Electrochemical Corrosion Behavior of Heat Treated HVOF Coatings on ASTM SA213-T22 steel

CORROSION ◽  
10.5006/3957 ◽  
2021 ◽  
Author(s):  
sakthivel kandaiah
Keyword(s):  
Electrochemical Corrosion ◽  
Charge Transfer Resistance ◽  
Tube Steel ◽  
Boiler Tube ◽  
Transfer Resistance ◽  
Hvof Coatings ◽  
Heat Treated ◽  
Boiler Tube Steel ◽  
Electrochemical Corrosion Behavior ◽  
Very High

Herein we report the electrochemical corrosion behavior of pre and post heat-treated composite coatings of NiCrMoFeCoAl-30%SiO2 and NiCrMoFeCoAl-30%Cr2O3 on ASTM SA213-T22 boiler tube steel by high velocity oxygen fuel (HVOF) spraying technique. The samples were subjected to hot molten salt (Na2SO4–60%V2O5) corrosion environment in a tubular furnace at 7000C under thermocyclic conditions. The microscopic, structural and electrochemical investigations of post-heat treated specimens reveal NiCrMoFeCoAl-30%Cr2O3 composite HVOF coating exhibits a superior corrosion resistance compared to NiCrMoFeCoAl-30%SiO2 composite coating and bare ASTM SA213-T22 steel boiler tube steel in neutral electrolyte. The room temperature potentiodynamic and impedance investigations of heat-treated samples suggest high interfacial charge transfer resistance for HVOF coatings over a wide anodic potential window. This could be ascribed to the protective nature of the chromium oxide containing coatings on high temperature treatment. AC impedance analysis reveals NiCrMoFeCoAl-30%Cr2O3 coating exhibits very high resistive behaviour with very high charge transfer resistance, in the order of 106 Ohm higher than the NiCrMoFeCoAl-30%SiO2 coating and uncoated ASTM SA213-T22 steel boiler tube steel. Furthermore, the high temperature induced formation of metal chromates/chromites along with the presence of Cr2O3 provides good resistance towards corrosion.

scholarly journals Particle Size-Dependent Microstructure, Hardness and Electrochemical Corrosion Behavior of Atmospheric Plasma Sprayed NiCrBSi Coatings

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1342 ◽  
Author(s):  
Peng Sang ◽  
Liang-Yu Chen ◽  
Cuihua Zhao ◽  
Ze-Xin Wang ◽  
Haiyang Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Corrosion Behavior ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Charge Transfer Resistance ◽  
Atmospheric Plasma ◽  
Transfer Resistance ◽  
Electrochemical Corrosion Behavior ◽  
Plasma Sprayed ◽  
Nicrbsi Coatings

Particle size is a critical consideration for many powder coating-related industries since it significantly influences the properties of the produced materials. However, the effect of particle size on the characteristics of plasma sprayed NiCrBSi coatings is not well understood. This work investigates the microstructures, hardness and electrochemical corrosion behavior of plasma sprayed NiCrBSi coatings synthesized using different-sized powders. All coatings mainly consist of Ni, N3B, CrB, Cr7C3 and Cr3C2 phases. The coatings produced by small particles (50–75 μm) exhibit lower porosity (2.0 ± 0.8%). Such coatings show a higher fraction (15.5 vol.%) of the amorphous phase and lower hardness (700 HV0.5) than the counterparts (8.7 vol.% and 760 HV0.5, respectively) produced by large particles (75–100 μm) with higher porosity (3.0 ± 1.6%). Meanwhile, the coatings produced from smaller particles possess a larger number of non-bonded boundaries, leading to the easier penetration of corrosive medium, as well as a higher corrosion current density (0.254 ± 0.062 μA/cm2) and a lower charge transfer resistance (0.37 ± 0.07 MΩ cm2). These distinctions are attributed to particle size-induced different melting degrees and stackings of in-flight particles during deposition.

scholarly journals Electrochemical Corrosion Behavior of Ni-Fe-Co-P Alloy Coating Containing Nano-CeO2 Particles in NaCl Solution

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2614 ◽  
Author(s):  
Xiuqing Fu ◽  
Wenke Ma ◽  
Shuanglu Duan ◽  
Qingqing Wang ◽  
Jinran Lin
Keyword(s):  
Composite Coating ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Alloy Coating ◽  
Charge Transfer Resistance ◽  
Corrosion Mechanism ◽  
Nacl Solution ◽  
Transfer Resistance ◽  
Electrochemical Corrosion Behavior

