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Full-Text Articles in Engineering
Corrosion Protection Of Steel Using Nonanomalous Ni-Zn-P Coatings, Basker Veeraraghavan, Bala Haran, Swaminatha P. Kumaraguru, Branko N. Popov
Corrosion Protection Of Steel Using Nonanomalous Ni-Zn-P Coatings, Basker Veeraraghavan, Bala Haran, Swaminatha P. Kumaraguru, Branko N. Popov
Faculty Publications
A novel technique for obtaining nonanomalous Ni-Zn-P coatings with high Ni content (74 wt % as compared to 15-20 wt % in the conventional plating method) has been developed. These coatings show promise as a replacement for Cd in sacrificially protecting steel. Ni-Zn-P coatings were deposited using an electroless method from a solution containing NiSO4, complexing agent and ammonium chloride. Varying the concentration of ZnSO4 in the bath controls the final amount of Zn in the deposit. The Zn content in the coating was optimized based on the corrosion resistance of the final deposit. Coatings with 16.2 …
The Role Of Thallium As A Hydrogen Entry Promoter On Cathodically Polarized Hy-130 Steel, G. Zheng, Branko N. Popov, Ralph E. White
The Role Of Thallium As A Hydrogen Entry Promoter On Cathodically Polarized Hy-130 Steel, G. Zheng, Branko N. Popov, Ralph E. White
Faculty Publications
Hydrogen permeation experiments were carried out to investigate the effect of thallium on hydrogen entry into HY-130steel. These experiments show that the presence of thallium ions in an electrolyte drastically increase the hydrogen entry rate. The hydrogen entry efficiency and hydrogen surface coverage were increased by a factor of 10 and 6, respectively. In order to fit the permeation experimental data, the Iyer-Pickering-Zamanzadeh (I-P-Z) hydrogen permeation model was modified by including a mass-transfer term in the discharging equation. The relationship between hydrogen permeation and the hydrogen evolution reaction were investigated and new relationships were obtained.
Surface Treatment For Mitigation Of Hydrogen Absorption And Penetration Into Aisi 4340 Steel, G. Zheng, Branko N. Popov, Ralph E. White
Surface Treatment For Mitigation Of Hydrogen Absorption And Penetration Into Aisi 4340 Steel, G. Zheng, Branko N. Popov, Ralph E. White
Faculty Publications
The effectiveness of underpotential deposition of Pb onto a membrane made of AISI 4340 steel on the reduction of the hydrogen evolution reaction on the membrane and the degree of hydrogen ingress into the membrane was determined. In the presence of a monolayer coverage of Pb on the membrane surface, the hydrogen evolution currents were reduced by a factor of two compared with the values obtained on bare steel, and the steady-state hydrogen permeation flux through the steel membranes was reduced by 71%.
Mathematical Modeling Of Cathodic Protection Using The Boundary Element Method With A Nonlinear Polarization Curve, J. F. Fan, S. N. R Pakalapati, T. V. Nguyen, Ralph E. White, R. B. Griffin
Mathematical Modeling Of Cathodic Protection Using The Boundary Element Method With A Nonlinear Polarization Curve, J. F. Fan, S. N. R Pakalapati, T. V. Nguyen, Ralph E. White, R. B. Griffin
Faculty Publications
The distributions of potential and current density around a cathodically protected pipeline in seawater were determined using the boundary element technique. A nonlinear polarization curve for a low carbon steel in artificial sea water was obtained from dc-potentiodynamic measurements and was fitted for use as the boundary condition on the pipe. The program was used to evaluate cases in which one or two aluminum sacrificial anodes are used to protect a low carbon steelpipe in seawater. The results show that the number of anodes, the sizes of the anodes, and the distance between the anodes and the cathode are of …
Comparing Electrochemical Impedance Spectroscopy Methods For Estimating The Degree Of Delamination Of Organic Coatings On Steel, S. A. Mccluney, S. N. Popova, Branko N. Popov, Ralph E. White, R. B. Griffin
Comparing Electrochemical Impedance Spectroscopy Methods For Estimating The Degree Of Delamination Of Organic Coatings On Steel, S. A. Mccluney, S. N. Popova, Branko N. Popov, Ralph E. White, R. B. Griffin
Faculty Publications
Electrochemical impedance spectroscopy (EIS) was used to evaluate the degree of delamination of the epoxy primer Uniprime ED-41 electrocoated on phosphate-treated cold-rolled steel in 3.5% NaCl exposed to air. Specimens with coating thicknesses of 20.3 and 20.8 µm and surface areas of 78.5 cm2 were used. Coating parameters were obtained using a circuit-analog model. The area of delamination was estimated using several EIS parameters, including the pore resistance and the break point frequency. These values were compared to the corroded area determined visually. All methods considered exhibited a strong correlation over some or all of the range of …