scholarly journals Effects of the Combined Addition of Zn and Mg on Corrosion Behaviors of Electropainted AlSi-Based Metallic Coatings Used for Hot-Stamping Steel Sheets

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3379
Author(s):  
Si On Kim ◽  
Won Seog Yang ◽  
Sung Jin Kim
Keyword(s):  
Corrosion Resistance ◽  
Hot Stamping ◽  
Electrochemical Techniques ◽  
Corrosion Current ◽  
Selective Dissolution ◽  
Localized Corrosion ◽  
Steel Sheets ◽  
Corrosion Behaviors ◽  
Automotive Steel ◽  
Hot Stamping Steel

The effects of the combined addition of Zn and Mg on the corrosion resistance of AlSi-based coating for automotive steel sheets were investigated using a variety of analytical and electrochemical techniques. The preferential dissolution of Mg and Zn from MgZn2/Mg2Si phases occurred on the AlSi-based coating that had been alloyed with a smaller portion of Zn and Mg, which contributed to the rapid surface coverage by corrosion products with a protective nature, reducing the corrosion current density. On the other hand, localized corrosion attacks caused by the selective dissolution of Mg were also observed in the AlSi-based coating with a smaller portion of Zn and Mg. Such alloying can also worsen its corrosion resistance when coated additionally with electrodeposited paint. The mechanistic reasons for these conflicting results are also discussed.

scholarly journals Effect of Minor Alloying Elements (C, Ni, Cr, Mo) on the Long-Term Corrosion Behaviors of Ultrahigh-Strength Automotive Steel Sheet in Neutral Aqueous Environment

2022 ◽  
Vol 60 (1) ◽  
pp. 35-45
Author(s):  
Hye Rin Bang ◽  
Jin-seong Park ◽  
Hwan Goo Seong ◽  
Sung Jin Kim
Keyword(s):  
Corrosion Current ◽  
Alloying Elements ◽  
Aqueous Environment ◽  
Beneficial Effects ◽  
Steel Sheets ◽  
Ultrahigh Strength ◽  
Minor Addition ◽  
Corrosion Behaviors ◽  
Automotive Steel

This study examined the effects of minor alloying elements (C, Ni, Cr, and Mo) on the long-term corrosion behaviors of ultrahigh-strength automotive steel sheets with a tensile strength of more than 1800 MPa. A range of experimental and analytical results showed that the addition of Ni, Cr, and Mo decreased the corrosion current density and weight loss in electrochemical and immersion tests, respectively, in a neutral aqueous condition. This suggests that the minor addition of elements to steel can result in improved corrosion resistance even for long-term immersion periods. This is closely associated with the formation of thin and stable corrosion scale on the surface, which was enriched with the alloying elements (Ni, Cr, and Mo). On the other hand, their beneficial effects did not persist during the prolonged immersion periods in steel with a higher C content, suggesting that the beneficial effects of the minor addition of Ni, Cr, and Mo were overridden by the detrimental effects of a higher C content as the immersion time was increased. Based on these results, lower C and the optimal use of Ni, Cr, and Mo are suggested as a desirable alloy design strategy for developing ultrahigh-strength steel sheets that can be exposed frequently to a neutral aqueous environment.

scholarly journals Investigation of the Microstructural Evolution during Hot Stamping of a Carburized Complex Phase Steel by Laser-Ultrasonics

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1836
Author(s):  
Alexander Horn ◽  
Marion Merklein
Keyword(s):  
Microstructural Evolution ◽  
Hot Stamping ◽  
Laser Ultrasonics ◽  
Complex Phase ◽  
Finished Steel ◽  
Steel Sheets ◽  
Fine Grain ◽  
Martensitic Microstructure ◽  
Ultrasound Sensor ◽  
Hot Stamping Steel

Prior carburization of semi-finished steel sheets is a new process variant in hot stamping to manufacture parts with tailored properties. Compared to conventional hot stamping processes, a complex phase typed steel alloy is used instead of 22MnB5. Yet recent investigations focused on final mechanical properties rather than microstructural mechanisms cause an increase in strength. Thus, the influence of additional carburization on the microstructural evolution during hot stamping of a complex phase steel CP-W®800 is investigated within this work. The phase transformation behavior, as well as the grain growth during austenitization, is evaluated by in-situ measurements employing a laser-ultrasound sensor. The results are correlated with additional hardness measurements in as-quenched condition and supplementary micrographs. The experiments reveal that the carburization process significantly improves the hardenability of the CP-W®800. However, even at quenching rates of 70 K/s no fully martensitic microstructure was achievable. Still, the resulting hardness of the carburized samples might exceed the fully martensitic hardness of 22MnB5 derived from literature. Furthermore, the carburization process has no adverse effect on the fine grain stability of the complex phase steel. This makes it more robust in terms of grain size than the conventional hot stamping steel 22MnB5.

scholarly journals Chemical Composition and Corrosion Behavior of a-C:H/DLC Film-Coated Titanium Substrate in Simulated PEMFC Environment