In order to study the effect of nano-CeO2 particles doping on the electrochemical corrosion behavior of pure Ni-Fe-Co-P alloy coating, Ni-Fe-Co-P-CeO2 composite coating is prepared on the surface of 45 steel by scanning electrodeposition. The morphology, composition, and phase structure of the composite coating are analyzed by means of scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The corrosion behavior of the coatings with different concentrations of nano-CeO2 particles in 50 g/L NaCl solution is studied by Tafel polarization curve and electrochemical impedance spectroscopy. The corrosion mechanism is discussed. The experimental results show that the obtained Ni-Fe-Co-P-CeO2 composite coating is amorphous, and the addition of nano-CeO2 particles increases the mass fraction of P. With the increase of the concentration of nano-CeO2 particles in the plating solution, the surface flatness of the coating increases. The surface of Ni-Fe-Co-P-1 g/L CeO2 composite coating is uniform and dense, and its self-corrosion potential is the most positive; the corrosion current and corrosion rate are the smallest, and the charge transfer resistance is the largest, showing the best corrosion resistance.

Corrosive wear and electrochemical corrosion behaviors of laser thermal sprayed CoCrAlYTaSi coatings in 3.5 Wt.% NaCl solution

2019 ◽  
Vol 66 (5) ◽  
pp. 537-543 ◽  
Author(s):  
Zhou Weitong ◽  
Kong Dejun
Keyword(s):  
Abrasive Wear ◽  
Chemical Elements ◽  
Electrochemical Corrosion ◽  
Alloy Coating ◽  
Corrosive Wear ◽  
Charge Transfer Resistance ◽  
Nacl Solution ◽  
Transfer Resistance ◽  
Content Type ◽  
Wear Rates

Purpose This paper aims to enhance the corrosive wear and electrochemical corrosion of Ti–6Al–4V alloy. Design/methodology/approach A CoCrAlYTaSi alloy coating was fabricated on Ti–6Al–4V alloy using a laser thermal spraying (LTS). The surface and cross-section morphologies, chemical elements, phases and bonding strength of the obtained coating were analyzed using a scanning electron microscope, energy dispersive spectroscope, X-ray diffraction and scratch test, respectively, The corrosive wear and electrochemical corrosion of CoCrAlYTaSi coating in 3.5 Wt.% NaCl solution were investigated using a wear tester and electrochemical workstation, respectively. Findings The average coefficient of frictions (COFs) of CoCrAlYTaSi coating under the wear loads of 2, 4 and 6 N are 1.31, 1.02 and 0.88, respectively; and the corresponding wear rates are 0.66 × 10−4, 1.10 × 10−4 and 1.30 × 10−4 mm3·N–1·m–1, respectively. The wear mechanism under the wear load of 2 N is abrasive wear, while those under the wear loads of 4 and 6 N are adhesive wear and abrasive wear. The charge transfer resistance of CoCrAlYTaSi coating is 5.368 × 105 Ω·cm2, higher than 2.193 × 105 of the substrate. Originality/value In this study, a CoCrAlYTaSi coating was firstly fabricated on Ti–6Al–4V alloy using a LTS. Its corrosive wear and electrochemical corrosion in 3.5 Wt.% NaCl solution were investigated, which played a protective role of corrosive wear on Ti–6Al–4V alloy.

Thermal Fatigue Behavior of Boiler Tube Steel

2003 ◽  
Vol 2003.1 (0) ◽  
pp. 155-156
Author(s):  
Shingo AOI ◽  
Ryuichiro EBARA ◽  
Takashi NISHIMURA ◽  
Hiroyuki TOKUNAGA
Keyword(s):  
Thermal Fatigue ◽  
Fatigue Behavior ◽  
Tube Steel ◽  
Boiler Tube ◽  
Boiler Tube Steel ◽  
Thermal Fatigue Behavior

Microstructural evolution and oxidation resistance of T92 boiler tube steel upon long-term supercritical steam test

2017 ◽  
Vol 125 ◽  
pp. 361-366 ◽  
Author(s):  
Kejian Li ◽  
Houyu Ma ◽  
Yinsheng He ◽  
Jungchel Chang ◽  
Si-yeon Bae ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
Microstructural Evolution ◽  
Tube Steel ◽  
Boiler Tube ◽  
Boiler Tube Steel
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