Honors Theses and Capstones

Date of Award

Spring 2017

Project Type

Senior Honors Thesis

College or School

CEPS

Department

Chemical Engineering

Program or Major

Chemical Engineering

Degree Name

Bachelor of Science

First Advisor

Dale Barkey

Abstract

Hard-anodized alumina coatings were formed in sulfuric acid at low temperature and high current density in the presence of carboxylic acid additives. Citric acid, trimesic acid, mellitic acid and ethylenediaminetetraacetic acid (EDTA) were utilized in varying concentrations. The additives were chosen for their capacity to form complexes with tri-valent aluminum and hence impart chemical stability to the coatings. The coatings were sealed in boiling water, and corrosion resistance was observed in a high pH solution of potassium hydroxide. The coatings were examined using scanning electron microscopy (SEM) to assess coating thickness and pore dimensions. Thicker coatings were produced when the additive inhibited oxide coating dissolution, increasing corrosion resistance. Overall, carboxylic acid additives showed a positive impact on corrosion resistance when coupled with sealants. More research in this field could improve products used in cleaning and cooking environments to withstand conditions of high and low pH.