scholarly journals Development of PosMAC® Steel and Its Application Properties

2021 ◽  
Vol 59 (9) ◽  
pp. 613-623
Author(s):  
Il-Ryoung Sohn ◽  
Tae-Chul Kim ◽  
Gwang-Il Ju ◽  
Myung-Soo Kim ◽  
Jong-Sang Kim
Keyword(s):  
Corrosion Protection ◽  
Surface Friction ◽  
Chemical Compositions ◽  
Corrosion Performance ◽  
Corrosion Properties ◽  
Friction Resistance ◽  
Superior Surface ◽  
Coated Surfaces ◽  
Corrosive Environments ◽  
Coating Weight

PosMAC® is a hot dipping Zn-Mg-Al coated steel sheet developed by POSCO. PosMAC®3.0 shows excellent anti-corrosion performance and is suitable for construction and solar energy systems in severe corrosive environments. PosMAC®1.5 has a superior surface quality and is preferred for automotive and home appliances. The advanced anti-corrosion properties of PosMAC® comes from a dense corroded layer which forms on coated surfaces, compared with traditional Zn coatings such as GI, GA and EG. PosMAC® steels show superior corrosion protection compared to GI coatings in cyclic corrosion tests, despite an approximate 30% reduction in coating weight. The PosMAC® has excellent application properties for the arc welding of automotive chassis. It has a heat resistance that is more robust than the GI coating, and maintains excellent corrosion protection near the welds of the chassis. Zn-Mg-Al coatings, whose chemical compositions are similar to PosMAC® coatings, have very low surface friction properties compared to the GI coating. The friction coefficient of PosMAC® is stabilized to 0.09~0.11. In contrast, the GI coating showed higher friction coefficients of 0.2~0.3 in the repeated friction test. PosMAC® would be appropriate for complex forming parts with less galling, given these low friction resistance properties. It is expected that the industrial demand for PosMAC® steel will increase in the near future, thanks to its Zn saving and high anti-corrosion performance.

Corrosion Resistance of Nd-Fe-B Magnets Coated with Polypyrrole Films

2006 ◽  
Vol 530-531 ◽  
pp. 111-116
Author(s):  
M.C.E. Bandeira ◽  
F.D. Prochnow ◽  
Isolda Costa ◽  
César V. Franco
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Nacl Solution ◽  
Corrosion Performance ◽  
Low Frequencies ◽  
Polypyrrole Films ◽  
Phosphate Ions ◽  
Polypyrrole Film ◽  
Corrosive Environments ◽  
Magnet Surface

Nd-Fe-B magnets present outstanding magnetic properties. However, due to their low corrosion resistance, their applications are limited to non-corrosive environments. Nowadays, significant efforts are underway to increase the corrosion resistance of these materials, through the use of coatings. Herein are presented the results of a study on the corrosion resistance of Nd-Fe-B magnets coated with polypyrrole (PPY). The electrochemical behavior of coated and uncoated magnets has been studied by Electrochemical Impedance spectroscopy (EIS) in synthetic saliva. The results were compared to previous investigations, which were carried out under similar conditions, in Na2SO4 and NaCl solutions. In sulphate solution, the corrosion resistance of the PPY-coated magnet was 3 times larger (1600 .cm2) than that of uncoated magnet (500 .cm2). In NaCl solution, however, the corrosion resistance of coated and uncoated magnets were very similar (250 .cm2). In synthetic saliva, both the uncoated and coated magnets presented good corrosion performance (1940 .cm2). Such behavior can be attributed to the phosphate ions in saliva, which play a role as corrosion inhibitor, producing phosphating, at least partially, of the magnet surface. The PPY-coated magnets presented a strong diffusional control from moderate to low frequencies, caused by the polypyrrole film. The thicker PPY film increased the corrosion resistance of the magnet in synthetic saliva.

