scholarly journals Cold-Sprayed Al6061 Coatings: Online Spray Monitoring and Influence of Process Parameters on Coating Properties

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 348 ◽  
Author(s):  
Heli Koivuluoto ◽  
Jussi Larjo ◽  
Danilo Marini ◽  
Giovanni Pulci ◽  
Francesco Marra
Keyword(s):  
Cold Spray ◽  
Process Parameters ◽  
Cold Spraying ◽  
Deposition Efficiency ◽  
Particle Deformation ◽  
Influence Of Process Parameters ◽  
High Particle ◽  
High Kinetic Energy ◽  
Spray Processing ◽  
Particle Velocities

Process optimization and quality control are important issues in cold spraying and coating development. Because the cold spray processing is based on high kinetic energy by high particle velocities, online spray monitoring of particle inflight properties can be used as an assisting process tool. Particle velocities, their positions in the spray jet, and particle size measurements give valuable information about spraying conditions. This, in turn, improves reproducibility and reliability of coating production. This study focuses on cold spraying of Al6061 material and the connections between particle inflight properties and coating characteristics such as structures and mechanical properties. Furthermore, novel 2D velocity scan maps done with the HW CS2 online spray monitoring system are presented as an advantageous powder and spray condition controlling tool. Cold spray processing conditions were similar using different process parameters, confirmed with the online spray monitoring prior to coating production. Higher particle velocities led to higher particle deformation and thus, higher coating quality, denser structures, and improved adhesions. Also, deposition efficiency increased significantly by using higher particle velocities.

Structures and Properties of Laser-Assisted Cold-Sprayed Aluminum Coatings

2016 ◽  
Vol 879 ◽  
pp. 984-989 ◽  
Author(s):  
Heli Koivuluoto ◽  
Andrea Milanti ◽  
Giovanni Bolelli ◽  
Jyrki Latokartano ◽  
Francesco Marra ◽  
...  
Keyword(s):  
Cold Spray ◽  
Cold Spraying ◽  
Cost Effective ◽  
Deposition Efficiency ◽  
Solid Particles ◽  
Aluminum Coatings ◽  
Spray Process ◽  
Structures And Properties ◽  
High Kinetic Energy ◽  
Laser Heated

In the cold spray process, solid particles impact on a surface with high kinetic energy, deform plastically and form a coating. This enables the formation of pure and dense coating structures. Even more, coating performance and deposition efficiency can be improved by assisting the process with a laser. Laser-assisted cold spraying (LACS) has shown its potential to improve coating properties compared with traditional cold spraying. In this study, coating quality improvement was obtained by using a co-axial laser spray (COLA) process which offers a new, cost-effective laser-assisted cold spray technique, for high-quality deposition and repair. In the COLA process, the sprayed surface is laser heated while particles hit the surface. This assists the better bonding between particles and substrate and leads to the formation of tight coating structures. This study focuses on the evaluation of the microstructural characteristics and mechanical properties (e.g., hardness and bond strength) of LACS metallic coatings.

Parametric Redesign of a Convergent-Divergent Cold Spray Nozzle

2021 ◽  
Author(s):  
Florentina-Luiza Zavalan ◽  
Aldo Rona
Keyword(s):  
Cold Spray ◽  
Gas Flow ◽  
High Hardness ◽  
Cold Spraying ◽  
Spray Nozzle ◽  
Industry Standard ◽  
Particle Velocities ◽  
Radial Spread ◽  
Cold Metal ◽  
Carrier Gas Flow

Abstract The generation of a high velocity carrier gas flow for cold metal particle applications is addressed; with specific focus on titanium cold spraying. The high hardness of this material makes cold spraying titanium difficult to achieve by industry standard nozzles. The redesign of a commercial conical convergent-divergent cold spray nozzle is achieved by the application of aerospace design codes; based on the Method of Characteristics; towards producing a more isentropic expansion by contouring the nozzle walls. Steady threedimensional RANS SST k-ω simulations of nitrogen are coupled two-way to particle parcel tracking in the Lagrangian frame of reference. The new contoured nozzle is found to produce higher particle velocities with greater radial spread; when operated at the same conditions/cost of operation as the commercial nozzle. These numerical results have shown the potential for extending cold spray to high density and low ductility particles by relatively minor rig modifications; through an effective synergy between gas dynamics and material science.

scholarly journals Influence of Cold Spray Nozzle Displacement Strategy on Microstructure and Mechanical Properties of Cu/SiC Composites Coating

2019 ◽  
Vol 813 ◽  
pp. 110-115
Author(s):  
Olga Matts ◽  
Hussein Hammoud ◽  
Alexey Sova ◽  
Zineb Bensaid ◽  
Guillaume Kermouche ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Cold Spray ◽  
Vertical Direction ◽  
Cold Spraying ◽  
Traverse Speed ◽  
Deformation Pattern ◽  
Spray Nozzle ◽  
Particle Deformation ◽  
Compressive Tests

