Use of Hot Hydrocarbons in a Plasma Installation for Application of Wear-Resistant Coatings

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Vol. 61, No. 4, November, 2020

USE OF HOT HYDROCARBONS IN A PLASMA INSTALLATION FOR APPLICATION OF WEAR-RESISTANT COATINGS I. N. Kravchenko,1,2,4 S. V. Kartsev,2 and Yu. A. Kuznetsov3 Translated from Novye Ogneupory, No. 7, pp. 51 – 56, July, 2020.

Original article submitted July 2, 2020. Results of comprehensive research on the use of exhaust gases from an internal combustion engine (ICE) as the source of hot hydrocarbons instead of propane-butane or natural gas to reduce oxidative processes are presented. Introduction of hot hydrocarbons in exhaust gases from an ICE is shown to reduce significantly the redox potential of a plasma-torch plasma jet with respect to the sprayed material. An experimental mobile multifunctional plasma installation is developed and enables air-plasma spraying and melting of applied wear-resistant coatings. In this case, the exhaust gases from an ICE are used as the plasma-forming gas. Keywords: hot hydrocarbons, internal combustion engine, plasma installation, plasma torch, resource-saving technologies, plasma spraying of coatings.

create strongly oxidizing conditions in a plasma torch that can oxidize practically all metals except for noble ones and create unfavorable conditions for applying various coatings. Therefore, mainly Ni-based self-fluxing alloys are used during operation of mobile multifunctional plasma installations with compressed air to apply wear-resistant coatings. This restricts considerably the scope of their use. Research was conducted to eliminate these drawbacks. The goal was to justify the use of hot hydrocarbons from an internal combustion engine (ICE) instead of propane-butane or natural gas during operation of mobile multifunctional plasma installations and to develop a method for protecting plasma melting by a gas-powder jet.

INTRODUCTION Highly effective resource-conserving technologies have acquired more significance in the fierce competitive battle now facing Russian manufacturers. Plasma methods for applying coatings is one of them [1 – 8]. Modern plasma technologies can produce high-quality metals and alloys, grow single crystals, cut and melt metals, apply wear-resistant coatings, and improve metal properties [9 – 13]. Plasma generators, i.e., electrical gas-discharge devices for producing plasma that are called plasma torches [14 – 21], are used for these purposes. Plasma torches are designed to produce low-temperature plasmas (104 K) and include mobile multifunctional plasma installations [22 – 24]. The power of such a plasma torch is ~80 kW. A mixture of class 12 compressed air (GOST 17433) and propane-butane with compressed air as the transporting gas is used as the plasma-forming gas. A plasma torch can create neutral, reducing, or oxidizing conditions depending on which plasma-forming gas is used. In our instance, compressed air was used as the plasma-forming gas. Of course, pure air will 1 2 3 4

EXPERIMENTAL The stated goal was achieved by solving the problem of using hot hydrocarbons from an ICE as the gas simultaneously for transportation of