Corrosion Protection Coatings from Size-Specified Graphene Oxide

2020 ◽  
Vol 981 ◽  
pp. 29-33
Author(s):  
Nurul Huda Abu Bakar ◽  
Jamil Ismail ◽  
Kwok Feng Chong
Keyword(s):  
Graphene Oxide ◽  
Corrosion Protection ◽  
Surface Texture ◽  
Copper Substrate ◽  
Smooth Surfaces ◽  
Nacl Solution ◽  
Corrosion Performance

Corrosion performance of graphene oxide (GO) coatings from different sheets sizes in 3.5 wt% NaCl solution was investigated. The GO dispersion was subjected to 5 and 10 hours of ultrasonication before electrophoretically deposited (EPD) onto the copper substrate. It was found that the EPD-GO coating from smaller sheets (10h ultrasonication) possess hydrophobic, thinner film and smooth surfaces. It is suggested that the corrosion performance of the coating from smaller GO sheets is improved due to the surface texture and compactness of the coating as compared to the larger GO sheets.

scholarly journals Acrylate-Based Hybrid Sol-Gel Coating for Corrosion Protection of AA7075-T6 in Aircraft Applications: The Effect of Copolymerization Time

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 948 ◽  
Author(s):  
Peter Rodič ◽  
Romana Cerc Korošec ◽  
Barbara Kapun ◽  
Alenka Mertelj ◽  
Ingrid Milošev
Keyword(s):  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Condensation Reaction ◽  
Energy Dispersive Spectrometer ◽  
Sol Gel ◽  
Gel Permeation Chromatography ◽  
Corrosion Attack ◽  
Scanning Calorimetry ◽  
Corrosion Properties ◽  
Pressure Differential Scanning Calorimetry

Pre-hydrolysed/condensed tetraethyl orthosilicate (TEOS) was added to a solution of methyl methacrylate (MMA) and 3-methacryloxypropyltrimethoxysilane (MAPTMS), and then copolymerised for various times to study the influence of the latter on the structure of hybrid sol-gel coatings as corrosion protection of aluminium alloy 7075-T6. The reactions taking place during preparation were characterised using real-time Fourier transform infrared spectroscopy, dynamic light scattering and gel permeation chromatography. The solution characteristics were evaluated, using viscosimetry, followed by measurements of thermal stability determined by thermogravimetric analysis. The optimal temperature for the condensation reaction was determined with the help of high-pressure differential scanning calorimetry. Once deposited on 7075-T6 substrates, the coatings were evaluated using a field emission scanning electron microscope coupled to an energy dispersive spectrometer to determine surface morphology, topography, composition and coating thickness. Corrosion properties were tested in dilute Harrison’s solution (3.5 g/L (NH4)2SO4 and 0.5 g/L NaCl) using electrochemical impedance spectroscopy. The copolymerization of MMA and MAPTMS over 4 h was optimal for obtaining 1.4 µm thick coating with superior barrier protection against corrosion attack (|Z10 mHz| ~ 1 GΩ cm2) during three months of exposure to the corrosive medium.

scholarly journals Graphene Oxide/Polyaniline Nanocomposites Used in Anticorrosive Coatings for Environmental Protection

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1215
Author(s):  
Shuanqiang Yang ◽  
Shu Zhu ◽  
Ruoyu Hong
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Impedance ◽  
In Situ Polymerization ◽  
Barrier Properties ◽  
Living Environment ◽  
Metal Corrosion ◽  
Corrosion Performance ◽  
Corrosion Properties ◽  
Anticorrosive Coatings ◽  
Vis Spectroscopy

In recent years, metal corrosion causes serious threats to the economy of the world and the living environment. Hence, it is very important to seek non-toxic and environmentally friendly materials with metal anti-corrosion properties for the sustainable development of society. The barrier properties of graphene oxide (GO) and the special electrochemical property of polyaniline (PANI) can significantly improve the corrosion resistance of metals. Herein, we developed an in-situ polymerization method to prepare graphene oxide/polyaniline (GO/PANI) nanocomposites with unique anti-corrosion properties. The obtained GO/PANI nanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermalgravimetric analysis, UV–vis spectroscopy and scanning electron microscopy. The as-prepared composite materials were uniformly dispersed in epoxy resin to prepare anticorrosive coatings and coated on the surface of steel. The anti-corrosion performance of the coatings was measured by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization technique. The EIS results showed that the total impedance of epoxy/GO/PANI coatings is greater than epoxy/PANII coatings, and the impedance module value can reach 8.67 × 108 Ω·cm2. In general, it is concluded that the anti-corrosion performance of GO/PANI coating is significantly higher than PANI coating and pure GO coating.

