College

College of Engineering and Polymer Science

Date of Last Revision

2021-04-25 18:47:05

Major

Corrosion Engineering

Honors Course

Honors Project (4250:497)

Number of Credits

3

Degree Name

Bachelor of Science

Date of Expected Graduation

Spring 2021

Abstract

The corrosion performance of sol-gel coated AISI 1008 carbon steel was investigated in 3.5 wt% NaCl solutions of pH 7, 9, and 12 using electrochemical measurements. A corrosion inhibitor, benzotriazole (BTA) was added to the sol-gel mixture and tested as a second, modified sol-gel coating. Sol-gel films adhered evenly to metal samples and were characterized by FTIR spectroscopy. Electrochemical Impedance Spectroscopy (EIS) showed an increase in polarization resistance from blank to sol-gel coated samples (600-18,800,000 ohms). Cyclic polarization (CPP) curves showed positive hysteresis loops for blank and unmodified sol-gel coated samples which increased at high pH following the backward potential scan, suggesting destruction to the passive film and pitting corrosion. The hysteresis loops after the addition of BTA followed an opposite trend. CPP also confirmed a lower corrosion current density and more positive corrosion potential for sol-gel films (avg: 0.0019 μA/cm2 and 94.7 mV/SCE for BTA modified sol-gel film) vs. blank samples (avg: 94.7 μA/cm2 and -540 mV/SCE). While unmodified sol-gel films slightly increased corrosion protection of AISI 1008 carbon steel, BTA modified sol-gel coated carbon steel exhibited the highest protection by far, obtaining an average corrosion rate of 0.000022 mm/yr, nearly three orders of magnitude lower than blank samples.

Research Sponsor

Dr. Bastidas

First Reader

Dr. Cong

Second Reader

Dr. Newby

Honors Faculty Advisor

Dr. Evans

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