Effect of Kaolin Addition on Electrochemical Corrosion Resistance of Duplex 2205 Stainless Steel Embedded in Concrete Exposed in Marine Environment

2020 ◽  
pp. 11732-11741
Author(s):  
Ping Sheng ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Marine Environment ◽  
Electrochemical Corrosion ◽  
Electrochemical Corrosion Resistance

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.

Electrochemical corrosion performances of laser thermal sprayed amorphous Al–Ti–Ni coatings in marine environment

2020 ◽  
Vol 67 (2) ◽  
pp. 140-149
Author(s):  
Kong Dejun ◽  
Chen Haixiang
Keyword(s):  
Corrosion Resistance ◽  
Marine Environment ◽  
Laser Power ◽  
Electrochemical Corrosion ◽  
Amorphous Coating ◽  
Corrosion Performance ◽  
Scanning Calorimetry ◽  
Content Type ◽  
X Ray ◽  
Electrochemical Corrosion Resistance

Purpose The purpose of this paper is to investigate the effects of laser power on the electrochemical corrosion performance in 3.5% NaCl, 0.1 M H2SO4 and 0.1 M NaOH solutions, which provided an experimental basis for the application of Al–Ti–Ni amorphous coating in marine environment. Design/methodology/approach Amorphous Al–Ti–Ni coatings were fabricated on S355 structural steel by laser thermal spraying (LTS) at different laser powers. The surface and cross-section morphologies, chemical element distribution, phases and crystallization behaviors of obtained coatings were analyzed using a scanning electron microscope, energy-dispersive X-ray spectroscope, X-ray diffraction and differential scanning calorimetry, respectively. The effects of laser power on the electrochemical corrosion performances of Al–Ti–Ni coatings in 3.5% NaCl, 0.1 M H2SO4 and 0.1 M NaOH solutions were investigated using an electrochemical workstation. Findings The crystallization temperature of Al–Ti–Ni coatings fabricated at the laser power of 1,300 and 1,700 W is ∼520°C, whereas that fabricated at the laser power of 1,500 W is ∼310°C. The coatings display excellent corrosion resistance in 3.5% NaCl and 0.1 M NaOH solutions, while a faster dissolution rate in 0.1 M H2SO4 solution. The coatings fabricated at the laser power of 1,300 and 1,700 W present the better electrochemical corrosion resistance in 3.5% NaCl and 0.1 M NaOH solutions, whereas that fabricated at the laser power of 1,500 W exhibits the better electrochemical corrosion resistance in 0.1 M H2SO4 solution. Originality/value In this work, Al-wire-cored Ti–Ni powder was first on S355 steel with the laser power of 1,300, 1,500 and 1,700 W, and the effects of laser power on the electrochemical corrosion performance in 3.5% NaCl, 0.1 M H2SO4 and 0.1 M NaOH solutions were investigated using an electrochemical workstation.

Electrochemical corrosion resistance of thermal oxide formed on anodized stainless steel

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hongda Deng ◽  
Yongliang Liu ◽  
Zhen He ◽  
Xiantao Gou ◽  
Yefan Sheng ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Design Methodology ◽  
Electrochemical Corrosion ◽  
Constant Density ◽  
Content Type ◽  
Thermal Oxide ◽  
Pitting Corrosion Resistance ◽  
Dynamic Potential ◽  
Electrochemical Corrosion Resistance

Purpose The purpose of this paper is to investigate and explain thermal oxide effect on electrochemical corrosion resistance anodized stainless steel (SS). Design/methodology/approach Electrochemical corrosion resistance of thermal oxides produced on anodized 304 SS in air at 350°C, 550°C, 750°C and 950°C in 3.5 wt.% NaCl solution have been investigated by dynamic potential polarization, EIS and double-loop dynamic polarization. Anodized 304 SS were obtained by anodization at the constant density of 1.4 mA.cm-2 in the solution containing 28.0 g.L-1H3PO4, 20.0 g.L-1C6H8O7, 200.0 g.L-1H2O2 at 70°C for 50 min. SEM and EDS had been also used to characterize the thermal oxides and passive oxide. Findings Interestingly, anodized 304SS with thermal oxide produced at 350°C displayed more electrochemical corrosion and pitting resistance than anodized 304 SS only with passive oxide, as related to the formation of oxide film with higher chromium to iron ratio. Whereas, anodized 304SS with thermal oxide formed at 950°C shows the worse electrochemical corrosion and pitting resistance among those formed at the high temperatures due to thermal oxide with least compact. Originality/value When thermally oxidized in the range of 350°C–950°C, electrochemical corrosion and pitting corrosion resistance of anodized 304 SS decrease with the increase of temperature due to less compactness, more defects of thermal oxide.

