cold spray additive manufacturing of copper-based materials: Review and future directions
Materials Science in Additive Manufacturing
The cold gas dynamic spray process is a manufacturing process strategically designed for coatings. The conditions for the deposition of materials to form coatings have evolved over several decades. Copper and copper-based cold spray coatings are an interesting field for investigation, as it has substantial commercial demand and acceptance. Several important works have already been performed in this regard that shows the immense popularity of its applications in power industries. Cold gas dynamic spray, being an economic process, can produce coatings with superior quality and low oxidation. In this paper, a particular focus has been given to copper-based cold spray coatings along with their deposition parameters. The various mechanical, electrical, corrosion, and tribological properties of these copper-based cold spray coatings are commendable and economically lucrative. A good amount of experimental data has also been included in this review article to provide comprehensive informat...
Investigation of Al-Al2O3 Cold Spray Coating Formation and Properties
Journal of Thermal Spray Technology, 2007
Coating build-up mechanisms and properties of cold sprayed aluminum-alumina cermets were investigated. Two spherical aluminum powders having average diameters of 36 and 81 microns were compared. Those powders were blended with alumina at several concentrations. Coatings were produced using a commercial low pressure cold spray system. Powders and coatings were characterized by electronic microscopy and microhardness measurements. In-flight particle velocities were monitored for all powders. The deposition efficiency was measured for all experimental conditions. Coating performance and properties were investigated by performing bond strength test, abrasion test and corrosion tests, namely, salt spray and alternated immersion in salt water tests. These coating properties were correlated to the alumina fraction either in the starting powder or in the coating.
Cold spray coating: review of material systems and future perspectives
Surface Engineering, 2014
Cold gas dynamic spray or simply cold spray (CS) is a process in which solid powders are accelerated in a de Laval nozzle toward a substrate. If the impact velocity exceeds a threshold value, particles endure plastic deformation and adhere to the surface. Different materials such as metals, ceramics, composites and polymers can be deposited using CS, creating a wealth of interesting opportunities towards harvesting particular properties. CS is a novel and promising technology to obtain surface coating, offering several technological advantages over thermal spray since it utilizes kinetic rather than thermal energy for deposition. As a result, tensile residual stresses, oxidation and undesired chemical reactions can be avoided. Development of new material systems with enhanced properties covering a wide range of required functionalities of surfaces and interfaces, from internal combustion engines to biotechnology, brought forth new opportunities to the cold spraying with a rich variety of material combinations. As applications multiply, the total number of studies on this subject is expanding rapidly and it is worth summarizing the current state of knowledge. This review covers different material systems that have been studied up to now with an emphasis on potential innovative applications. This includes metallic, ceramic and metal matrix composite (MMC) coatings and their applications. Polymer (both as substrate and coating) and metal embedment in the polymer are also covered. CS has emerged as a promising process to deposit nanostructured materials without significantly altering their microstructure whereas many traditional consolidation processes do. Relevant material systems containing nanostructured powders are also considered. A critical discussion on the future of this technology is provided at the final part of the paper focusing on the microstructural bonding mechanisms for those relatively less explored material systems. These include MMCs involving more than one constituent, ceramics, polymers and nanostructured powders. Future investigations are suggested especially to quantitatively link the process parameters and the behaviour of the material systems of interest during impact.
Effect of Parameters to the Coating Formation during Cold Spray Process
Proceedings of the 3rd World Congress on Mechanical, Chemical, and Material Engineering, 2016
In this study, the effects of parameters such as substrate hardness, substrate surface roughness and stand-off distance to the coatings formation and properties of the coatings during cold spraying process were examined. For this purpose, coatings were deposited onto the copper substrate with using of commercially available copper powder. Substrate hardness of 55 HV, 107 HV and 140 HV were obtained by heat treatment and deformation hardening methods. Different substrate surface roughness was obtained by using of SiC emery papers which have different grits and stand-off distance during cold spray process was manipulated as 5, 10, 20 and 30 mm. After the production of the coatings, characterisation procedures were performed by microstructural observations which are optical and scanning electron microscope surveys, porosity concentrations, coating thickness and hardness measurement.
2007
The cold gas dynamic spray process developed in the middle of the 80’s reached the industrial stage in development. Even so, many scientific investigations still go on. The nature of the bond between the coating and the substrate is the subject of some controversy. The development of the process will be improved by understanding how the properties of the powder and the mechanical properties of the substrate influence the bonding process. This study analyses the basic dynamics of the process when copper is sprayed.• The one dimensional isentropic model of the gas behaviour in a Laval type nozzle allows evaluating the effect of the gas stagnation pressure P0 and temperature T0 on the impact velocity and temperature of the powder particle.• The analysis of single splats on two substrates (aluminium and steel) shows the influence of the substrate on the deformation of single particles and the influence of the impact speed on the impact shape.• Coatings are made of with powders with a sp...
Surface and Coatings Technology, 2006
This work describes recent progress in Cold Gas Dynamic Spraying process of conventional and nanocrystalline 2618 (Al-Cu-Mg-Fe-Ni) aluminum alloy containing Sc. As-atomized and cryomilled 2618 + Sc aluminum powders were sieved in two ranges of particle size (below 25 μm and between 25 and 38 μm), and sprayed onto aluminum substrates. The mechanical behavior of the powders and the coatings was studied using the nanoindentation technique, while the microstructure was analyzed using scanning and transmission electron microscopy. The influence of the powder microstructure, morphology and behavior during deposition on the coating properties was analyzed. It was concluded that the hard cryomilled particles do not experience extensive plastic deformation, and therefore failed to form a coating as dense as those produced using the gas-atomized spherical powder, despite the fact that the irregular shape cryomilled particles presented higher flight and impact velocities than the gas-atomized spherical particles. It was also observed that the influence of the particle morphology on the particle velocities is more pronounced for the larger particle size range (between 25 and 38 μm).
Cold spraying – A materials perspective
Acta Materialia, 2016
Cold spraying is a solid-state powder deposition process with several unique characteristics, allowing production of coatings or bulk components from a wide range of materials. The process has attracted much attention from academia and industry over the past two decades. The technical interest in cold spraying is twofold: first as a coating process for applications in surface technology, and second as a solid-state additive manufacturing process, offering an alternative to selective laser melting or electron beam melting methods. Moreover, cold spraying can be used to study materials behaviour under extremely high strain rates, high pressures and high cooling rates. The cold spraying process is thus considered to be relevant for various industrial applications, as well as for fundamental studies in materials science. This article aims to provide an overview of the cold spray process, the current understanding of the deposition mechanisms, and the related models and experiments, from a materials science perspective.