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.

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.

Influence of Preliminary Heat Treatment and Ball Milling of Aluminum Powder on Cold Spray Process

2021 ◽  
Vol 313 ◽  
pp. 127-135
Author(s):  
S.V. Klinkov ◽  
V.F. Kosarev ◽  
A.E. Chesnokov ◽  
A.V. Smirnov ◽  
V.S. Shikalov
Keyword(s):  
Heat Treatment ◽  
Ball Milling ◽  
Aluminum Powder ◽  
Cold Spraying ◽  
Preliminary Heat Treatment ◽  
Aluminum Powders ◽  
Aluminum Coatings ◽  
Spray Process ◽  
Spraying Process ◽  
Milled Powders

This paper presents the results of a study of the effect of preliminary heat treatment and ball milling of aluminum powder on the cold spraying process and the properties of the obtained coatings (porosity and microhardness). The ball milling of aluminum powder leads to an increase in specific surface area, a decrease in apparent density and a decrease in the value of the crystallite size, which indicates a decrease in grain size. It is shown that coatings deposited from ball milled powders have slightly higher coatings hardness averagely. The profilometry of aluminum coatings obtained under the same conditions from the initial and processed powders did not reveal significant changes in the form of coatings and their typical dimensions (width, thickness), which indicates the absence of significant changes in the deposition coefficient of the initial and processed aluminum powders. Ball milled powders on average correspond to slightly higher hardnesses of coatings.

Cold Spray Processing of Titanium Powder

2000 ◽  
Author(s):  
J. Karthikeyan ◽  
C.M. Kay ◽  
J. Lindeman ◽  
R.S. Lima ◽  
C.C. Berndt
Keyword(s):  
Cold Spray ◽  
High Hardness ◽  
Deposition Efficiency ◽  
Hard Coatings ◽  
Nozzle Geometry ◽  
Maximum Effect ◽  
Vacuum Plasma Spray ◽  
Spray Process ◽  
Titanium Oxidation ◽  
Titanium Coatings

Abstract Oxygen-free titanium coatings are at present produced using vacuum plasma spray systems. The cold spray process can produce titanium coatings in atmospheric air at reduced cost. Variations of the deposition efficiency as well as the coating characteristics with various process parameters were studied. Results show that the deposition efficiency drops drastically below a critical temperature. The parameters which affect the jet velocity; viz., the type of gas and the nozzle geometry have maximum effect on the process deposition efficiency. Sprayed coatings were porous and exhibited a low modulus and high hardness. Post processing of the coating by machining produced dense, strong and hard coatings. Key words: Cold-Spray, Titanium, Oxidation.

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.

An Overview of Cold Spray Technique

2007 ◽  
Vol 561-565 ◽  
pp. 2419-2422 ◽  
Author(s):  
Niraj Bala ◽  
Harpreet Singh ◽  
S. Prakash
Keyword(s):  
Thermal Spray ◽  
Cold Spray ◽  
Developed Countries ◽  
Solid Particles ◽  
Cold Gas Dynamic Spraying ◽  
Future Research ◽  
Cold Spray Process ◽  
Spray Process ◽  
Spray Method ◽  
Spray Technique

The Cold spray or cold gas dynamic spraying is the new progressive step in the direction of development of high kinetic energy coating processes. The cold spray is a method for coating substrates under atmospheric conditions. In this process micron sized solid particles are accelerated and transported to substrates by means of supersonic free jets. Upon impacting the substrates, particles stick to the surface and form coatings which possess very low porosity. The paper outlines the principles involved in cold spray method and the equipment used for the technique. The cold spray method is related to classical thermal spray methods but it has some interesting additional features, which has been discussed in the paper. A fundamental feature of cold spray method i.e. concept of critical velocity along with the plausible mechanism theory responsible for the deposition of coating has been discussed briefly. Successful applications of cold spray process and its environment friendly aspect has been elaborated. It is reported that well founded cold spray technology will be able to compete for a good market share of VPS/PVD coatings in various fields like power, electronic/electrical, biotechnology, turbines and other industries. The cold spray process is still primarily in the research and development stage and only now becoming commercially available, and has been accepted as a new and novel thermal spray technique mainly in developed countries. The technology has great potential for future research especially with reference to its application to real industrial solution.

Study on Metal/Diamond Binary Composite Coatings by Cold Spray

2007 ◽  
Vol 534-536 ◽  
pp. 441-444 ◽  
Author(s):  
Hyung Jun Kim ◽  
D.H. Jung ◽  
J.H. Jang ◽  
Chang Hee Lee
Keyword(s):  
Cold Spray ◽  
Spray Deposition ◽  
Composite Coatings ◽  
Microstructural Characterization ◽  
Deposition Efficiency ◽  
Spray Process ◽  
Sprayed Coatings ◽  
Binary Composite

Metal/diamond binary composite coatings on Al substrate without grit blasting were deposited by cold spray process with in-situ powder preheating. Microstructural characterization of the as-sprayed coatings with different diamond size, strength and with/without Ti coating on diamond was carried out by OM and SEM. The assessment of basic properties such as tensile bond strength and hardness of the coatings, and the deposition efficiency was also carried out. Particular attention on the composite coatings was on the diamond fracture phenomenon during the cold spray deposition and the interface bonding between the diamond and the Fe-based metal matrix.

scholarly journals Structural Transformation and Mechanical Properties of Cold Sprayed Nickel Coatings after Annealing

2008 ◽  
Vol 1151 ◽  
Author(s):  
Yu Zou ◽  
Ahmad Rezaeian ◽  
Jerzy Szpunar ◽  
Eric Irissou ◽  
Stephen Yue
Keyword(s):  
Cold Spray ◽  
Structural Transformation ◽  
Large Strain ◽  
Cold Spraying ◽  
Coating Technology ◽  
Spray Process ◽  
Nickel Coatings ◽  
Electron Backscattering Diffraction ◽  
Continuous Recrystallization ◽  
Bond Interface

ABSTRACTCold spray is a relatively new coating technology in which coatings can be produced by powdered particles under large plastic deformation without significant heating. In this paper, nickel coatings were fabricated by cold spray process followed by heat treatment in inert gas. Structural transformation of both as-sprayed and annealed coatings was investigated by Electron Backscattering Diffraction (EBSD) in a FEG-SEM. The results show that after cold spraying sub-micron grains and subgrains with high crystal strain appear in the particle bond interface, but not shown in the center of particles. Microstructure was transformed to be uniform and stresses were released after annealing in 400°C for one hour. And ductility and formability were significantly improved due to recovery and recrystallization. Continuous recrystallization after large strain deformation could occur after cold spraying followed by annealing.

Investigation of Cold Sprayed NiCoCrAlY Bond Coating

2009 ◽  
Vol 79-82 ◽  
pp. 863-866 ◽  
Author(s):  
Xiang Bo Li
Keyword(s):  
Cold Spray ◽  
High Speed ◽  
Cold Spraying ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Bond Coating ◽  
Spray Process ◽  
High Speed Impact ◽  
Helium Gas

In this paper, NiCoCrAlY coating was deposited by cold spraying with helium gas under the temperature of 500°C and pressure of 2.6 MPa. The microstructure of the coating was characterized through surface morphology and cross-sectional microstructure by scanning electron microscopy and X-ray diffraction analysis. The results showed that the coating is deposited through intensive plastic deformation of the spray particles by high-speed impact, and no oxygen phenomena discovered in the cold spray process. We also detected the micro-hardness using the Digital Vickers Microhardness Tester. Result revealed that a compact texture and high micro-hardness NiCoCrAlY coating can be obtained by cold spray.

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