Effect of Copper Concentration on the Localized Corrosion of Aluminum Alloy for Heat Exchanger Tube

다국어 초록 (Multilingual Abstract)

This study examined the alloying effect of Cu content on the localized corrosion properties of Al alloy in synthetic acid rain containing 200 ppm of Cl- ion. The results were obtained from electrochemical test, scanning electron microscopy (SEM), and time of flight secondary ion mass spectrometry (ToF-SIMS) mapping. Severe localized corrosion was occurred at the Al-0.03 wt.% Cu alloy. The negative effect of Cu on the pitting corrosion was attributed to the presence of the Al2Cu precipitates. The Cu-containing intermetallic compound can cause galvanic corrosion because it has more noble potential than Cu depleted region.

목차 (Table of Contents)

• ABSTRACT 6
• 1. INTRODUCTION 7
• 2. LITERATURE REVIEW 10
• 2.1. Aluminum Heat Exchanger Tube and Corrosion 10
• 2.1.1. Aluminum Heat Exchanger Tube 10
• 2.1.2. Corrosion Problem of Aluminum Heat Exchanger Tube 11
• 2.2. Basic Principles of Corrosion 16
• 2.2.1. Electrochemical Reactions of Aqueous Corrosion 16
• 2.2.2. Polarization 18
• 2.2.3. Passivity 23
• 2.2.4. Forms of Corrosion 25
• 2.3. Corrosion Test Method 30
• 2.3.1. Electrochemical Impedance Spectroscopy (EIS) 30
• 2.3.2. Potentiodynamic and Potentiostatic Polarization Test 32
• 3. EXPERIMENTAL 33
• 3.1. Specimen and Solution Preparation 33
• 3.2. Electrochemical Investigation Method 36
• 3.3. Surface Analysis 37
• 4. RESULTS and DISCUSSION 38
• 4.1. Potentiodynamic Polarization Test 38
• 4.2. Potentiostatic Polarization Test 41
• 4.3. Electrochemical Impedance Spectroscopy (EIS) 43
• 4.4. Surface Analysis 52
• 6. CONCLUSIONS 57
• 7. REFERENCES 58
• 논문요약 63