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 820
Author(s):  
Beibei Han ◽  
Mengyuan Yan ◽  
Dongying Ju ◽  
Maorong Chai ◽  
Susumu Sato
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Metal Ion ◽  
Ion Beam ◽  
Titanium Substrate ◽  
Corrosion Current ◽  
Ion Concentration ◽  
Bipolar Plates ◽  
High Adhesion ◽  
Corrosion Behaviors

The amorphous hydrogenated (a-C:H) film-coated titanium, using different CH4/H2 and deposition times, was prepared by the ion beam deposition (IBD) method, which has the advantage of high adhesion because of the graded interface mixes at the atomic level. The chemical characterizations and corrosion behaviors of a-C:H film were investigated and evaluated by SEM, AFM, Raman spectroscopy, EPMA, TEM and XPS. An a-C:H film-coated titanium was corroded at 0.8 V, 90 °C in a 0.5 mol/L H2SO4 solution for 168 h. The metal ion concentration in the H2SO4 corrosion solution and the potentiodynamic polarization behavior were evaluated. Results indicate that a higher CH4/H2 of 1:0 and a deposition time of 12 h can result in a minimum ID/IG ratio of 0.827, Ra of 5.76 nm, metal ion concentration of 0.34 ppm in the corrosion solution and a corrosion current of 0.23 µA/cm2. The current density in this work meets the DOE’s 2020 target of 1 µA/cm2. Electrical conductivity is inversely proportional to the corrosion resistance. The significant improvement in the corrosion resistance of the a-C:H film was mainly attributed to the increased sp3 element and nanocrystalline TiC phase in the penetration layer. As a result, the a-C:H film-coated titanium at CH4/H2 = 1:0 with improved anti-corrosion behavior creates a great potential for PEMFC bipolar plates.

Influence of EDTA-2Na Concertration on the Microstructure and Corrosion Behaviors of Mg-Al-Y Alloy

2015 ◽  
Vol 727-728 ◽  
pp. 201-204
Author(s):  
Yun Long Zhang ◽  
Mu Qin Li ◽  
Ping Liao ◽  
Yu Min Zhang
Keyword(s):  
Corrosion Resistance ◽  
Electrolyte Solution ◽  
Oxidation Process ◽  
Corrosion Current ◽  
Positive Potential ◽  
Micro Arc Oxidation ◽  
Corrosion Behaviors ◽  
Oxidation Technology ◽  
Structural Surface ◽  
Polarisation Measurements

In this paper,the micro-arc oxidation technology were utilized to fabricated the oxidation coating in order to resolve the corrosion resistance of the Mg-Al-Y alloy. The EDTA-2Na solution was introduced into the electrolyte solution for improving the coating corrosion properties.After the micro-arc oxidation process, phase structural, surface morphology and corrosion resistance of the MAO coating of Mg-Al-Y alloy were performed by XRD, SEM and Potentiodynamic polarisation measurements. The introduce of EDTA-2Na in the electrolyte solution improve the positive potential and reduced the corrosion current, which would improve the corrosion resistance properties of the Mg-Al-Y alloy.

Effects of Y Alloying on Thermal Stability and Corrosion Resistance of Cu-Zr-Al Metallic Glass

2013 ◽  
Vol 850-851 ◽  
pp. 62-65
Author(s):  
Yi Liu ◽  
Yan Fang Wang ◽  
Li Jun Xiao ◽  
Ming Xing Liu ◽  
Zhi Qiang Shi
Keyword(s):  
Thermal Stability ◽  
Corrosion Resistance ◽  
Base Alloy ◽  
Amorphous State ◽  
Corrosion Current ◽  
Casting Method ◽  
Glass Forming ◽  
Minor Addition ◽  
Corrosion Behaviors ◽  
Thermal Stability Of

The (Cu50Zr45Al5)100-XYX(x=0, 1, 2, and 3) alloys samples were prepared by copper mold suction casting method. The effect of the addition of Y on the structure, glass-forming ability, thermal stability and corrosion behaviors of the base BMG (Cu50Zr45Al5) were investigated by means of XRD, DSC, DTA and electrochemical polarization. The results showed that Cu10Zr7and Zr2Cu phases are precipitated when Y addition exceeds 3at%, otherwise the alloys are fully amorphous state. Minor addition Y improved the thermal stability of the base alloy. The corrosion resistance of BMG alloy is deteriorated in 3.5% NaCl solution with addition of Y element as indicated by the corrosion potential and corrosion current density.