THE CORROSION BEHAVIOR OF WEATHERING STEEL UNDER DIFFERENT CORROSIVE ENVIRONMENTS

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Takahiro Utsumi ◽  
Toshihiko Aso
Keyword(s):  
Sodium Chloride ◽  
Exponential Function ◽  
Steel Surface ◽  
Weathering Steel ◽  
Corrosion Performance ◽  
Iron Transfer ◽  
Transfer Resistance ◽  
Chloride Solutions ◽  
Sodium Chloride Solutions ◽  
Corrosive Environments

Weathering steel is a kind of steel that can reduce the corrosion rate by generating a dense protective rust on the steel surface that exerts anti-corrosion performance. Exposure tests of weathering steel with saltwater spraying were performed under three different conditions. When the consistency of sodium chloride solutions was small (0.5% and 1.0%), the effect of rain rinse was observed. However, large consistencies of sodium chloride solutions provided small differences in rust thickness between open air and under roof conditions. From the results of iron transfer resistance measurements, it was observed that protective rust was generated only in a few cases. This result indicated that generation of protective rust was strongly dependent on the corrosive environment. From the results of exposure tests, it became clear that the change of rust thickness with time can be estimated as an exponential function. The constants in the exponential function can be expressed as a function of consistency of sodium chloride solutions.

Determination of Mechanical and Corrosion Properties of Boride Coating on P91 Steel

2010 ◽  
Vol 438 ◽  
pp. 89-96
Author(s):  
Haidar Omar ◽  
Nikolaos Michailidis ◽  
Stefanos Skolianos ◽  
Azarias Mavropoulos ◽  
Sofia Tsipas ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
High Performance ◽  
Protective Coatings ◽  
Salt Spray ◽  
Fatigue Properties ◽  
Boride Coating ◽  
Corrosion Properties ◽  
P91 Steel ◽  
The One ◽  
Corrosive Environments

In many applications, even high-performance alloys have to be covered with protective coatings, providing higher corrosion and oxidation resistance, as compared to the alloy itself. This study investigates the feasibility to apply boron coatings on P91 steel by pack cementation process, to increase the steel durability in oxidative and corrosive environments, as well as its mechanical strength. Micro-indentation and the coating impact test were used to characterize the hardness and fatigue properties of the film respectively. The coating corrosion resistance versus the one of the uncoated P91 steel was tested in a salt spray chamber. The coating performance was characterized by optical and scanning electron microscopy to check the consistency of the coated and uncoated surfaces and the oxidation extend. The results show an increased film strength, good fatigue performance and adequate corrosion resistance.

Selective Radiation Properties of Particulate Coatings

1963 ◽  
Vol 85 (3) ◽  
pp. 213-220 ◽  
Author(s):  
D. A. Williams ◽  
T. A. Lappin ◽  
J. A. Duffie
Keyword(s):  
Optical Properties ◽  
Radiation Properties ◽  
High Fraction ◽  
Energy Absorbers ◽  
Coated Surfaces ◽  
Particulate Coatings ◽  
Aluminum Substrates ◽  
Coating Weight ◽  
Theoretical Considerations ◽  
Better Than

The variation with wavelength of thermal radiation properties of coated surfaces is important for solar energy absorbers and in other applications, and depends on the optical properties of the coating material and the substrate, and on the structure of the coating. Theoretical considerations indicate that, for homogeneous coatings, the good optical properties of semiconductors can be improved if the coating contains a high fraction of voids. This improvement has been shown by experimental particulate PbS coatings which are not homogeneous; the selective properties of particulate coatings are better than those calculated for solid coatings at the same coating weight. PbS coatings on aluminum substrates show absorptances for solar radiation of 0.9 and long wave emittance of 0.2 to 0.3. The feasibility of selective paints has been demonstrated; PbS can be mixed with a transparent binder, silicone, to make a paint which shows a good degree of selectivity, and absorptances of 0.9 and emittances less than 0.4 have been obtained.

Pyrrole-Based Silane Primer for Corrosion Protection of Commercial AA 2024 T3

2008 ◽  
Vol 38 ◽  
pp. 14-26 ◽  
Author(s):  
Monica Trueba ◽  
Stefano P. Trasatti
Keyword(s):  
Surface Treatment ◽  
Corrosion Protection ◽  
Layer Structure ◽  
Film Deposition ◽  
Corrosion Performance ◽  
Alternative Approach ◽  
Aa 2024

An alternative approach was developed for surface treatment of as-received commercial AA 2024 T3 by using a pyrrole-based silane (SiPy). For film deposition, just one immersion step is enough, followed by curing. SiPy layer structure contains both polysiloxane bonds and pyrrole oligomers, with some degree of doping, giving a highly coherent layer. The superior film quality with respect to simple polysiloxane, is probably the main reason for the better corrosion performance obtained for SiPy on 2024.

Sign in / Sign up

Export Citation Format

Share Document