Characterization of corrosion resistance of Zn-Ni-W and Zn-Ni-P-W heat-treated coatings

2021 ◽  
Vol 25 (3-4) ◽  
pp. 13-17
Author(s):  
Magdalena Popczyk ◽  
Jolanta Niedbała
Keyword(s):  
Corrosion Resistance ◽  
Phase Composition ◽  
Surface Morphology ◽  
Electrochemical Corrosion ◽  
Nacl Solution ◽  
Heat Treated ◽  
Electrochemical Corrosion Resistance

The paper presents results of research concerning the evaluation of corrosion resistance of heat-treated alloy coatings (Zn-Ni-W/320°C and Zn-Ni-P-W/320°C). The surface morphology and phase composition of the obtained coatings were determined. Electrochemical corrosion resistance was studied in 5% NaCl solution. On the basis of these studies it was found that the corrosion resistance of Zn-Ni-P-W/320°C coating is higher than Zn-Ni-W/320°C coating.

Structure and Corrosion Resistance of Iron Coatings Containing Silicon Powders

2011 ◽  
Vol 399-401 ◽  
pp. 1926-1931 ◽  
Author(s):  
Yi Wang ◽  
Gang Chen ◽  
Wei Dong Liu ◽  
Qiong Yu Zhou ◽  
Qing Dong Zhong
Keyword(s):  
Corrosion Resistance ◽  
Phase Composition ◽  
Thermal Treatment ◽  
Surface Morphology ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Active Surface ◽  
Active Surface Area ◽  
Two Phase ◽  
Electrochemical Corrosion Resistance

Fe + Si coatings were prepared by iron deposition from a bath containing a suspension of silicon powders. These coatings were obtained at galvanostatic conditions, at the current density of jdep=−0.020 A cm−2 and at the temperature of 338 K. For determination of the influence of phase composition and surface morphology of these coatings on changes in the corrosion resistance, these coatings were modified in an argon atmosphere by thermal treatment at 873 K for 2h. A scanning electron microscope was used for surface morphology characterization of the coatings. The chemical composition of the coatings was determined by EDS and phase composition investigations were conducted by X-ray diffraction. It was found that the as-deposited coatings consist of a two-phase structure, i.e., iron and silicon. The phase composition for the Fe + Si coatings after thermal treatment is markedly different. The main peaks corresponding to Fe and Si coexist with the new phases: FeSi. Electrochemical corrosion resistance investigations were carried out in 3.5wt% NaCl, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found that the Fe + Si coatings after thermal treatment are more corrosion resistant in 3.5wt% NaCl solution than the as-deposited coatings. The reasons for this are a reduction in the amount of free iron and silicon, the presence of new phases (in particular silicides), and a decrease of the active surface area of the coatings after thermal treatment.

scholarly journals Microstructure and Corrosion Resistance of Underwater Laser Cladded Duplex Stainless Steel Coating after Underwater Laser Remelting Processing

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4965
Author(s):  
Congwei Li ◽  
Jialei Zhu ◽  
Zhihai Cai ◽  
Le Mei ◽  
Xiangdong Jiao ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Phase Composition ◽  
Duplex Stainless Steel ◽  
Electrochemical Corrosion ◽  
Chemical Components ◽  
Laser Remelting ◽  
Underwater Environment ◽  
Underwater Laser ◽  
Electrochemical Corrosion Resistance

Combined with the technologies of underwater local dry laser cladding (ULDLC) and underwater local dry laser remelting (ULDLR), a duplex stainless steel (DSS) coating has been made in an underwater environment. The phase composition, microstructure, chemical components and electrochemical corrosion resistance was studied. The results show that after underwater laser remelting, the phase composition of DSS coating remains unchanged and the phase transformation from Widmanstätten austenite + intragranular austenite + (211) ferrite to (110) ferrite occurred. The ULDLR process can improve the corrosion resistance of the underwater local dry laser cladded coating. The corrosion resistance of remelted coating at 3 kW is the best, the corrosion resistance of remelted coating at 1kW and 5kW is similar and the corrosion resistance of (110) ferrite phase is better than grain boundary austenite phase. The ULDLC + ULDLR process can meet the requirements of efficient underwater maintenance, forming quality control and corrosion resistance. It can also be used to repair the surface of S32101 duplex stainless steel in underwater environment.

