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.

Corrosive wear and electrochemical corrosion performances of arc sprayed Al coating in 3.5% NaCl solution

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Peng Li ◽  
Xiya Huang ◽  
Dejun Kong
Keyword(s):  
Abrasive Wear ◽  
Wear Mechanism ◽  
Electrochemical Corrosion ◽  
Corrosive Wear ◽  
Corrosion Mechanism ◽  
Nacl Solution ◽  
Fatigue Wear ◽  
Wear Performance ◽  
Content Type ◽  
Al Coating

Purpose The purpose of this paper is to investigate the effects of load and speed on the corrosive wear performance of Al coating in 3.5% NaCl solution, which provided an experimental reference for the anti-corrosion engineering on offshore platforms. Design/methodology/approach A layer of Al coating was prepared on S355 steel using an arc spraying. The corrosive wear test was carried out with CFT–1 type surface property tester. The effects of load and speed on the corrosive wear performance of Al coating were investigated and the wear mechanism was also discussed. The electrochemical tests were conducted using a CHI660E type electrochemical workstation, the anti-corrosion mechanism was analyzed. Findings The average coefficient of frictions (COFs) of Al coating under loads of 1.5, 2.5 and 3.5 N are 0.745, 0.847 and 0.423, the wear mechanism is abrasive wear. The average COFs of Al coating at the speeds of 200, 400 and 600 rpm are 0.745, 0.878 and 0.617, respectively, the wear mechanism at the speeds of 200 and 400 rpm are abrasive wear, while that at the speed of 600 rpm is abrasive wear and fatigue wear. The anti-corrosion mechanism is the isolation of Cl– corrosion and cathodic protection of sacrificial anode. Originality/value This paper mainly studied corrosive wear and electrochemical corrosion performances of Al coating. This study hereby confirms that this manuscript is the original work and has not been published nor has it been submitted simultaneously elsewhere. This paper further confirms that all authors have checked the manuscript and have agreed to the submission.

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.

IMMERSION AND ELECTROCHEMICAL TESTS STUDY ON CORROSION RESISTANCE OF CHROME-FREE CHEMICAL CONVERSION FILM ON AZ91D Mg ALLOY IN 5 wt% NaCl SOLUTION

2005 ◽  
Vol 12 (03) ◽  
pp. 417-424
Author(s):  
X. P. ZHANG ◽  
G. CHEN
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Chemical Conversion ◽  
Alloy Coating ◽  
Charge Transfer Resistance ◽  
Mg Alloy ◽  
Nacl Solution ◽  
Transfer Resistance ◽  
Electrochemical Tests

Immersion and electrochemical tests have been applied to study corrosion protection of AZ91D Mg alloy coating with chrome-free chemical conversion (CCC) coat in 5wt% NaCl solution. The immersions tests include weight-loss measurements after full or partial immersion with whole coating and full immersion with damaged coating. The electrochemical tests include electrochemical impedance spectroscopy (EIS) and polarization curves measurement. The results of immersion and electrochemical tests show that chrome-free chemical conversion (CCC) surface treatment can significantly improve the corrosion resistance of AZ91D Mg alloy in 5% NaCl solution, and that the corrosion protection effect of CCC coating is not sensitive to pores or cracks. The equivalent circuit models are fitted from Nyquist plots for the uncoated specimens and the CCC-coated specimens. The charge transfer resistance, R ct , increases from about 1.669 Ω cm2 for the uncoated alloy to about 210 Ω cm2 after the alloy is coated with CCC coating.

CORROSION PROTECTION OF AZ91D Mg ALLOY COATING WITH MICRO-ARC OXIDATION FILM EVALUATED BY IMMERSION AND ELECTROCHEMICAL TESTS

2005 ◽  
Vol 12 (02) ◽  
pp. 279-287 ◽  
Author(s):  
X. P. ZHANG ◽  
G. CHEN
Keyword(s):  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Alloy Coating ◽  
Charge Transfer Resistance ◽  
Mg Alloy ◽  
Nacl Solution ◽  
Transfer Resistance ◽  
Electrochemical Tests ◽  
Micro Arc Oxidation ◽  
Eis Measurements

