From Particle Acceleration to Impact and Bonding in Cold Spraying

Schmidt, Tobias; Assadi, H.; Gärtner, F.; Richter, H.J.; Stoltenhoff, T.; Kreye, H.; Klassen, Thomas

doi:10.1007/s11666-009-9357-7

Cited by 489 publications

(221 citation statements)

References 19 publications

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“…In the impact of spherical objects -be it a 20-mm ball or a 20-µm particle -such a condition exists at the centre of the contact zone, where the interacting surfaces are almost parallel. It should be noted that bonding may also occur at the central zone due to frictional dissipation in angular impact [70], but this is not a common feature in CS. Figure 17.…”

Section: Bonding Of Single Microparticlesmentioning

confidence: 99%

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Cold spraying – A materials perspective

et al. 2016

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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. IntroductionCold spraying (CS) is a solid-state material deposition technique, where micron-sized particles of a powder bond to a substrate as a result of high-velocity impact and the associated severe plastic deformation. Acceleration of particles to high velocities is obtained via expansion of a pressurised and (ironically) 'hot' gas through a diverging-converging nozzle.Despite heating the process gas -which is to provide higher acceleration of the gas and also to facilitate particle deformation through thermal softening -the feedstock remains in the solid state throughout the entire process; hence the name 'cold' spraying. This is to underline the contrast to conventional thermal spraying where particles are completely or partially molten upon impact onto the substrate. Alternative terminology includes cold gas spray, micro cold spray, cold gas dynamic spray, kinetic spray, supersonic particle deposition and metal powder application (MPA), all of which refer to the same principle of solid-state powder deposition as described above. CS is used for coating and repair. It is also used for additive manufacturing (AM) at relatively high deposition rates as compared to the methods based on selective laser or electron beam melting. The main advantage of CS is that it alleviates the problems associated with high temperature processing of materials, such as oxidation and unfavourable structural changes. It is possibly the only continuous method to produce bulk components of metastable materials that are available only in the powder form, e.g. as obtained from mechanical attrition or gas atomisation. The aim of the present paper is to provide an overview of CS from a materials perspective, particularly for a broader audience in materials research, e.g. with interest in dynamic phenomena, plasticity and phase transformations. In terms of application and properties, CS is perhaps best to be compared to thermal spraying processes, as in [24,25]. In view of relevant physical phenomena, however, CS is mos...

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Section: Bonding Of Single Microparticlesmentioning

confidence: 99%

“…The table excludes the work on metallic glasses, which are discussed separately below. [24,70,107,[183][184][185] Early studies, reference material Nanocrystals Electrodes…”

Section: Metallic Materialsmentioning

confidence: 99%

Cold spraying – A materials perspective

et al. 2016

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“…It is well known that material deposition in cold spray results from high-velocity impact and subsequent deformation of particles (Ref [2][3][4][5][6][7][8][9]. The resulting adiabatic shear instabilities provide sufficient material flow and heat for bonding at the interface between particle and substrate.…”

Section: Introductionmentioning

confidence: 99%

“…The present analysis moves forward by considering the effect of various factors on v cr . Moreover, the seemingly complicated effect of process conditions on final properties of the deposit is reduced into simple relationships in view of the existing experimental data (Ref 8,9,19,(22)(23)(24)(25). To facilitate the analysis, v pi and v cr are expressed explicitly in terms of primary key parameters, namely, the particle size and the process gas pressure and temperature.…”

Section: Introductionmentioning

confidence: 99%

On Parameter Selection in Cold Spraying

et al. 2011

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For cold spraying, a method for the construction of the window of deposition and the selection of optimum process parameters is presented. Initially, particle impact velocity and the critical particle velocity for bonding are worked out and expressed explicitly in terms of key process and material parameters. Subsequently, the influence of particle velocity on coating characteristics is examined in view of the results of experiments and simulations. It has been found that main coating characteristics can be described as a unique function of the ratio of particle velocity to critical velocity, here referred to as g. Finally, coating properties are linked directly to primary process parameters via parameter selection maps, where contours of constant g are plotted on a plane of gas temperature versus gas pressure. Inferences of the presented method and the resulting parameter selection maps are discussed for the example of copper as feedstock material.

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“…Since the impact process takes place in a short period of time, heat cannot distribute equally throughout the particle and the substrate, resulting in localized heating. Consequently, this localized heating causes temperature rises at the interface of the particle/substrate or particle/particle [42]. From Figure 2.10 it can be seen that for impact velocities greater than 400 m/s a sudden jump in the interface temperature takes place.…”

Section: Particle Deformation and Bonding Mechanismmentioning

confidence: 98%

Influence of Alumina Addition to Aluminum Fins for Compact Heat Exchangers Produced by Cold Spray Additive Manufacturing

et al. 2015

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Aluminum and aluminum-alumina powder mixtures were used to produce pyramidal fin arrays on aluminum substrates using cold spray as an additive manufacturing process. Using aluminum-alumina mixtures instead of pure aluminum powder could be seen as a costeffective measure, preventing nozzle clogging. The fin geometries that were produced were observed using a 3D digital microscope to determine the flow passages width and fins geometric details. Heat transfer and pressure tests were carried out using different ranges of appropriate Reynolds numbers for the sought commercial application to compare each fin array and determine the effect of alumina content. It was found that the presence of alumina reduces the fins' performance when compared to pure aluminum but that they still outperform traditional fins. Numerical simulations were performed and were used to explain

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From Particle Acceleration to Impact and Bonding in Cold Spraying

Cited by 489 publications

References 19 publications

Cold spraying – A materials perspective

Cold spraying – A materials perspective

On Parameter Selection in Cold Spraying

Influence of Alumina Addition to Aluminum Fins for Compact Heat Exchangers Produced by Cold Spray Additive Manufacturing

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