In situ and ex situ characterization of a Fe-Cr-Ni alloy in mouthwashes and Hank’s solution

2008 ◽  
Vol 62 (3) ◽  
Author(s):  
Dane Cestarolli ◽  
Valéria Alves ◽  
Luís Silva
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Techniques ◽  
Passive Layer ◽  
Chloride Ions ◽  
Localized Corrosion ◽  
Ex Situ ◽  
Ni Alloy ◽  
Hank’S Solution

AbstractThe aim of the present study was to classify the surface oxide layers formed on a Fe-Cr-Ni alloy according to their corrosion resistance in Hank’s solution and mouthwashes by SEM and electrochemical techniques. The SEM micrographs showed the presence of localized corrosion and the polarization curves showed that the passive layer is less stable in the presence of Hank’s solution than of mouthwashes, as a result of the presence of chloride ions.

scholarly journals Roles of Graphene Additives in Optimizing the Microstructure and Properties of Ni–Cr–Graphene Coatings

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 104 ◽  
Author(s):  
Liang Meng ◽  
Qinyou Hu ◽  
Chaojian Shi ◽  
Changhai Huang
Keyword(s):  
Corrosion Resistance ◽  
Crystallite Size ◽  
Rietveld Refinement ◽  
Microstructure Evolution ◽  
Corrosion Current ◽  
Micro Hardness ◽  
Electrodeposition Technique ◽  
Graphene Coating ◽  
Order Of Magnitude ◽  
Corrosion Behaviors

The electrodeposition technique was used to fabricate graphene and Cr particle-reinforced Ni–Cr–graphene coatings. The Rietveld refinement was utilized to analyze the microstructure of Ni deposits in the coatings. The properties including micro-hardness and corrosion behaviors of the coatings were also tested. Results showed that the addition of graphene particles contributed to the dendrite like structure on the surface of the Ni–Cr–graphene coating. The crystallite size and [200] texture of the Ni deposits in the Ni–Cr–graphene coatings were significantly decreased by the graphene particles. The crystallite size of 149.8 nm in the Ni-25–Cr-0–graphene coating was reduced to 35 nm in the Ni-25–Cr-8–graphene coating due to the addition of 8 g/L graphene to the electrolyte. The microstructure evolution of the Ni–Cr–graphene coatings brought about an enhancement in micro-hardness and corrosion resistance of the coatings. The micro-hardness of the coatings was improved from 260.1 HV0.2 of the pure Ni coating to 285.9 HV0.2 of the Ni-25–Cr-0–graphene coating and continually to 461.8 HV0.2 of the Ni-25–Cr-8–graphene coating. In corrosion solution (3.5 wt.% NaCl), the corrosion current (6.22 μA/cm2) of the Ni-25–Cr-0–graphene coating could be decreased by about an order of magnitude through the addition of graphene particles, which was 0.33 μA/cm2 for the Ni-25–Cr-8–graphene coating.

Research on Resistance Spot Welding Property of Hot-Stamping Quenched Steel Sheets

2014 ◽  
Vol 1063 ◽  
pp. 120-125
Author(s):  
Jun Ping Zhang ◽  
Yi Feng ◽  
Lei Feng Song ◽  
Guang Yao Wang ◽  
Qing Sheng Jin
Keyword(s):  
Mechanical Property ◽  
Hot Stamping ◽  
Welding Current ◽  
Welding Parameters ◽  
Good Mechanical Property ◽  
Welding Time ◽  
Steel Sheets ◽  
Power Frequency ◽  
Quenched Steel ◽  
Hot Stamping Steel

22MnMoB hot-stamping quenched steel sheets were well welded together by power frequency spot welder with optimization of relevant welding parameters in this paper. According to the experiment results of welding spatter, maximum shearing force and the size of nugget, the effects of welding current, welding time and electrode pressure on weld property were advanced. The results show that while welding current, welding time and electrode pressure are respectively set as 6.0~6.5kA, 0.5~0.7s and 4~7kN, the weld exhibits good mechanical property. The nugget diameter appears approximate linear relationship with mechanical property of weld and determines the fracture model of welds. The novel hot stamping steel sheets exhibit good welding property. The optimizing welding parameters can be used to instruct the practical production.

scholarly journals A New Approach in Modifying Polymeric Coatings to Increase Corrosion Resistance Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Alisina Toloei ◽  
Sanam Atashin ◽  
Mohammad Ebrahim Bahrololoom
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Open Circuit ◽  
Polymeric Coatings ◽  
Protective Properties ◽  
Clay Nanoparticles ◽  
Steel Sheets ◽  
Corrosive Environments ◽  
Modified Epoxy

In this study, carbon steel sheets were coated with a modified epoxy coating. The urea-modified montmorillonite clay nanoparticles were added to a DGEBA epoxy resin in different contents and then applied to the surfaces. The corrosion resistance of the coated samples was determined by electrochemical techniques (open circuit potential and linear polarization) in 3.5 wt% NaCl solutions at room temperature and 80°C. Electrochemical impedance spectroscopy (EIS) evaluated the properties of polymer-coated metals and their changes during the exposure to corrosive environments. Scanning electron microscopy (SEM) was used to characterize the coatings. An improvement of protective properties of epoxy coatings with an optimal percentage of the modified clay in comparison with pure epoxy was achieved.

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