This paper describes the preliminary results of corrosion protection of AZ91D Mg alloy coated with a micro-arc oxidation (MAO) coating. The corrosion behavior of coated substrates was evaluated by means of immersion and electrochemical tests in 5 wt.% NaCl solution. The immersions tests include weight loss measurement after full or partial immersion with the whole coat and full immersion with the damaged coat. The electrochemical tests include polarization curves and electrochemical impedance spectroscopy (EIS) measurements. The results of immersion and electrochemical tests show that micro-arc oxidation (MAO) surface treatment can significantly improve the corrosion resistance of the AZ91D Mg alloy in 5% NaCl solution, and the corrosion protection effect of the MAO coating is not sensitive to pores or cracks in the coating. The charge transfer resistance R ct , increases from about 1.669Ωcm2 for the uncoated alloy to about 1113Ωcm2 after being coated with MAO coat.

Corrosion performance of mild steel and epoxy coated rebar in concrete under simulated harsh environment

2019 ◽  
Vol 37 (5) ◽  
pp. 657-678
Author(s):  
Muazzam Ghous Sohail ◽  
Mohammad Salih ◽  
Nasser Al Nuaimi ◽  
Ramazan Kahraman
Keyword(s):  
Mild Steel ◽  
Polarization Resistance ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Charge Transfer Resistance ◽  
Harsh Environment ◽  
Corrosion Performance ◽  
Transfer Resistance ◽  
Content Type ◽  
Rc Structures

Purpose The purpose of this paper is to present the results of a two-year long study carried out in order to evaluate the corrosion performance of mild steel bare bars (BB) and epoxy-coated rebar (ECR) in concrete under a simulated harsh environment of chlorides. Design/methodology/approach The blocks are subjected to Southern Exposure testing. The electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and Tafel plot are performed to measure the polarization resistance and corrosion current densities of these rebars. Knife-peel test was performed to assess the adhesion between epoxy and underlying steel after two years of exposure. Findings Mild steel BB showed a high corrosion current density of 1.24 µA/ cm2 in Tafel plots and a very low polarization resistance of 4.5 kΩ cm2 in LPR technique, whereas very high charge transfer resistance of 1672 and 1675 kΩ cm2 is observed on ECR and ECR with controlled damage (ECRCD), through EIS technique, respectively. EIS is observed to be a suitable tool to detect the defects in epoxy coatings. After two years of immersion in 3.89 percent NaCl− solution, the mild steel BB were severely corroded and a considerable weight loss was observed, whereas under heavy chloride attack, ECR showed no deterioration of epoxy coating and neither any corrosion of underlying steel. Results of this study show that the durability of reinforced concrete (RC) structures with respect to corrosion could be enhanced by using ECR, especially in harsh climatic conditions. Originality/value The corrosion performance of mild steel and ECR in concrete under a simulating splash zone environment is evaluated. EIS was used to evaluate the health of epoxy and corrosion state of underneath steel rebars. EIS was able to detect the defects in epoxy. The durability of RC structures could be enhanced in harsh climate regions by using ECR.

Effects of Tribo-Couple and Environmental Medium on the Tribological Properties of the Graphite/CaF2/TiC/Ni-Base Alloy Composite Coating

2013 ◽  
Vol 834-836 ◽  
pp. 644-648
Author(s):  
Bin Cai ◽  
Hua Bing Li ◽  
Ye Fa Tan ◽  
Hong Wei Li ◽  
Qi Feng Jing ◽  
...  
Keyword(s):  
Wear Rate ◽  
Composite Coating ◽  
Tribological Properties ◽  
Base Alloy ◽  
Alloy Coating ◽  
Dry Sliding ◽  
Wear Property ◽  
Alloy Composite ◽  
Nacl Solution ◽  
Wear Rates

The graphite/CaF2/TiC/Ni-base alloy composite coating was prepared on the surface of 45 carbon steel by plasma spray. Effects of loads, friction counterparts and lubricants on the tribological properties of the composite coating were investigated. The results show that the wear rate of the GCTN composite coating against Si3N4is 0.67×10-3mm3/m, which is about 2 times that against GCr15 steel, because Si3N4induces micro-cutting wear of the composite coating. Water and NaCl solution may induce increasing of friction coefficients and wear rates. Especially, wear rate of the GCTN composite coating in NaCl solution is increased by 3.1 times compared with those under dry sliding and water. The GCTN composite coating presents better anti-wear property than Ni-base alloy coating in different environmental mediums.

