Variation in Corrosion Resistance of Trivalent Chromate Coating Depending on Type of Zinc Plating Bath

2006 ◽  
Author(s):  
Haruyuki Watanabe ◽  
Masahiro Oshio ◽  
Naohiro Kunieda
CORROSION ◽  
10.5006/3760 ◽  
2021 ◽  
Author(s):  
Thanyalux Wanotayan ◽  
Tongjai Chookajorn ◽  
Sirikarn Sattawitchayapit ◽  
Piya Khamsuk ◽  
Kanokwan Saengkiettiyut ◽  
...  

The effects of alkaline non-cyanide zinc plating bath formulation on the plating characteristics and deposit properties are investigated. Scanning electron microscope and X-ray diffractometer are used to study the surface morphology and texture of the zinc deposits respectively. Uniform and compact coatings with a dominant (110) texture are obtained for all of the bath formulations. Nevertheless, significant differences in surface morphology and relative preferences for the (110) and (100) planes were found to result from the concentrations of zinc and sodium hydroxide in the bath. Electrochemical impedance spectroscopy and potentiodynamic polarization scan were employed to evaluate the corrosion resistance. The coatings with a moderate Zn (8-11 g/L) and controlled NaOH (120 g/L) contents show good corrosion resistance, with the corrosion current and corrosion rate being the lowest at 8 g/L of Zn and 120 g/L of NaOH. The ratio of texture coefficient, morphology, and compressive residual stress from different bath composition contribute to the corrosion resistant property. The findings from this work should provide useful information of electrogalvanized zinc coatings with enhanced corrosion resistance.


2011 ◽  
Vol 399-401 ◽  
pp. 2055-2060
Author(s):  
Ji Bo Jiang ◽  
Wei Dong Liu ◽  
Lei Zhang ◽  
Qing Dong Zhong ◽  
Yi Wang ◽  
...  

Ni–B4C composite coatings on carbon steel substrates with various contents of B4C nano-particulates were prepared by electrodeposition in Ni plating bath containing B4C nano-particulates. Microhardness, Scanning Electron Microscopy (SEM), Tafel polarization and Electrochemical Impedance Spectroscopy (EIS) measurements were used to compare pure nickel coatings and Ni–B4C composite coatings. Pure Ni coating microhardness is lower than that of Ni–B4C coatings and the microhardness of the composite coatings increases with the increase of the content of B4C nano-particulates. The effects of various contents of B4C nano-particulates on the corrosion resistance were investigated and it was found that the best anti–corrosion property of Ni–B4C composite coatings is at 6 g/L B4C in the bath formulation.


2019 ◽  
Vol 49 (1) ◽  
pp. 26-33
Author(s):  
C. Y. Wu ◽  
Y. H. Chen ◽  
Y. K. Tang ◽  
E. J. Lin ◽  
Y. X. Lin ◽  
...  

Author(s):  
Muhammed Olawale Hakeem Amuda ◽  
W. Subair ◽  
O.W. Obitayo

The effect of some process parameters on the weight of zinc deposited on mild steel in a typical electroplating process is reported. The study indicates that the weight of zinc deposited on mild steel during the process is affected by plating temperature, current density, plating bath pH and plating time. The study established that optimum deposition of zinc is achieved at plating temperature of 320C, plating bath pH of 4.4, current density 40mA/cm2 and plating time of 30 minutes. 8.7mg of zinc was deposited at optimum deposition conditions. The profile of the zinc deposited decreases after optimum deposition is attained.


Author(s):  
N. I. Urbanovich ◽  
K. E. Baranovsky ◽  
E. V. Rozenberg ◽  
T. I. Bendik ◽  
A. A. Karpenkin ◽  
...  

A comparative analysis of the corrosion properties of zinc-containing coatings obtained on the basis of metallic powder zinc and dispersed hot-dip galvanized waste has been carried out. The results of a study of the corrosion resistance of zinc-containing coatings by the electrochemical method and in a salt spray chamber have shown that coatings obtained on the basis of dispersed hot-dip galvanized waste are not inferior in protective properties to coatings based on powder standard zinc.


2002 ◽  
Vol 100 (5) ◽  
pp. 33-36 ◽  
Author(s):  
John Hadley ◽  
Wim Verberne ◽  
Linda Wing ◽  
Jim O'Grady

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Mbouillé Cissé ◽  
Mohamed Abouchane ◽  
Tayeb Anik ◽  
Karima Himm ◽  
Rida Allah Belakhmima ◽  
...  

Electroless Ni-Cu-P alloy coatings were deposited on the ordinary steel substrate in an acidic hypophosphite-type plating bath. These coatings were characterized by a scanning electron microscope (SEM) and an X-ray diffraction. The micrograph shows that coating presents a nodular aspect and is relatively homogeneous and very smooth. The EDX analysis shows that the coating contains 12 wt.% of phosphorus element with a predominance of nickel element. In addition, the anticorrosion properties of the Ni-Cu-P coatings in 1 M HCl, 1 M H2SO4, and 3% NaCl solutions were investigated using Tafel polarization curves, electrochemical impedance spectroscopy, and SEM/EDX analysis. The result showed a marginal improvement in corrosion resistance in 3% NaCl solution compared to acidic medium. It also showed that the corrosion mechanism depends on the nature of the solution.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Paweł Lochyński ◽  
S. Charazińska ◽  
E. Łyczkowska-Widłak ◽  
A. Sikora ◽  
M. Karczewski

Long-term exploitation of industrial electropolishing baths may contribute to the emergence of surface defects and may limit the range of applicable current densities. Due to this, extending the time of use of industrial baths is a major challenge. The application of electrochemical reduction in the process of reduction industrial baths enabled to reduce its contamination and, as a result, to enhance the surface quality of electropolished samples of grade 304 stainless steel. The contamination influence of the electropolishing bath on such parameters of the electropolished samples as roughness, gloss, mass reduction, and corrosion resistance was compared. The conducted tests included reduction of the contaminated industrial bath with use of cathodic reduction and monitoring of bath contamination with use of emission spectrometry ICP-OES. Potentiodynamic tests in 0.5 M chlorine environment with the aim to determine the influence of electrochemical reduction of the plating bath on surface resistance demonstrated that the pitting corrosion resistance of samples electropolished in a bath after reduction was reduced by approximately 0.1 V in comparison with samples electropolished before reduction. The calculations conducted for 24 corrosion resistance measurements demonstrated that differences between the results were significant. Bath reduction leads to improved roughness and gloss, even by approximately 500 GU (gloss units). At the same time, mass reduction decreases even by 13% in comparison with the process conducted in the bath before reduction. This may have a positive influence by slowing down the bath contamination process and, as a result, it reduces negative environmental impact. Another argument that supports the reduction of industrial baths is slowing down the process of cathode contamination during the electropolishing process. In industrial conditions, this may extend the possibility to conduct the process without the need for cathode reduction or replacement.


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