Optimization and Characterization of High Velocity Oxy-fuel Sprayed Coatings: Techniques, Materials, and Applications

Abstract

Abstract:In this work High Velocity Oxy-fuel (HVOF) thermal spray techniques, spraying process optimization, and characterization of coatings are reviewed. Different variants of the technology are described and the main differences in spray conditions in terms of particle kinetics and thermal energy are rationalized. Methods and tools for controlling the spray process are presented as well as their use in optimizing the coating process. It will be shown how the differences from the starting powder to the final coating formation affect the coating microstructure and performance. Typical properties of HVOF sprayed coatings and coating performance is described. Also development of testing methods used for the evaluation of coating properties and current status of standardization is presented. Short discussion of typical applications is done.

Innovation in the Process of Thermal Spraying Coatings

“…The presented and analyzed result showed that the coating obtained by hybrid spraying method had got the correct structure with a thickness of about 550 mm. Testing of micro-jet-cooled coatings, presented in this paper and in [2][3][4][5] showed substraty hardness and microporosity improvement over HVOF sprayed coatings samples, while bond strength, coating microhardness, and abrasion resistance of the hybrid-sprayed coatings were essentially unchanged.…”

“…Based on published results, it can be concluded, that the obtained coatings have got different properties, despite the similar chemical composition . The decisive role played [1][2][3][4][5][6][7][8] At first, the energy (supplied during the spraying process) forms a kind of phases in the coating material. The technology of spraying has got significant role in the forming process.…”

“…Until now, the system was used only for welding technologies [15][16][17][18][19][20][21]. The latest national and international research publications contained findings and information, that indicate, that the cooling system of micro-jet gives the ability to control the structure and can be successfully used in automated thermal spray technologies of coatings [1][2][3][4][5][6].…”

“…The jets injector allows to obtain coatings in a shorter time than in conventional spray methods. These coatings have a dense structure, low porosity and good adhesion to the substrate, and comparable or better properties, such as corrosion, corrosion -erosion and abrasive resistance at the high or elevated temperature [1][2][3][4][5][6][7][8][9][10][11][12]. The structure is a result of high speed of particle spraying and the micro-jet cooling system.…”

A Comparison of the Potential Capability of SFS, SPS and HVSFS for the Production of Photocatalytic Titania Coatings

“…[1][2][3] Each of these techniques utilises different thermal spray torches, giving rise to different particle temperatures and velocities. [4] This has significant effects on coating microstructure and phase composition, which in turn affects coating photoactivity. There have been a number of papers which compare the photocatalytic properties of HVSFS and SPS TiO2 coatings.…”