Study on Anodic Oxidation of 2024 Aluminum Alloys in Sulfuric-Citric Acid

2014 ◽  
Vol 788 ◽  
pp. 236-242 ◽  
Author(s):  
Xiang Feng Meng ◽  
Guo Ying Wei ◽  
Xi Xi Zhao ◽  
Hong Liang Ge
Keyword(s):  
Corrosion Resistance ◽  
Citric Acid ◽  
Anodic Oxidation ◽  
Corrosion Potential ◽  
Electrochemical Corrosion ◽  
Mixed Solution ◽  
Nacl Solution ◽  
Maximum Hardness ◽  
Anodized Aluminum ◽  
Electrochemical Corrosion Resistance

Porous anodic alumina has been obtained through anodic oxidation in a mixed solution of sulfuric and citric acid. We investigated the microstructure and morphology of 2024 aluminum after being anodically oxidized under different voltage and temperature. Hardness and corrosion resistance of anodized aluminum has been also investigated. The results show that after anodization, many nanoholes appeared on the surface layer of the coating. Thickness of the anodized film increased from 2.7μm to 26.3μm with the voltage changing from 10 V to 18 V. Aodized films with the thickness of 18μm could be obtained under the temperature of 47°C. When the oxidation voltage is 12V, the hardness of the oxidation film reached 126HV. Maximum hardness (130 HV) could be achieved when the oxidation temperature was 57°C. After being dealt with in the NaCl solution, the electrochemical corrosion resistance of the anodic film got a sharp increase, and the anodic oxidation voltage had a great impact on the anodized film. When the oxidation voltage was 16V, the corrosion resistance of the film reached the highest value and the corrosion voltage was-0.7V. From the polarization curves, it has been found that the films obtained under the temperature of 37°C possessed more positive corrosion potential (-0.73V) and optimal anticorrosion performance.

scholarly journals Comparison on the immersion corrosion and electrochemical corrosion resistance of WC–Al2O3 composites and WC–Co cemented carbide in NaCl solution

RSC Advances ◽  
2021 ◽  
Vol 11 (36) ◽  
pp. 22495-22507
Author(s):  
Bin Han ◽  
Weiwei Dong ◽  
Bowen Fan ◽  
Shigen Zhu
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Corrosion ◽  
Cemented Carbide ◽  
Corrosion Mechanism ◽  
Nacl Solution ◽  
Immersion Corrosion ◽  
Electrochemical Corrosion Resistance

WC–Al2O3 composites possess higher corrosion resistance compared with WC–Co cemented carbide. The main corrosion mechanism for WC–Al2O3 composites is the oxidation of the WC phase.

scholarly journals Corrosion resistance of the microarc oxidation coatings prepared on magnesium alloy

2018 ◽  
Vol 38 ◽  
pp. 02009
Author(s):  
Ying Lv ◽  
Jun Gang Li ◽  
Ming Zhong Wu ◽  
Zhen Ma ◽  
Jing Qiang Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Microarc Oxidation ◽  
Electrochemical Corrosion ◽  
Ceramic Coatings ◽  
Nacl Solution ◽  
Oxide Coatings ◽  
Az91d Magnesium Alloy ◽  
Oxidation Technology ◽  
Electrochemical Corrosion Resistance

