scholarly journals Influence of Alloy Content on Microstructure and Corrosion Resistance of Zn-based Alloy Coated Steel Product

2020 ◽  
Vol 58 (3) ◽  
pp. 169-174 ◽  
Author(s):  
Jae-Won Lee ◽  
Sung-Jin Kim ◽  
Min-Suk Oh

The effects of alloy composition on the coating structure and corrosion resistance of hot-dip Znbased alloy coated steel products were investigated. Zn-based alloy coating layers with different Al and Mg compositions were fabricated using a batch-type galvanizing simulator. Various intermetallic compounds including Zn, Zn/MgZn<sub>2</sub> binary eutectic, Zn/Al binary eutectoid and Zn/Al/MgZn<sub>2</sub> ternary eutectic phases were formed in the coating layer. The surface and cut-edge corrosion resistance of the Zn-based alloy coating were superior to those of the Zn coating. Zn-based alloy coating containing 15% Al and 3% Mg showed the best corrosion resistance, with red rust formed on the flat surface after 120 hours in the salt spray test. The corrosion products of the Zn-based alloy coating consisted of Simonkolleite (Zn<sub>5</sub>(OH)<sub>8</sub>Cl<sub>2</sub>·H<sub>2</sub>O), Hydrozincite (Zn<sub>5</sub>(CO<sub>3</sub>)<sub>2</sub>(OH) and zinc oxide (ZnO). Al-containing corrosion products, Zn<sub>2</sub>Al(OH)<sub>6</sub>Cl<sub>2</sub>·H<sub>2</sub>O and Al<sub>2</sub>O<sub>3</sub>, were formed when more than 5 wt% Al was added. Al-containing corrosion products improved the corrosion resistance of the flat surface of Zn-based alloy coating, but did not affect corrosion resistance in the cut-edge area.

2013 ◽  
Vol 834-836 ◽  
pp. 601-608 ◽  
Author(s):  
She Ming Jiang ◽  
Chong Feng Yue ◽  
Qi Fu Zhang

Hot Dip Zn-6Al-3Mg-0.2Si coating steel sheet was prepared in laboratory by Hot-dip Galvanizing Simulator produced by National Engineering Lab of Advanced Coating Technology for Metal Materials. The surface and cross sectional microstructure of the samples were analyzed by using SEM and EDS. Hot dip Zn coated, 55Al-43.3Zn-1.6Si and Zn-6Al-3Mg-0.2Si coated steel sheet samples were exposed to standardized salt spray test. The Zn-6Al-3Mg-0.2Si coating and its erode production were investigated by XRD. The results showed that the hot dip Zn-6Al-3Mg-0.2Si coating had better corrosion resistance than ordinary galvanized layer.


2019 ◽  
Vol 66 (6) ◽  
pp. 819-826
Author(s):  
Khashayar Tabi ◽  
Mansour Farzam ◽  
Davood Zaarei

Purpose Potassium silicate sealer was applied on solvent-cleaned, acid-pickled, dacromet-coated steel to improve its corrosion resistance. The purpose of this paper is to study the corrosion behavior of dacromet-coated steel. Design/methodology/approach Potassium silicate sealer was applied on solvent-cleaned, acid-pickled, dacromet-coated steel to improve its corrosion resistance. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and salt spray were carried out. SEM was used to study the morphological appearance of the surface. Findings The EIS behavior indicated that solvent-cleaned dacromet-coated steel sealed with potassium silicate showed that the corrosion current density was 2.664E − 5 A.cm2 which was reduced to 8.752E − 6 A.cm2 and the corrosion rate, which was 2.264E − 2 mm.year−1, was reduced to 7.438E − 3 mm.year−1 in NaCl 3.5 wt.per cent. EIS was used in NaCl 3.5 wt.%, and the Bode plot characteristics showed that the corrosion protection of solvent-cleaned, dacromet-coated steel was enhanced when sealed with potassium silicate. The EDS results of salt-sprayed, solvent-cleaned samples after 10 days indicated that the main corrosion products are composed of SiO2, ZnO and Al2O3. Research limitations/implications The detection of Li element in EDS was not possible because of the device limitation. Originality/value The current paper provides new information about the sealing properties of potassium silicate and its effects on the corrosion resistance of dacromet coating, which is widely used in many industries such as the automobile industry.


2005 ◽  
Vol 91 (9) ◽  
pp. 700-705 ◽  
Author(s):  
Masamitsu MATSUMOTO ◽  
Masanari KIMOTO ◽  
Akito SAKODA ◽  
Takeo KUDOU

2011 ◽  
Vol 189-193 ◽  
pp. 1284-1287
Author(s):  
Bo Gao ◽  
Shi Wei Li ◽  
Yi Hao ◽  
Gan Feng Tu ◽  
Liang Hu ◽  
...  

