Recent Developments of Cold Spray Coating

A special issue of Coatings (ISSN 2079-6412).

Deadline for manuscript submissions: closed (15 November 2020) | Viewed by 13234

Special Issue Editor


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Guest Editor
Army Research Laboratory, Aberdeen Proving Ground, MD 21005-5201, USA
Interests: cold spray process; coating technology; corrosion protection; powder technology; heat treatment; failure analysis; additive manufacturing
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Special Issue Information

Dear Colleagues,

The scope of this Special Issue will be the properties and inspection of cold spray coatings and cold spray for dimensional restoration. Of interest are wear- and corrosion-resistant coatings, especially those that are designed for chrome- and nickel-plating replacement that may also serve as a means for dimensional restoration. There has been much progress in the optimization of material properties associated with cold spray coatings, and I would like to showcase novel coatings and superior properties. For example, adhesion of cold spray coatings has increased considerably, as well as ductility, density, and corrosion resistance. Many more engineering alloys have been successfully sprayed using the cold spray process, and numerous applications have been transitioned. Cold spray has emerged as a viable repair technique in the aerospace and automotive industries, for ships and submarines, and even in the petrochemical and medical industries.

In particular, the topics of interest include but are not limited to:

  • Chrome- and nickel-plating replacement and hard-faced coatings;
  • Corrosion coatings, antimicrobial coatings, EMI shielding;
  • Dimensional restoration of aerospace, automotive, and ship components;
  • Optimization of process parameters for superior performance;
  • Materials characterization of cold spray coatings;
  • Applications of cold spray;
  • Nondestructive inspection of cold spray coatings.
Dr. Victor K. Champagne
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Coatings is an international peer-reviewed open access monthly journal published by MDPI.

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Published Papers (4 papers)

