Author

Russell Vick

Date of Award

5-2018

Degree Type

Honors College Thesis

Department

Polymers and High Performance Materials

First Advisor

James Rawlins, Ph.D

Advisor Department

Polymers and High Performance Materials

Abstract

While it is well known that polymeric coatings are used to protect metals from corrosion, efficient and reliable protocols for quantifying and estimating protective coatings’ lifetimes have yet to match real-time results in rate or in detected mechanisms of material failure. Alkoxysilane pretreatments are widely utilized for substrate preparation and improved coating system performance by changing the metal substrate surface morphology to improve adhesion at the coating-substrate interface by creating a foundation and excluding water from the system. Three pretreatments used were 3-aminopropyltriethoxy silane (APS), tetraethylortho silicate (TEOS), N-[3-(trimethoxysilyl)propyl]ethylenediamine (DAS). They were investigated to improve the understanding of the relationships between the silane solution and the physical and chemical structure of the resulting pretreatment layer. They were also investigated to correlate the pretreatment structure with the charge transfer resistance at the interface to quantify and understand the contribution charge transfer resistance has on the silane pretreatment’s anti-corrosive performance. It was determined using Infrared Spectroscopy that the most uniform silane network was generated when the silane to water molar ratio was low. The pretreatment results were validated with pull-off adhesion results using Mechanical Testing System (MTS). Further, the charge transfer resistance and instantaneous rate of corrosion of silane pretreated substrates is heavily dependent on the thickness and structure of the silane, as shown using Electrochemical Impedance Spectroscopy (EIS) and Electrochemical Frequency Modulation (EFM).

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