Electrochemical Behavior of Mg in H3PO4 and Phosphating Solution

2014 ◽  
Vol 1081 ◽  
pp. 318-321 ◽  
Author(s):  
Dao Bing Huang ◽  
Yuan Qiang Tu ◽  
Ting Hu ◽  
Guang Ling Song ◽  
Xing Peng Guo

The electrochemical behavior of pure Mg in H3PO4 acid (0.42 M) and phosphating solution (0.42 M H3PO4+0.34 M ZnO) was investigated through electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curve and XRD measurements. The results show that Mg has higher corrosion resistance in the phosphating solution than that in the H3PO4 acid which may be due to the relative protective phosphating film on the surface.

Author(s):  
Sajjad Sadeghi ◽  
Hadi Ebrahimifar

Abstract The use of ceramic particles in the matrix of alloy coatings during the electroplating process has received considerable attention. These particles can create properties such as high corrosion resistance, insolubility, high-temperature stability, strong hardness, and self-lubrication capability. Herein, an Ni–P–W–TiO2 coating was deposited on an AISI 304L steel substrate using the electroplating method. Electroplating was performed at current densities of 10, 15, 20, and 25 mA · cm–2, and the effect of current density on microstructure, corrosion behavior, and wear behavior was investigated. The coatings were characterized by means of scanning electron microscopy. To investigate corrosion resistance, potentiodynamic polarization and electrochemical impedance spectroscopy tests were performed in a 3.5% NaCl aqueous solution. A pin-on-disk test was conducted to test the wear resistance of uncoated and coated samples. Sample micro-hardness was also measured by Vickers hardness testing. Examination of the microstructure revealed that the best coating was produced at a current density of 20 mA · cm–2. The results of potentiodynamic polarization and electrochemical impedance spectroscopy tests were consistent with microscopic images. The coating created at the current density of 20 mA · cm–2 had the highest corrosion resistance compared to other coated and non-coated samples. Furthermore, the results of the wear test showed that increasing the current density of the electroplating path up to 20 mA · cm–2 enhances micro-hardness and wear resistance.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaoxing Yan ◽  
Yunting Cai ◽  
Rong Lu ◽  
Tetsuo Miyakoshi

This study investigated the effects of aluminum (Al) mass fraction on the performance of an epoxy-lacquer based coating. The conductivity increased and IR emissivity and gloss decreased with increased Al mass fraction. When the Al mass fraction was decreased from 40% to 30%, the adhesion and impact strength of epoxy-lacquer based coatings increased and were grade 1 and 50 Kg·cm, respectively. When the Al mass fraction was decreased to 10%, the mechanical properties of epoxy-lacquer based coatings decreased. Potentiodynamic polarization and electrochemical impedance spectroscopy of coatings showed that epoxy-lacquer based coating with 30% Al mass fraction has the best corrosion resistance and the lowest porosity. The epoxy-lacquer based coating with the best stability was that of 30% Al mass fraction. Comparing epoxy-lacquer based coating with polyurethane based coating, the epoxy-lacquer based coating presents not only lower emissivity and gloss but also better mechanical properties and corrosion resistance.


2011 ◽  
Vol 418-420 ◽  
pp. 1097-1101 ◽  
Author(s):  
Tao Zhang ◽  
Hong Yang Jing ◽  
Yong Dian Han ◽  
Lian Yong Xu

The electrochemical behavior of corrosion resistance alloys (316L SS, 2205 DSS and Inconel 625) was carried out at ambient temperature in 3.5% NaCl solution using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) techniques. Some significant characterization parameters such as Ecorr, Eb, Icorrand △E in polarisation curves were analyzed and compared to reveal the corrosion resistance of corrosion resistance alloys. The ZsimpWin software was utilized to discuss the Nyquist plots of various corrosion resistance alloys. The result shows that the corrosion resistance of the corrosion resistance alloys in 3.5% NaCl solution at ambient temperature follows the sequence: Inconel 625> 2205 DSS > 316L SS.


2021 ◽  
Vol 353 ◽  
pp. 01010
Author(s):  
Lun Nie ◽  
Min Zhu ◽  
Shirun Tu ◽  
Kefeng Yuan ◽  
Kexin Lu

39SiCrVTiA spring steel is heat-treated and compared with the existing high-strength spring steels 60Si2CrVA and SAE9254 for electrochemical impedance spectroscopy (EIS), polarization curve and slow strain rate testing (SSRT). The test results of electrochemical impedance spectroscopy (EIS), polarization curve show that the corrosion resistance of 60Si2CrVA was the best, followed by that of SAE9254 and 39SiCrVTIA.However, the test results of the SSRT test show that the three spring steels in 5% NaCl solution possess high SCC susceptibility. The SCC susceptibility of 39SiCrVTiA steel is slightly lower and the stress corrosion ability is better than the other two steels which may be related to its containing Ti, V elements and lower carbon content.


RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25314-25333
Author(s):  
Mai A. Khaled ◽  
Mohamed A. Ismail ◽  
Ahmed. A. El-Hossiany ◽  
Abd El-Aziz S. Fouda

This study targets the investigation of three pyrimidine derivatives (MA-1230, MA-1231, MA-1232) for the prevention of corrosion on copper in 1 M HNO3via weight loss (WL), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) techniques.


2014 ◽  
Vol 789 ◽  
pp. 495-500
Author(s):  
Bing Ying Wang ◽  
Qing Hao Shi ◽  
Wen Long Zhang

The polyurea was modified by adding different amounts of nanometer ZnO. The corrosion behavior of polyurea/primer composite coating system in wet-dry cyclic environment of 3.5% NaCl solution was studied by using the Electrochemical Impedance Spectroscopy (EIS) measurement and adhesion test technology. The experimental result showed that, different mass fractions of nanometer ZnO had different influences on the corrosion resistance property of coating. When the mass fraction of nanometer ZnO was 5%, the composite coating had the largest protective action. The corrosion resistance property of nanometer ZnO can be improved by increasing the density of polyurea coating, however, the corrosion resistance property of polyurea coating will be weakened in case of exceeding the critical adding amount.


CORROSION ◽  
10.5006/3254 ◽  
2019 ◽  
Vol 75 (11) ◽  
pp. 1339-1353
Author(s):  
Maryam Eslami ◽  
Flavio Deflorian ◽  
Caterina Zanella

The electrochemical behavior of a low silicon aluminum alloy cast by the conventional and rheo-high-pressure die cast processes is evaluated using polarization test and electrochemical impedance spectroscopy in 0.01 M, 0.05 M, 0.1 M, and 0.6 M sodium chloride solutions. Compared to the conventional high-pressure die cast process, rheocasting introduces some alterations in the microstructure including the presence of aluminum grains with different sizes, formed at different solidification stages. According to the results of the anodic polarization test, conventional cast and rheocast samples show similar breakdown potentials. However, the rheocast samples present enhanced oxygen reduction kinetics compared to the conventional cast sample. Based on scanning electron microscopy examinations, localized microgalvanic corrosion is the main corrosion mechanism for both alloys and it initiates at the interface of aluminum with iron-rich intermetallic particles which are located inside the eutectic regions. The corrosion further develops into the eutectic area. Although the rate of the cathodic reaction can be influenced by the semisolid microstructure, according to the results of anodic polarization and electrochemical impedance spectroscopy tests, the corrosion behavior is not meaningfully affected by the casting process.


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