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Research

26 pages, 8164 KiB  
Article
Particle Velocimetry, CFD, and the Role of Particle Sphericity in Cold Spray
by Ozan Çağatay Özdemir, Joseph Mitchell Conahan and Sinan Müftü
Coatings 2020, 10(12), 1254; https://doi.org/10.3390/coatings10121254 - 18 Dec 2020
Cited by 22 | Viewed by 3159
Abstract
Implementation of the cold spray (CS) technology in manufacturing and repair creates a demand for reliable quality control and process monitoring measures. In this regard, particle size and impact velocity are undoubtedly the most important control parameters in CS. Several in-flight measurement systems [...] Read more.
Implementation of the cold spray (CS) technology in manufacturing and repair creates a demand for reliable quality control and process monitoring measures. In this regard, particle size and impact velocity are undoubtedly the most important control parameters in CS. Several in-flight measurement systems for particle velocimetry are now available commercially for CS. These systems provide great potential to be used as a diagnostic tool for validating CS system performance in industrial applications. However, post processing the velocimetry data is required in many instances for achieving a complete understanding of the particle flow field. In this study, particle velocimetry is used in conjunction with computational fluid dynamics (CFD) simulations to: (i) identify the physical factors that dictate the particle velocity and its variability; (ii) develop high fidelity CFD models to accurately predict particle flight parameters that cannot be measured by available experimental tools; and (iii) present the capabilities of state-of-the-art velocimeters as a reliable diagnostic tool for measuring the consistency and repeatability of CS systems in manufacturing settings. In-flight particle size, location, and velocity are measured using a commercially available velocimeter for aluminum and copper particles sprayed with supersonic nozzles using helium, nitrogen, and air by two high pressure CS systems. As a result of this work, particle sphericity was clearly identified to have strong effects on particle velocity and to be one of the main factors of the variability of particle velocity. Furthermore, methods for building a high-fidelity 3D-CFD model was presented. CFD models were validated using particle velocimetry and schlieren imaging. Finally, particle velocimetry is shown to be a valid diagnostics tool for CS with systems capable of measuring in-flight particle velocities along with particle sizes. This article also outlines steps necessary for conducting cold spray process diagnostics repeatably and reliably. Full article
(This article belongs to the Special Issue Recent Developments of Cold Spray Coating)
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14 pages, 5123 KiB  
Article
Effect of WC-Ni Powder Composition and Preparation on Cold Spray Performance
by Joseph Heelan, Sean M. Langan, Caitlin Walde, Aaron Nardi, Matthew Siopis, Robert Barth, Timothy Landry and Aaron Birt
Coatings 2020, 10(12), 1196; https://doi.org/10.3390/coatings10121196 - 8 Dec 2020
Cited by 7 | Viewed by 2815
Abstract
Toxic metal reduction is at the forefront of many design considerations today; additive manufacturing has the ability to combine materials in ways other traditional processes cannot and has the potential to offer unique solutions to reduce hazardous materials needed in manufacturing. Tungsten carbide [...] Read more.
Toxic metal reduction is at the forefront of many design considerations today; additive manufacturing has the ability to combine materials in ways other traditional processes cannot and has the potential to offer unique solutions to reduce hazardous materials needed in manufacturing. Tungsten carbide (WC) has been used as a substitute in wear applications where toxic processes are traditionally utilized, but it can be difficult to deposit high-quality, hard and durable coatings. Additionally, there is a need to apply WC coatings on surfaces not feasible with the current processes. Cold spray, a solid-state directed powder deposition process, is effective at depositing carbides, though powders must be thoughtfully designed to achieve desired mechanical properties. In this study, WC was investigated as a hard chrome alternative for wear applications. Various blend ratios and preparation methods were evaluated as feedstock powder and then sprayed. Feedstock characteristics were compared to cold spray performance. Cold spray consolidations were evaluated for coating porosity and hardness. It was found that when powder make-up and composition were optimized, a high-hardness and low-porosity material was made that will contribute to the reduction in dependency of Cr in wear-facing components. Full article
(This article belongs to the Special Issue Recent Developments of Cold Spray Coating)
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28 pages, 9253 KiB  
Article
Rapidly Solidified Gas-Atomized Aluminum Alloys Compared with Conventionally Cast Counterparts: Implications for Cold Spray Materials Consolidation
by Bryer C. Sousa, Caitlin Walde, Victor K. Champagne, Jr., Jr., Aaron T. Nardi, Richard D. Sisson, Jr., Jr. and Danielle L. Cote
Coatings 2020, 10(11), 1035; https://doi.org/10.3390/coatings10111035 - 27 Oct 2020
Cited by 13 | Viewed by 3613
Abstract
In this work, three commercially available aluminum alloy systems (Al 2024, Al 6061, and Al 7075) were considered to explicitly capture the differences in material properties associated with a rapidly solidified, gas-atomized particulate feedstock as compared with their conventionally cast counterparts. Differences between [...] Read more.
In this work, three commercially available aluminum alloy systems (Al 2024, Al 6061, and Al 7075) were considered to explicitly capture the differences in material properties associated with a rapidly solidified, gas-atomized particulate feedstock as compared with their conventionally cast counterparts. Differences between the microstructural, thermodynamic, mechanical, and kinetic behaviors associated with gas-atomized and conventionally bulk counterparts have been tacitly assumed by the cold spray community. However, many researchers continue to utilize legacy properties from bulk materials when simulating particle impact phenomena in silico, for example. By way of recognizing the fact that bulk material properties may not serve as substitutes for gas-atomized powder property input parameters for cold spray process simulation and computation in silico, enhanced cold spray research and development will be more easily achieved. Therefore, understanding the feedstock powder characteristics for use in cold spray can lead to fine-tuning the properties of cold spray consolidations. Optical microscopy, scanning electron microscopy, nanoindentation, microhardness, differential scanning calorimetry, elemental analysis, and cooling rate calculations were utilized. This work confirms preliminary findings that powder alloys may not be treated the same way as their bulk counterparts in so far as the enactment of heat treatment processing parameters are concerned. Specifically, vast discrepancies were found in the grain size, secondary phases, and mechanical behavior between the powder and cast versions of each alloy. Full article
(This article belongs to the Special Issue Recent Developments of Cold Spray Coating)
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10 pages, 6746 KiB  
Article
Microstructural Characteristics in Babbitt Coatings Deposited by LPCS
by Wolfgang Tillmann, Leif Hagen, Mohamed Abdulgader, Mark Dennis Kensy and Michael Paulus
Coatings 2020, 10(7), 689; https://doi.org/10.3390/coatings10070689 - 17 Jul 2020
Cited by 4 | Viewed by 2577
Abstract
Studies have already established that the mechanical properties of Babbitt coatings significantly depend on the microstructural characteristics, such as the amount and distribution of intermetallic compounds dispersed in a soft solid solution matrix. For Sn–Sb–Cu-based Babbitt coatings, the formation of SbSn- and CuSn-based [...] Read more.
Studies have already established that the mechanical properties of Babbitt coatings significantly depend on the microstructural characteristics, such as the amount and distribution of intermetallic compounds dispersed in a soft solid solution matrix. For Sn–Sb–Cu-based Babbitt coatings, the formation of SbSn- and CuSn-based precipitates has a substantial influence on the resulting microhardness and thus determines the maximum load carrying capacity. Thermal spraying of Sn-based Babbitt coatings results in a relatively more refined structure of these precipitates than in common manufacturing processes, such as casting, due to the thermal processing conditions. This study aims to evaluate the effect of the temperature of the propellant gas and substrate temperature on the microstructural characteristics of Sn–Sb–Cu-based Babbitt coatings deposited by low pressure cold spraying (LPCS). The deposits were examined for their phase composition, microhardness and mesoscopic structure. It was found that the coatings were mainly composed of Sb2Sn23, Sb0.49Sn0.51 and Sorosite (CuSn or CuSb0.115Sn0.835), regardless of the substrate temperature or temperature of the propellant gas to be investigated. For a gas temperature above 300 °C, an increased microhardness was observed, which correlates with the appearance of a more homogenous distribution of Sb0.49Sn0.51 dispersed in a soft Sn-rich solid solution matrix. Full article
(This article belongs to the Special Issue Recent Developments of Cold Spray Coating)
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