In this work an influence of cold spray nozzle displacement parameters on the properties of copper-silicon carbide cold spray deposits is considered. In particular the influence of nozzle traverse speed and distance between deposited tracks on the coating porosity and behavior during compressive tests was analyzed. It was shown that cold spraying at low nozzle traverse speed leads to formation of thick tracks with quasi-triangular cross-section. As a consequence, the particle impact angle on the sides of spraying track increases that. Thus, the particle deformation at impact on the track periphery becomes insufficient and local porosity value rises. Increase of nozzle traverse speed allows increasing coating density and mechanical properties due to amelioration of particle deformation conditions. Compressive tests revealed significant anisotropy of mechanical properties of copper-silicon carbide cold spray deposits. In particular, compressive strength measured in vertical direction (perpendicular to the substrate) was significantly higher than one measured in horizontal plane (parallel to substrate). This anisotropy could be explained by the orientation of particle deformation pattern during impact.

Application of Laser Assisted Cold Spraying Process for Materials Deposition

2014 ◽  
pp. 177-221 ◽  
Author(s):  
Monnamme Tlotleng ◽  
Esther T. Akinlabi ◽  
Mukul Shukla ◽  
Sisa Pityana
Keyword(s):  
Cold Spray ◽  
Supersonic Nozzle ◽  
Cold Spraying ◽  
Hybrid Technique ◽  
X Ray Diffraction ◽  
Laser Engineered Net Shaping ◽  
Rapid Prototyping And Manufacturing ◽  
Particle Velocities ◽  
Net Shaping ◽  
Precursor Powders

The Laser-Assisted Cold Spraying (LACS) process is a hybrid technique that uses laser and cold spray mechanism to deposit solid powders on metal substrates. For bonding to occur, the particle velocities must be supersonic. The supersonic effects can be achieved by passing a highly compressed Nitrogen gas (˜30 bars) through de Laval supersonic nozzle. LACS is a surface coating technique that is desirable in rapid prototyping and manufacturing, particularly for biomedical applications. Current world research reveals that the capability of the LACS regarding the enhancement of surface properties of coating titanium alloys with hydroxyapatite will be essential for fabricating scaffolds for bone implants using Laser Engineered Net Shaping (LENS) technique. In this chapter, coatings of composite powders made of titanium and hydroxyapatite deposited on Ti-6Al-4V substrate by LACS technology are presented. These coatings were successfully characterised by means of X-Ray Diffraction (XRD) and optical microscopy for their phases, composition, and microstructure, respectively. The results of the produced LACS coatings compare well with those obtained with traditional thermal spray and cold spray techniques, respectively. In addition, the XRD results were found to be similar to the precursor powders, which indicated that no phase transformation occurred to HAP. Coatings comprising of other crystalline phases of HAP are less bio-integrable and fail quicker within the human body fluids environments.

Cold Spray Deposition of Heat-Treated Inconel 718 Powders

2021 ◽  
Author(s):  
Lorena Perez ◽  
Jake Colburn ◽  
Luke N. Brewer ◽  
Michael Renfro ◽  
Tim McKechnie
Keyword(s):  
Heat Treatment ◽  
Cold Spray ◽  
Inconel 718 ◽  
Deformation Behavior ◽  
Spray Deposition ◽  
High Strength ◽  
Particle Deformation ◽  
Delta Phase ◽  
High Particle ◽  
Heat Treated

Abstract In this work; Inconel 718 gas-atomized powder was successfully heat treated over the range of 700-900°C. As-atomized and as-heat treated powders were cold sprayed with both nitrogen and helium gasses. Cold spray of high strength materials is still challenging due to their resistance to particle deformation affecting the resulting deposit properties. Powder heat treatment to modify its deformation behavior has recently been developed for aluminum alloy powders; however; there is no literature reported for Inconel 718 powders. The microstructural evolution of the powder induced by the heat treatment was studied and correlated with their deformation behavior during the cold spray deposition. Deposits sprayed with heat-treated powders at 800 and 900 °C and nitrogen showed less particle deformation and higher porosity as compare to as-atomized deposit associated to the presence of delta phase in the powders precipitated by the heat treatment. In contrast; deposits sprayed with helium using both powder conditions; as-atomized and as heat-treated powders; showed high particle deformation and low porosity indicating that the type of gas has a greater effect on the particle deformation than the delta phase precipitated in the heat-treated powders. These results contribute to understanding the role of powder microstructure evolution induced by heat treatment on the cold spray deposits properties.