Investigation on the effect of nano-ceria on the epoxy coatings for corrosion protection of mild steel in natural seawater

2018 ◽  
Vol 65 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Joseph Raj Xavier
Keyword(s):  
Charge Transfer ◽  
Mild Steel ◽  
Charge Transfer Resistance ◽  
Epoxy Coating ◽  
Coated Sample ◽  
Natural Seawater ◽  
Film Resistance ◽  
Transfer Resistance ◽  
Content Type ◽  
Nano Ceria

Purpose This paper aims to investigate the effect of introducing nano-ceria (CeO2) particles to the epoxy coatings on mild steel in natural seawater. Design/methodology/approach The epoxy–ceria nanoparticles were coated with mild steel using a wire-wound draw-down bar method. The effects of ceria nanoparticles on the corrosion resistance of epoxy-coated samples were analyzed using scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS). Findings Localized measurements such as oxygen consumption and iron dissolution were observed using SECM in natural seawater in the epoxy-coated sample. The increase in film resistance (Rf) and charge transfer resistance (Rct) values by the addition of nano-ceria particles in the epoxy coating was measured from EIS measurements after wet and dry cyclic corrosion test. Scanning electron microscope (SEM)/energy dispersive X-ray spectroscope (EDX) analysis showed that complex oxides of nano-ceria were enriched in corrosion products at a scratched area of the coated mild steel after corrosion testing. Focused ion beam-transmission electron microscope (FIB-TEM) analysis confirmed the presence of the nanoscale oxide layers of ceria in the rust of the steel. Research limitations/implications The tip current at −0.70 V for the epoxy–CeO2-coated sample decreased rapidly because of cathodic reduction of the dissolved oxygen. The increase in film resistance (Rf) and charge transfer resistance (Rct) values by the addition of nano-ceria particles in the epoxy coating were measured from EIS measurements after wet and dry cyclic corrosion test. Practical implications The presence of complex oxide layers of nano-ceria layers protects the coated steel from rusting. Social implications The use of this nano-ceria for corrosion protection is environment-friendly. Originality/value The results of this study indicated the significant effect of nano-ceria particles on the protective performance and corrosion resistance of the epoxy coating on mild steel. The dissolution of Fe2+ was lower in the epoxy–ceria nanoparticle-coated mild steel than that of the epoxy-coated mild steel resulting in a lower anodic current of steel. The increase in film resistance and the charge transfer resistance showed that the nano-ceria particles and the formation of complex oxides provide better barrier protection to the coating metal surfaces.

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.

Study on Abrasive Wear Behavior and Mechanisms of 7Cr7Mo2V2Si Steel as Drilling Tool Materials

2011 ◽  
Vol 239-242 ◽  
pp. 2986-2992
Author(s):  
Ye Fa Tan ◽  
Bin Cai ◽  
Xiao Long Wang ◽  
Guo Liang Jiang ◽  
Chun Hua Zhou
Keyword(s):  
Abrasive Wear ◽  
Wear Behavior ◽  
Normal Load ◽  
Fine Powder ◽  
Corrosive Wear ◽  
Wear Loss ◽  
Drilling Tool ◽  
Sliding Speed ◽  
Wear Rates ◽  
Abrasive Wear Behavior

In order to search for new wear resistant materials used as drilling tools and improve the service life and drilling efficiency, the 7Cr7Mo2V2Si steel was prepared and its abrasive wear behavior and mechanisms were studied under both dry and water wear conditions. The research results show that the wear losses of the 7Cr7Mo2V2Si steel increase with the increase of normal load and sliding speed at both of dry and water wear conditions. The wear losses become greatly increase at high sliding speed and heavy normal load wear conditions. The wear rates of the 7Cr7Mo2V2Si steel at water wear conditions are bigger than those at dry wear conditions. The existence of water will aggravate the wear loss of the steel because water can clean the tribo-interface by taking away the fine powder or debris, which may keep the corundum abrasives protruding and remaining sharp edge state to produce more serious two-body abrasive wear to the steel, and meanwhile the collaborative action of the friction stress and the corrosion may result in stress corrosive wear of the steel. The main wear mechanisms of the 7Cr7Mo2V2Si steel are micro-cutting wear, multi-plastic deformation wear at dry wear conditions and accompanied with stress corrosive wear at water wear conditions.

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