Corrosion Behaviors of Coated Aluminum Alloys in Simulated Corrosive Environment
type: CreativeWork
description: This study investigated the corrosion of an aluminum alloy with and without coatings under simulated corrosive environments. Coatings were selected and applied from commercial materials and techniques, consisting of microceramic, epoxy primer, and topcoat. The experiments for coated specimens were carried out under various corrosive conditions, specifically, hydrodynamic flow, immersion in salt water and DI water, varying temperatures, and simulated sun light. The hydrodynamic conditions were simulated using a rotating cylinder electrode (RCE) with rotational speeds of 200, 400, 600, 800, and 1000 rpm. The immersion in saltwater and sunlight illumination tests were applied for 8 hours, and the simulated exterior temperature variation were cycled for 7 days. Polarization techniques were used to study the corrosion mechanism and calculate the corrosion rate of coated specimens under simulated salt water. Microstructure of coated specimens were identified by using atomic force microscopy (AFM) and optical microscope (OM) analysis. Results indicated that corrosions in the simulated salt water were generally more serious than those in the distilled water. This was especially true for bare aluminum alloys, that its corrosion rates in the salt water exhibited two orders of magnitude higher than those in the DI water. The combination of an environmentally friendly electrodeposited ceramic coating with a primer and topcoat, which results in a chromium-free coating, exhibited a higher polarization resistance and a lower corrosion rate than the traditional chromate conversion coating combination. In addition, for all coated Al alloys, the corrosion rate increased with increasing rotation speed. For immersion portion, immersion in salt water accelerated the pitting corrosion process and increased the corrosion rate of the aluminum alloy five times higher as compared to the samples without immersion. For the varying temperature portion, the rates of corrosion nearly doubled for …
abstract: This study investigated the corrosion of an aluminum alloy with and without coatings under simulated corrosive environments. Coatings were selected and applied from commercial materials and techniques, consisting of microceramic, epoxy primer, and topcoat. The experiments for coated specimens were carried out under various corrosive conditions, specifically, hydrodynamic flow, immersion in salt water and DI water, varying temperatures, and simulated sun light. The hydrodynamic conditions were simulated using a rotating cylinder electrode (RCE) with rotational speeds of 200, 400, 600, 800, and 1000 rpm. The immersion in saltwater and sunlight illumination tests were applied for 8 hours, and the simulated exterior temperature variation were cycled for 7 days. Polarization techniques were used to study the corrosion mechanism and calculate the corrosion rate of coated specimens under simulated salt water. Microstructure of coated specimens were identified by using atomic force microscopy (AFM) and optical microscope (OM) analysis. Results indicated that corrosions in the simulated salt water were generally more serious than those in the distilled water. This was especially true for bare aluminum alloys, that its corrosion rates in the salt water exhibited two orders of magnitude higher than those in the DI water. The combination of an environmentally friendly electrodeposited ceramic coating with a primer and topcoat, which results in a chromium-free coating, exhibited a higher polarization resistance and a lower corrosion rate than the traditional chromate conversion coating combination. In addition, for all coated Al alloys, the corrosion rate increased with increasing rotation speed. For immersion portion, immersion in salt water accelerated the pitting corrosion process and increased the corrosion rate of the aluminum alloy five times higher as compared to the samples without immersion. For the varying temperature portion, the rates of corrosion nearly doubled for …
author: Yue, Jingyi
keywords: Corrosion; Aluminum alloy; Electrochemistry; Coatings; Inhibitors, Chemistry, Physical Chemistry
date published: 2015-05-01T07:00:00Z
date modified: 2026-07-24T06:08:52Z
provider: Western Kentucky University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Western Kentucky University