Ceramic coatings were prepared on the surface of AZ91D magnesium alloy by microarc oxidation technology. The effects of different voltages on morphology, phase composition and thickness of the coatings were characterized by SEM and XRD. The corrosion resistance of the coatings was measured by electrochemical workstation. Results indicated that the microarc oxidation coatings prepared in sodium silicate electrolyte exhibited porous surface and mainly comprised MgO, Mg2SiO4 and a small amount of MgAl2O4. The thickness of the oxide coatings increased rapidly with the increase of voltage. The coating prepared at 400V voltage had good electrochemical corrosion resistance in 3.5wt% NaCl solution.

scholarly journals Effects of Yttrium Addition on the Microstructure Evolution and Electrochemical Corrosion of SN-9zn Lead-Free Solders Al-Loy

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2549
Author(s):  
Wenchao Yang ◽  
Jun Mao ◽  
Yueyuan Ma ◽  
Shuyuan Yu ◽  
Hongping He ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Microstructure Evolution ◽  
Electrochemical Corrosion ◽  
Lead Free ◽  
Nacl Solution ◽  
Rich Phase ◽  
Yttrium Addition ◽  
Electrochemical Corrosion Behavior ◽  
Lead Free Solders ◽  
Addition Amount

Electrochemical corrosion behavior of ternary tin-zinc-yttrium (Sn-9Zn-xY) solder alloys were investigated in aerated 3.5 wt.% NaCl solution using potentiodynamic polarization techniques, and the microstructure evolution was obtained by scanning electron microscope (SEM). Eight different compositions of Sn-9Zn-xY (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10, 0.20, and 0.30 wt.%) were compared by melting. The experimental results show that when the content of Y reached 0.06 wt.%, the grain size of Zn-rich phase became the smallest and the effect of grain refinement was the best, but there was no significant effect on the melting point. With the increases of Y content, the spreading ratio first increased and then decreased. When the content of Y was 0.06 wt.%, the Sn-9Zn-0.06Y solder alloy had the best wettability on the Cu substrate, which was increased by approximately 20% compared with Sn-9Zn. Besides, the electrochemical corrosion experimental shows that the Y can improve the corrosion resistance of Sn-9Zn system in 3.5 wt.% NaCl solution, and the corrosion resistance of the alloy is better when the amount of Y added is larger within 0.02–0.30 wt.%. Overall considering all performances, the optimal performance can be obtained when the addition amount of Y is 0.06.

scholarly journals Effect of Fluid Flow on the Corrosion Performance of as-Cast and Heat-Treated Nickel Aluminum Bronze Alloy (UNS C95800) in Saline Solution

2021 ◽  
Vol 2 (1) ◽  
pp. 61-77
Author(s):  
Hamid Reza Jafari ◽  
Ali Davoodi ◽  
Saman Hosseinpour
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Flow Rate ◽  
Solution Temperature ◽  
Aluminum Bronze ◽  
Nickel Aluminum ◽  
Nacl Solution ◽  
Flow Conditions ◽  
Heat Treated ◽  
Nickel Aluminum Bronze

In this work, the corrosion behavior and surface reactivity of as-cast and heat-treated nickel aluminum bronze casting alloy (UNS C95800) in 3.5 wt% NaCl solution is investigated under stagnant and flow conditions. Increasing flow rate conditions are simulated using a rotating disk electrode from 0 to 9000 revolutions per minute (rpm). Optical micrographs confirm the decrease in the phase fraction of corrosion-sensitive β phase in the microstructure of C95800 after annealing, which, in turn, enhances the corrosion resistance of the alloy. Electrochemical studies including open circuit potentiometry, potentiodynamic polarization, and electrochemical impedance spectroscopy are performed to assess the effect of flow rate and heat treatment on the corrosion of samples at 25 and 40 °C in 3.5 wt% NaCl solution. For both as-cast and heat-treated samples, increasing the flow rate (i.e., electrode rotating rate) linearly reduces the corrosion resistance, indicating that the metal dissolution rate is significantly affected by hydrodynamic flow. Increasing the solution temperature negatively impacts the corrosion behavior of the as-cast and heat-treated samples at all flow conditions.

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