Masters Theses

Abstract

"The aim of the present work was to develop a spontaneous spray-based cerium oxide conversion coating process. The design and optimization of a spontaneous spray-based cerium oxide conversion coating process is reported in this thesis. Aluminum test panels were coated spontaneously by non-acidified, pre-and post-acidified solutions.

The salt fog performance of spray-deposited cerium oxide conversion coatings was optimized by varying the hydrogen peroxide concentration, pH and the order of mixing of the reagents. Hydrogen peroxide concentration was varied in the range of 2.5 ml, 5 ml and 10 ml in a total solution volume of ~250 ml, which resulted in a decrease in solution pH to ~2.3. Higher hydrogen peroxide concentrations resulted in faster precipitation/deposition rates. In acidified solutions, pH was adjusted to ~2.2 prior to hydrogen peroxide addition. Characterization of the coatings was performed by SEM, AES and XPS to analyze the coating morphology, thickness of the coating and oxidation state of cerium species. The corrosion resistance performance of the coatings was judged on the results of salt fog testing.

It was observed that hydrogen peroxide concentration affected both coating deposition and salt fog performance. Coating thickness was found to increase with hydrogen peroxide concentration and coating time. Coating thickness of the order of ~ l µm was obtained for the thickest coating. However, a balance between deposition rate and coating thickness was required to optimize performance. A passing rate of 73% was obtained for two-week salt fog testing when the spray process was optimized for the nonacidified solution containing 5 ml hydrogen peroxide for a coating time of 15 minutes"--Abstract, p. iii

Advisor(s)

William G. Fahrenholtz

Committee Member(s)

Matthew O'Keefe
Thomas J. O'Keefe

Department(s)

Materials Science and Engineering

Degree Name

M.S. in Ceramic Engineering

Sponsor(s)

U.S. Air Force Research Laboratory (Wright-Patterson Air Force Base, Ohio)

Publisher

University of Missouri--Rolla

Publication Date

Spring 2004

Pagination

ix, 65 pages

Note about bibliography

includes bibliographical references (pages 63-64)

Rights

© 2004 Vaidehi Chandrahasya Dongre, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Subject Headings

Aluminum alloysCerium oxidesCoating processesMetal spraying

Thesis Number

T 9124

Print OCLC #

173279307

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