The study of mechanical properties and corrosion behavior of the Fe-based amorphous alloy coatings using high velocity oxygen fuel spraying

2021 ◽  
Vol 867 ◽  
pp. 159132
Author(s):  
Tzu-Jing Lin ◽  
Hung-Hua Sheu ◽  
Chun-Ying Lee ◽  
Hung-Bin Lee
Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1533
Author(s):  
Jianxing Yu ◽  
Xin Liu ◽  
Yang Yu ◽  
Haoda Li ◽  
Pengfei Liu ◽  
...  

High-velocity oxygen fuel (HVOF)-sprayed amorphous alloy coatings usually have advantages of a dense structure that improve their resistance to corrosion, wear, and fatigue in the substrate. The flame flow characteristics and particle behaviors during the spray process have a significant influence on the amorphous coating structure and properties. In this study, a computational fluid dynamics model is enforced to analyze the flame flow and Fe-based amorphous alloy particle behavior in an HVOF spray process. The flame flow temperature, velocity characteristics, and the Fe48Cr15Mo14C15B6Y2 Fe-based amorphous alloy particles’ velocities, temperatures, flight trajectories, and mass concentration distribution characteristics are simulated. Moreover, the effects of the oxygen/fuel ratio, particle morphology parameter, particle-injection rate, and angle on the particle behavior are also investigated. Judging from the simulation results, the optimum amorphous alloy particle size varies between 20 and 30 μm, the shape factor is within the range of 0.9–1, the optimum O/F ratio is 3.4, the optimum injection angle is 45°, and the optimum injection rate is 10 m/s. With these conditions, most of the particles settled toward the centerline of the spray gun and are in a semisolid or solid state before affecting the substrate, giving the materials optimal coating structure and performance.


1999 ◽  
Vol 122 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Y. Itoh ◽  
M. Saitoh ◽  
M. Tamura

High velocity oxygen-fuel (HVOF) spraying system in open air has been established for producing the coatings that are extremely clean and dense. It is thought that the HVOF sprayed MCrAlY (M is Fe, Ni and/or Co) coatings can be applied to provide resistance against oxidation and corrosion to the hot parts of gas turbines. Also, it is well known that the thicker coatings can be sprayed in comparison with any other thermal spraying systems due to improved residual stresses. However, thermal and mechanical properties of HVOF coatings have not been clarified. Especially, the characteristics of residual stress, that are the most important property from the view point of production technique, have not been made clear. In this paper, the mechanical properties of HVOF sprayed MCrAlY coatings were measured in both the case of as-sprayed and heat-treated coatings in comparison with a vacuum plasma sprayed MCrAlY coatings. It was confirmed that the mechanical properties of HVOF sprayed MCrAlY coatings could be improved by a diffusion heat treatment to equate the vacuum plasma sprayed MCrAlY coatings. Also, the residual stress characteristics were analyzed using a deflection measurement technique and a X-ray technique. The residual stress of HVOF coating was reduced by the shot-peening effect comparable to that of a plasma spray system in open air. This phenomena could be explained by the reason that the HVOF sprayed MCrAlY coating was built up by poorly melted particles. [S0742-4795(00)00701-8]


2018 ◽  
Vol 1 (1) ◽  
pp. 558-564
Author(s):  
Hüseyin Köken ◽  
Hasan Kaya ◽  
Ramazan Samur ◽  
Mehmet Uçar

In this study, spectral analyzes were performed to determine the chemical composition of the samples at 2x40x40 mm taken from aluminum alloy sheet materials. Plates to be combined with friction stir welding were mechanically cut with guillotine scissors at 2x100x300mm. The welded joints of the aluminum plates to be friction-mixed are coated with titanium-based powder material with a thickness of 40µm by high velocity oxygen fuel spraying (HVOF) method. A friction stir tool with a cone tip geometry with machining, 20mm shoulder diameter and 1.8mm pin height was produced for use in the friction stir welding process. In addition, the aluminum alloy sheets prepared were machined according to ASTM E8M-04 standard with dimensions of 2x100x300mm so that they could be joined with friction stir welding on the milling bench. Waterjet drawing and metallographic samples were cut from welded aluminum plates formed with parameters of 2000 rpm rotation speed and 140 mm / min welding speed and 2 degree head angle in accordance with ASTM E8M-04 standard. Tensile specimens were measured on the universal drafting table at a pulling speed of 2 mm / min along with the maximum tensile breaking values ??as well as percent elongation. In order to determine the microstructure and mechanical properties of the weld inserts, hot stamping of the samples, which were not affected by heat, was followed by coarse and fine sanding followed by final polishing with 1µm diamond paste. The hardness values of the samples were determined by Vickers hardness measurement along an axis to characterize the welded zone upper, middle and lower zones to cover all weld zones and the main material.


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