A new hot dip Zn-5%Al-0.3%Mg alloy coating was performed on cold rolled common steel. The hot-dip process was executed by self-made hot dip galvanising simulator (China patent, No.201010160353). The corrosion resistance of alloy-coated steels was detected by neutral salt spray test . SEM and EDS test results demonstrate that Mg is mainly distributed in the crystal boundary. XRD test results shows corrosion product of Zn-5%Al-0.3%Mg alloy coating is mainly Zn5(OH)8Cl2•H2O. The characteristic of Zn5 (OH)8Cl2•H2O is dense and insoluble, so it is protective. In order to study the anticorrosion mechanism, all the tests of the Zn-5%Al-0.3%Mg alloy were carried out with Zn-5%Al coating together.


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 552
Author(s):  
Changyao Ouyang ◽  
Qiaofeng Bai ◽  
Xianguo Yan ◽  
Zhi Chen ◽  
Binhui Han ◽  
...  

In this paper, the corrosion performance of a laser cladding Fe-based alloy coating on the surface of 27SiMn steel was studied. The Fe-based alloy coating was prepared on a 27SiMn steel surface by high-speed laser cladding. The microstructure, morphological characteristics, element content, and phase composition of the cladding layer were analyzed by an optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and X-ray diffractometer (XRD), respectively. The corrosion resistance of the 27SiMn substrate and Fe-based coating in different corrosive environments was tested through an electrochemical experimental station, a salt spray corrosion test box, and an immersion experiment. The Fe-based alloy cladding layer is mainly composed of a-Fe, M7C3, M2B, and Cr3Si. The cladding layer structure forms planar, cellular, dendrite, and equiaxed dendrite during rapid solidification. The corrosion potential of the cladding layer is higher than that of the substrate, and the arc radius of the cladding layer is larger than that of the substrate. After salt spray corrosion, a large number of red and black corrosion products appeared on the surface of the substrate; the surface of the cladding layer sample was still smooth, and the morphology was almost unchanged. The weight loss results of the cladding layer and 27SiMn matrix after 120 h of immersion are 0.0688 and 0.0993 g·cm−2, respectively. The weight loss of the cladding layer is 30.7% less than that of the matrix. Conclusion: Laser cladding an Fe-based alloy coating on the surface of 27SiMn has better corrosion resistance than the substrate, which improves the corrosion resistance of hydraulic supports.


2010 ◽  
Vol 59 (12) ◽  
pp. 468-477 ◽  
Author(s):  
Masamitsu Matsumoto ◽  
Nobuhiro Okada ◽  
Katsuhiro Nishihara ◽  
Masanari Kimoto ◽  
Takeo Kudo ◽  
...  

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Shiwei Li ◽  
Bo Gao ◽  
Ganfeng Tu ◽  
Yi Hao ◽  
Liang Hu ◽  
...  

A new type of hot-dip Zn-5Al-0.5Mg-0.08Si and Zn-5Al alloy coatings was performed on the cold rolled common steel. The hot-dip process was executed by self-made hot-dip galvanising simulator. SEM and EDS test results demonstrated that Mg was mainly distributed in crystal boundaries. XRD test results showed that the corrosion product of Zn-5Al-0.5Mg-0.08Si alloy coating was almost Zn5(OH)8C12⋅H2O. The features of Zn5(OH)8C12⋅H2O are low electric conductivity, insolubility and good adhesion.The corrosion resistance of alloy-coated steels was detected by neutral salt spray test. The microstructural characterization of the coating surface after neutral salt spray test and removing the corrosion products revealed that the corrosion process of Zn-5Al-0.5Mg-0.08Si coating was uniform and the coating surface was almost flat. As a result, the corrosion resistance of Zn-5Al-0.5Mg-0.08Si coating has a remarkable improvement with a factor of 9.2 compared with that of Zn-5Al coating.


2011 ◽  
Vol 399-401 ◽  
pp. 2072-2078
Author(s):  
Miao Lou ◽  
Yu Feng Lu ◽  
Chun Lin Ma ◽  
Yong Le Hu ◽  
Meng Zhou ◽  
...  

Zn、Al alloy coatings were prepared by high velocity arc spraying technology on 16MnR steel substrates, With the design salt spray test, Study on the corrosion resistance of the Zn、Al alloy coating in the grotto environment. The porosity of the metal coating and the compact of the corrosion are infection on the corrosion resistance of the coating. Al coating and Zn/Al(300/100) coating corrosion resistance better than others on 16MnR steel.


Sign in / Sign up

Export Citation Format

Share Document