Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Wipf, David O.

Committee Member

Pittman Jr., Charles U.

Committee Member

Xia, Kang

Committee Member

Gwaltney, Steven

Committee Member

Henry, William P.

Date of Degree

5-1-2010

Document Type

Dissertation - Open Access

Major

Chemistry

Degree Name

Doctor of Philosophy

College

College of Arts and Sciences

Department

Department of Chemistry

Abstract

Organic coatings are extensively used as protective coatings in several industries including the automotive and aircraft industries. The last few years have witnessed an increased interest in improving not only the mechanical properties but also the corrosion protection properties of organic coatings. Among the currently investigated methods of improving the performance of organic coatings is the incorporation of additives in the organic paint matrix. Vapor grown carbon nanofibers (VGCNFs) are a class of carbon fibers that are produced by catalytic dehydrogenation of a hydrocarbon at high temperatures. Depending on the method of synthesis and the post-treatment processes, the diameter of the VGCNFs is normally in the 10-300 nm range. The small size, light weight, high aspect ratio, and unique physical, thermal, mechanical, and electrical properties of VGCNF make it an ideal reinforcing filler in polymer matrix nanocomposites to enhance the mechanical properties of the pure polymeric material in high performance applications in several industries such as the automotive, aircraft, battery, sensors, catalysis, electronics, and sports industries. The main objective of the current investigation was to study the corrosion protection offered by the incorporation of VGCNFs into a commercial alkyd paint matrix applied to the surface of mild steel coupons. The corrosion protection was investigated by immersing samples in air saturated 3% NaCl solution (artificial seawater). The samples were studied by electrochemical impedance spectroscopy (EIS) along with other measurements, including electrochemical (open circuit potential, cyclic voltammetry), chemical (salt spray test), electrical conductivity, and surface analysis (SEM, AFM, optical profilometry, and nanoindentation). The study involved the investigation of the effect of the weight percent (wt %) of the VGCNF as well as the coating film thickness on the corrosion protection performance of the coated steel samples when exposed to the corrosive electrolyte. By way of contrast, the EIS behavior of steel coupons coated with a paint coating incorporating different weight percents of powdered silicon carbide (SiC) particles was also studied. The EIS spectra were used to calculated and graph several corrosion parameters for the investigated systems. At the end, the studied coatings were ranked in order of their anticorrosive properties.

URI

https://hdl.handle.net/11668/17064

Comments

accelerated corrosion testing||corrosion protection||corrosion||open circuit potential (OCP)||conductive polymers (CPs)||silicon carbide (SiC) particles||vapor grown carbon nanofibers (VGCNFs)||organic coatings||alkyd paints||mild steel||Electrochemical impedance spectroscopy (EIS)||salt spray test

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