scholarly journals Numerical Analysis of High-Velocity Oxygen Fuel Thermal-Spray Process for Fe-Based Amorphous Coatings

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1533
Author(s):  
Jianxing Yu ◽  
Xin Liu ◽  
Yang Yu ◽  
Haoda Li ◽  
Pengfei Liu ◽  
...  
Keyword(s):  
Amorphous Alloy ◽  
High Velocity ◽  
Injection Rate ◽  
Amorphous Coating ◽  
High Velocity Oxygen Fuel ◽  
Alloy Particle ◽  
Coating Structure ◽  
Particle Behavior ◽  
Spray Process ◽  
Oxygen Fuel

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.

scholarly journals The Effect of Heat Treatment on the Corrosion Resistance of Fe-Based Amorphous Alloy Coating Prepared by High Velocity Oxygen Fuel Method

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7818
Author(s):  
Chun-Ying Lee ◽  
Hung-Hua Sheu ◽  
Leu-Wen Tsay ◽  
Po-Sen Hsiao ◽  
Tzu-Jing Lin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Amorphous Alloy ◽  
High Velocity ◽  
Annealing Temperature ◽  
Annealing Treatment ◽  
Alloy Coating ◽  
Corrosion Current ◽  
High Velocity Oxygen Fuel ◽  
Oxygen Fuel

In this study, Fe40Cr19Mo18C15B8 amorphous coatings were prepared using high velocity oxygen fuel (HVOF) technology. Different temperatures were used in the heat treatment (600 °C, 650 °C, and 700 °C) and the annealed coatings were analyzed by DSC, SEM, TEM, and XRD. XRD and DSC results showed that the coating started to form a crystalline structure after annealing at 650 °C. From the SEM observation, it can be found that when the annealing temperature of the Fe-based amorphous alloy coating reached 700 °C, the surface morphology of the coating became relatively flat. TEM observation showed that when the annealing temperature of the Fe-based amorphous alloy coating was 700 °C, crystal grains in the coating recrystallized with a grain size of 5–20 nm. SAED analysis showed that the precipitated carbide phase was M23C6 phase with different crystal orientations (M = Fe, Cr, Mo). Finally, the corrosion polarization curve showed that the corrosion current density of the coating after annealing only increased by 9.13 μA/cm2, which indicated that the coating after annealing treatment still had excellent corrosion resistance. It also proved that the Fe-based amorphous alloy coating can be used in high-temperature environments. XPS analysis showed that after annealing FeO and Fe2O3 oxide components increased, and the formation of a large number of crystals in the coating resulted in a decrease in corrosion resistance.

scholarly journals High-Velocity Oxygen Fuel Thermal Spray of Fe-Based Amorphous Alloy: a Numerical and Experimental Study

2009 ◽  
Vol 40 (9) ◽  
pp. 2231-2240 ◽  
Author(s):  
L. Ajdelsztajn ◽  
J. Dannenberg ◽  
J. Lopez ◽  
N. Yang ◽  
J. Farmer ◽  
...  
Keyword(s):  
Experimental Study ◽  
Amorphous Alloy ◽  
Thermal Spray ◽  
High Velocity ◽  
High Velocity Oxygen Fuel ◽  
Oxygen Fuel

COLMONOY NO. 43HV

Alloy Digest ◽  
2008 ◽  
Vol 57 (7) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Surface Treatment ◽  
High Velocity ◽  
Base Alloy ◽  
Heat Treating ◽  
High Velocity Oxygen Fuel ◽  
Nickel Base Alloy ◽  
Nickel Base ◽  
Oxygen Fuel

Abstract Colmonoy No. 43HV comprises a nickel-base alloy recommended for hard surfacing parts to resist wear, corrosion, heat, and galling. Deposits that have moderate hardness have increased ductility and slightly less resistance to abrasion than Colmonoy 53HV. Deposits can be finished by grinding or machined with carbide tooling. Colmonoy No. 43HV is supplied as an atomized powder specially sized for application with high-velocity oxygen fuel (HVOF) systems. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance and surface qualities as well as heat treating and surface treatment. Filing Code: Ni-664. Producer or source: Wall Colmonoy Corporation.

Difference oxidation behaviors of Ni8Al and Ni25Cr coatings in air with water vapor at 650∘

2021 ◽  
pp. 2150274
Author(s):  
Dingjun Li ◽  
Wenlang Huang ◽  
Xiaohu Yuan ◽  
Taihong Huang ◽  
Chao Li ◽  
...  
Keyword(s):  
Water Vapor ◽  
High Velocity ◽  
Cyclic Oxidation ◽  
Oxidation Behaviour ◽  
Fuel Spray ◽  
High Velocity Oxygen Fuel ◽  
Service Environment ◽  
Generator Unit ◽  
Oxygen Fuel ◽  
Oxidation Behaviors

The oxidation behaviour of Ni8Al and Ni25Cr coatings produced by high velocity oxygen fuel spray (HVOF) which were deposited on Fe-based alloys (CB2) was investigated. We simulated the service environment of the steam generator unit, and put the samples in a thermostatic tube furnace at 650[Formula: see text] in air with 20 wt.% water vapor for 1000 hours of cyclic oxidation. The formation mechanism are explained using SEM, XRD, and EDX. There were no spallations and obvious cracks in both coatings. Ni25Cr coating generated a better protection oxides scale than that scale on Ni8Al. The behavior and mechanism of the oxide scale formation had an important influence in coatings and we have discussed these phenomenons in the study.

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