Issue 22

H. Singh et alii, Frattura ed Integrità Strutturale, 22 (2012) 69-8 4; DOI: 10.3221/IGF-ESIS.22.08 69 Cold spray technology: future of coating deposition processes Harminder Singh Guru Nanak Dev University, Regional Campus, Jalandhar, Punjab-144007, India harminder10@gmail.com T.S. Sidhu Shaheed Bhagat Singh College of Engg. & Tech., Ferozepur, Punjab, India S.B.S. Kalsi Amritsar College of Engineering & Technology, Amritsar, Punjab, India A BSTRACT . Cold spray (CS) belongs to a wide family of thermal spray technology with the difference that it is a solid state process in which spray particles are deposited via supersonic velocity impact at a temperature much below the melting point of the spray material. This paper briefly describes the various aspects of this rapidly emerging technology, with almost all the important parameters which affect the deposition behavior along with advantages and limitations; applications and history of emergence of this process is also reviewed. Though this technology emerges three decades ago but still it could not establish itself as viable practical industrial technology. Hence, the efforts, along with funding from public/private sources are required to commercialize this coating process. It is expected that next decade will saw the growth of cold spray as a viable coating process around the globe. K EYWORDS . Cold Spray; Thermal Spray; Coating; Corrosion. I NTRODUCTION old Spray(CS) is a relatively recent spray technology which falls under the larger family of thermal spray processes[1], and there are different approaches known by different names such as: Cold Gas Dynamic Spraying, Kinetic Spraying, High Velocity Particle Consolidation (HVPC), High Velocity Powder Deposition and Supersonic Particle/Powder Deposition (SPD). The basic principle of the cold spray process is very simple: A high velocity (300 to 1200 m/s) gas jet, formed using a deLaval or similar converging/diverging nozzle, is used to accelerate powder particles (1 to 50 µm) and spray them onto a substrate, located approximately 25 mm from the exit of the nozzle. where they impact and form a coating. The kinetic energy of the particles rather than high temperature, helps these particles to plastically deform on impact and form splats, which bond together to produce coatings and thereby avoids or minimizes many deleterious shortcomings of traditional thermal spray methods such as high-temperature oxidation, evaporation, melting, crystallization, residual stresses, gas release. In this process, powder particles are accelerated by the supersonic gas jet at a temperature that is always lower than the melting point of the material, resulting in coating formation from particles in the solid state and hence no melting and solidification process is experienced by the powders like in traditional thermal spray process [2, 3]. C