A comparative review on cold gas dynamic spraying processes and technologies
- Authors: Oyinbo, Sunday Temitope , Jen, Tien-Chien
- Date: 2020
- Subjects: Cold gas dynamic spraying , Spraying parameters , Deformatiom mechanism
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/436831 , uj:37907 , Citation: Oyinbo, S.T. & Jen, T.C. 2020. A comparative review on cold gas dynamic spraying processes and technologies. , DOI: https://doi.org/10.1051/mfreview/2019023
- Description: Abstract: Cold gas dynamic spraying (CGDS) is a relatively new technology of cold spraying techniques that uses converging-diverging (De Laval) nozzle at a supersonic velocity to accelerate different solid powders towards a substrate where it plastically deforms on the substrate. This deformation results in adhesion to the surface. Several materials with viable deposition capability have been processed through cold spraying, including metals, ceramics, composite materials, and polymers, thereby creating a wide range of opportunities towards harnessing various properties. CGDS is one of the innovative cold spraying processes with fast-growing scientific interests and industrial applications in the field of aerospace, automotive and biotechnology, over the past years. Cold gas spraying with a wide range of materials offers corrosion protection and results in increases in mechanical durability and wear resistance. It creates components with different thermal and electrical conductivities than that substrates would yield, or produces coatings on the substrate components as thermal insulators and high fatigue-strength coatings, and for clearance control, restoration and repairing, or prostheses with improved wear, and produces components with attractive appearances. This review extensively exploits the latest developments in the experimental analysis of CGDS processes. Cold gas dynamic spraying system, coating formation and deposit development, description of process parameter and principles, are summarized. Industrial applications and prospectives of CGDS in future research are also commented.
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Numerical investigations on cold gas dynamic spray process with nano- and microsize particles
- Authors: Jen, Tien-Chien , Li, Longjian , Cui, Wenzhi , Chen, Qinghua , Zhang, Xinming
- Date: 2005
- Subjects: Numerical simulation , Cold gas dynamic spraying , Microparticles , Copper particles , Platinum particles
- Type: Article
- Identifier: uj:5265 , http://hdl.handle.net/10210/14934
- Description: The particle velocity in cold gas dynamic spraying (CGDS) is one of the most important factors that can determine the properties of the bonding to the substrate. In this paper, the acceleration process of microscale and sub-microscale copper (Cu) and platinum (Pt) particles inside and outside De-Laval-Type nozzle is investigated. A numerical simulation is performed for the gas-particle two phase flow with particle diameter ranging from 100 nm to 50 lm, which are accelerated by carrier gas nitrogen and helium in a supersonic De-Laval-type nozzle. The carrier gas velocity and pressure distributions in the nozzle and outside the nozzle are illustrated. The centerline velocity for two types of particles, Pt and Cu, are demonstrated. It is observed that the existence of the bow shocks near the substrate prevents the smaller size particles (less than 0.5 lm) from penetrating, thus leads to poor coating in the actual practices. Furthermore, the extended straight section may have different optimal length for different size particles, and even may be unnecessary for sub-microsize particles.
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The acceleration of charged nano-particles in gas stream of supersonic de-laval-type nozzle coupled with static electric field
- Authors: Jen, Tien-Chien , Pan, Liang-Ming , Li, Longjian , Chen, Qing-hua , Cui, Wenzhi
- Date: 2006
- Subjects: Static electric potential , Bow shock , Electrostatic-force-assisted cold gas dynamic spray , Cold gas dynamic spraying , Nano-particles
- Type: Article
- Identifier: uj:5269 , http://hdl.handle.net/10210/14938
- Description: This paper presents a numerical analysis of an innovative method for nano-scale particle deposition, called Electrostatic-forceassisted cold gas dynamic spray (ECGDS). The transport characteristics of nano-scale charged particles in supersonic gas stream coupled with electrostatic field are simulated. Outside the nozzle, there exists bow shock near the substrate, which causes steep pressure increase across the shock. When the gas flow penetrates the bow shock and approaches to the substrate, the carrier gas speed decreases to nearly zero. In this study, electrostatic force is used to assist the charged particle to achieve high velocity upon impact of the substrate. The effect of electrostatic field to the velocity distribution of charged particles is investigated. It is found that smaller particles have the higher impact velocities on substrate. The higher particle charge densities can lead to higher particle impact velocities; and the closer the particles approach to the substrate, the stronger the electrostatic forces act on particles. For nano-scale particles the particle density (i.e. different materials) almost has no influence on the velocity profile.
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