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AGENCY USE ONLY (Leave blank)2. REPORT DATE
December 2003
REPORT TYPE AND DATES COVERED
FUNDING NUMBERSMOOOl 4-03-1-00286. AUTHOR(S) Branko N. Popov
PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)Department of Chemical Engineering Swearingen Engineering Center University of South Carolina Columbia, SC 29208
SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)Office of Naval Research, 800 N. Quincy St., Arlington, VA 22217-5000
PERFORMING ORGANIZATION REPORT SUMBER
SPONSORING/ MONITORING AGENCY REPORT NUMBER
SUPPLEMENTARY NOTESThe views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of Army position, policy or decision, unless so designated by other documentation.
12a. DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution is unlimited.
12b. DISTRIBUTION CODE
ABSTRACTThe objective of this investigation was to develop novel processes for depositing ternary Zn-Ni-X (X=Cu or P) alloys for replacement of Cd coatings in sacrificial protection of steel substrates. Introducing small amounts of Cu in the Zn-Ni plating bath results in alloys with reduced amount of Zn in the final deposit. This alloy shows improved corrosion performance that is 4 times higher than that of Cd coatings. Also, the use of autocatalytic method was investigated to deposit amorphous Ni-Zn-P alloys. The electroless Ni-Zn-P alloy shows improved corrosion performance that is 5 times higher than that of Cd coatings and reduces the hydrogen ingress into steel to 94%. A novel electrolytic process was developed to deposit Ni-Zn alloys with high Ni content. Deposition parameters like pH and temperature were optimized based on composition and the surface morphology of the coating. The Zn content in the coating was optimized based on the corrosion resistance of the final deposit. Finally, corrosion studies shows that Ni-Zn coatings obtained using these methods show a 5 times increase in barrier resistance as compared to Cd coatings. Also a mathematical model was developed to study the electroless Ni-Zn-P deposition. 14. SUBJECT TERMS Steel, Zn-Ni alloys, Sacrificial Protection, Corrosion resistance. Hydrogen Embrittlement, electroless process, model.
SECURITY CLASSIFICATION OF REPORT
Swaminatha P Kumaraguru, Basker Veeraraghavan and Branko N. Popov , "NonAanomalou...