scholarly journals Effect of Plasma Nitriding Process Conditions on Corrosion Resistance of 440B Martensitic Stainless Steel

2014 ◽  
Vol 8 (3) ◽  
pp. 156-159 ◽  
Author(s):  
Magdalena Łępicka ◽  
Małgorzata Grądzka-Dahlke
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Degradation Products ◽  
Plasma Nitriding ◽  
Electrochemical Corrosion ◽  
Industrial Applications ◽  
Process Conditions ◽  
Corrosion Properties ◽  
Dental Instruments ◽  
Increased Risk

Abstract Martensitic stainless steels are used in a large number of various industrial applications, e.g. molds for plastic injections and glass moldings, automotive components, cutting tools, surgical and dental instruments. The improvement of their tribological and corrosion properties is a problem of high interest especially in medical applications, where patient safety becomes a priority. The paper covers findings from plasma nitrided AISI 440B (PN-EN or DIN X90CrMoV18) stainless steel corrosion resistance studies. Conventionally heat treated and plasma nitrided in N2:H2 reaction gas mixture (50:50, 65:35 and 80:20, respectively) in two different temperature ranges (380 or 450°C) specimens groups were examined. Microscopic observations and electrochemical corrosion tests were performed using a variety of analytical techniques. As obtained findings show, plasma nitriding of AISI 440B stainless steel, regardless of the process temperature, results in reduction of corrosion current density. Nevertheless, applying thermo-chemical process which requires exceeding temperature of about 400°C is not recommended due to increased risk of steel sensitization to intergranular and stress corrosion. According to the results, material ion nitrided in 450°C underwent leaching corrosion processes, which led to significant disproportion in chemical composition of the corroded and corrosion-free areas. The authors suggest further research into corrosion process of plasma nitrided materials and its degradation products.

Appraisal on corrosion performances of CrNi, TiAlN/CrNi and CrNi–Al2O3–TiO2 coatings on H13 hot work mold

2020 ◽  
Vol 67 (2) ◽  
pp. 150-157
Author(s):  
Kong Dejun ◽  
Li Jiahong
Keyword(s):  
Corrosion Resistance ◽  
Salt Spray ◽  
Test Chamber ◽  
Electrochemical Corrosion ◽  
Optical Microscope ◽  
Electrochemical Performances ◽  
X Ray Diffraction ◽  
H13 Steel ◽  
Content Type ◽  
Electrochemical Corrosion Resistance

Purpose The purpose of this paper is to evaluate the salt spray corrosion (SSC) and electrochemical corrosion performances of CrNi, TiAlN/NiCr and CrNi–Al2O3–TiO2 coatings on H13 steel, which improved the corrosion resistance of H13 hot work mold. Design/methodology/approach CrNi, TiAlN/NiCr and CrNi–Al2O3–TiO2 coatings were fabricated on H13 hot work mold steel using a laser cladding and cathodic arc ion plating. The SSC and electrochemical performances of obtained coatings were investigated using a corrosion test chamber and electrochemical workstation, respectively. The corrosion morphologies, microstructure and phases were analyzed using an electron scanning microscope, optical microscope and X-ray diffraction, respectively, and the mechanisms of corrosion resistance were also discussed. Findings The CrNi coating is penetrated by corrosion media, producing the oxide of Fe3O4 on the coating surface; and the TiAlN coating is corroded to enter into the CrNi coating, forming the oxides of TiO and NiO, the mechanism is pitting corrosion, whereas the CrNi–Al2O3–TiO2 coating is not penetrated, with no oxides, showing the highest SSC resistance among the three kinds of coatings. The corrosion potential of CrNi coating, TiAlN/CrNi and CrNi–Al2O3–TiO2 coatings was –0.444, –0.481 and –0.334 V, respectively, and the corresponding polarization resistances were 3,074, 2,425 and 86,648 cm2, respectively. The electrochemical corrosion resistance of CrNi–Al2O3–TiO2 coating is the highest, which is enhanced by the additions of Al2O3 and TiO2. Originality/value The CrNi, TiAlN/CrNi and CrNi–Al2O3–TiO2 coatings on H13 hot work mold were firstly evaluated by the SSC and electrochemical performances.

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