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The paper presents an analysis of the heat transfer processes in electric arc plasma conditions between the powder material and the plasma jet in different convective states. The heat transfer processes in the plasma jet generated for coating deposition are considered based on varying the conditions for the jet–powder interaction. The formed coating deposited onto the substrate acts as an indicator of the heat transfer efficiency. The heat transfer between the plasma jet and the powder material is facilitated by the turbulent nature of the plasma jet. The presented calculation results demonstrate the influence of the plasma flow turbulence on the motion of the fine powder and heating of the generated jet at the outlet of the plasma torch. An analysis of the influence of plasma flow turbulence on the acceleration and heating of fine powder particles was carried out. The experimental results allowed for the determination of the effect of the plasma jet turbulence degree on the heat transfer processes between the plasma and fine powder: the technological efficiency of the device with varying parameters of the spraying process and the flow rates of the material supply and plasma-forming gas were presented. The values of the plasma-forming gas supply rate, the material supply rate, and the Reynolds number were obtained while the other process parameters were fixed. The research was carried out within the state assignment of the Ministry of Science and Higher Education of the Russian Federation (theme No. FSEG-2023-0012). [ABSTRACT FROM AUTHOR]

The number of research papers as well as of patents and patent applications on cold spray and cold spray related technologies has grown exponentially in the current decade. This rapid growth of activity brought a tremendous amount of information on this technology in a short period of time. The main motivation for this review is to summarize the rapidly expanding common knowledge on cold spray to help researchers and engineers already or soon to be involved for their future endeavors with this new technology. Cold spray is one of the various names for describing an all-solid-state coating process that uses a high-speed gas jet to accelerate powder particles toward a substrate where they plastically deform and consolidate upon impact. Cold gas dynamic spray, cold spray, kinetic spray, supersonic particle deposition, dynamic metallization or kinetic metallization are all terminologies found in the literature that designate the above-defined coating process. This review on cold spray technology is divided into two parts. In this article, Part I, patents and patent applications related to this process are reviewed, starting from the first few mentions of the idea at the beginning of the 20th century to its practical discovery in Russia in the 1980s and its subsequent occidental development and commercialization. The patent review encompasses Russian and USA patents and patent applications. Part II will review the scientific literature giving a general perspective of the current understanding and capability of this process. [ABSTRACT FROM AUTHOR]