Adhesion Strength Improvement by Laser Surface Texturing of Metallic Repair Coatings Deposited by Cold Spraying

2021 ◽  
Author(s):  
R. Kromer ◽  
R.N. Raoelison ◽  
Y. Danlos ◽  
C. Verdy ◽  
S. Costil ◽  
...  
Keyword(s):  
Adhesion Strength ◽  
Pure Aluminum ◽  
Surface Texturing ◽  
Cold Spraying ◽  
Deposition Efficiency ◽  
Laser Surface ◽  
Laser Surface Texturing ◽  
Textured Surfaces ◽  
Particle Deformation ◽  
Spray Process

Abstract Cold spray process was chosen as a good candidate for dimensional restoration and protection of components. Commercially pure aluminum; aluminum-alloy or titanium were recommended for different applications. This paper investigates laser surface texturing association to enhance durability of sprayed coatings. Laser is easy automated; localized and reliable process. It was applied for prior-surface treatment. Textured surfaces were produced and compared to conventional treatments; such as grit-blasting; in terms of deposition efficiency and adhesion bond strength. Patterns promoted direct particle embedment. Particle-substrate interface exhibited significant temperature rate and strain in cavities. Intimate contacts and particle compressive states were assumed responsible for improvement. The particle deformation and bonding behaviors were evaluated and discussed for the different configurations. Thus; window of deposition was increased with laser surface texturing. Anchoring mechanisms increased two fold the adhesion strength compared to conventional pre-treatments. In one case; the interface was stronger than the coating cohesive strength.

Cold spraying and laser cladding as an alternative to electroplating processes

2019 ◽  
Vol 91 (2) ◽  
pp. 205-215 ◽  
Author(s):  
Jaroslaw Sienicki ◽  
Wojciech Zórawski ◽  
Adam Dworak ◽  
Piotr Koruba ◽  
Piotr Jurewicz ◽  
...  
Keyword(s):  
Cold Spray ◽  
Laser Cladding ◽  
Process Parameters ◽  
Process Development ◽  
Research Work ◽  
Cold Spraying ◽  
High Energy ◽  
Titanium Coating ◽  
Low Carbon ◽  
Content Type

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.

scholarly journals Characterization of mechanical behaviour of aluminum powders under fast dynamic conditions

2021 ◽  
Vol 250 ◽  
pp. 01036
Author(s):  
Francesco Delloro ◽  
Hugo Durand ◽  
Laurent Lacourt ◽  
Jean-Christophe Teissedre ◽  
Alain Thorel ◽  
...  
Keyword(s):  
Cold Spray ◽  
Mechanical Behaviour ◽  
Bulk Material ◽  
Laser Shock ◽  
Correct Process ◽  
Static Compression ◽  
Aluminum Powders ◽  
High Particle ◽  
Particle Velocities

Cold spray is a process belonging to the thermal spray family, characterized by relatively low temperatures and high particle velocities. Upon impact, particles undergo large plastic deformation at solid state in dynamic regime up to 109 s-1. The knowledge of powder behaviour in such conditions is essential to catch key phenomena in cold spray and a necessary step for a correct process modelling. However, little is known on mechanical behaviour of feed-stock powders when submitted to cold spray conditions. In this study, an approach focused on single particles combining laser shock induced impact, namely LASHPOL (LAser SHock POwder Launcher), and quasi-static compression was therefore developed. This method was applied in this study on spherical Aluminium powders but can work with any other powder material. The mechanical behaviour of powders was characterized and used to fit the parameters of Johnson-Cook constitutive model, by means of finite element inverse method. The combination of static and dynamic tests resulted in an original characterization of powder, which revealed having a different mechanical behaviour than the corresponding bulk material.

scholarly journals Cold Spray of Metallic Coatings on Polymer Based Composites for the Lightning Strike Protection of Airplane Structures

2021 ◽  
Author(s):  
F. Delloro ◽  
A. Chebbi ◽  
H. Perrin ◽  
G. Ezo’o ◽  
A. Bastien ◽  
...  
Keyword(s):  
Cold Spray ◽  
Composite Structures ◽  
Spray Deposition ◽  
Substrate Surface ◽  
Cold Spraying ◽  
Deposition Efficiency ◽  
Lightning Strike ◽  
Thin Polymer Film ◽  
Metallic Coatings ◽  
Metallic Particles

Abstract Unlike their metal counterparts; composite structures do not readily conduct away the electrical currents generated by lightning strikes. Cost reduction and expected production growth of the next middle range airplanes require automated manufacturing process of polymer components. The development of an automated technology to metallize polymer based composite for lightning strike protection is the aim of the CO3 project (EU Grant agreement: ID831979). In this study; thermal and electrical conductivities of composites were achieved by cold spray deposition of Cu or Al coatings. Critical points to be addressed were substrate erosion during cold spray; lack of polymer-metal adhesion and poor deposition efficiency. Several strategies were tested: i) a thin polymer film was cocured at the substrate surface before cold spraying; to enable implantation of metallic particles in the film; helping coating build-up and protecting the fibers of the composite. ii) Cold spraying a mix of metal and polymer powders to improve coating adhesion and prevent fiber damage. iii) Supercritical Nitrogen Deposition technology; prior to cold spray; to mechanically anchor metallic particles into the polymer. Subsequent cold spraying of purely metallic coatings was more efficient and showed better adhesion. All coatings were tested in terms of adhesion strength and electrical conductivity.

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