Marine Corrosion and Protection Lecturer Dr SanDer Chyou

Marine Corrosion and Protection • Lecturer: Dr. San-Der Chyou (邱善得老師) • Class Hours: Wednesday 9: 20 -12: 10 • Room : 國立台灣海洋大學機械系教室 • Textbook: 1. Principles and Prevention of Corrosion –by Denny A Jones 2 nd edition 1996, ISBN 0 -13359993 -0

Scoring (計分方式) p Mid term examin. 期中考： 30% p Final term examin. 期末考： 40% p 平時： 30% home works 作業(資料查閱研讀) (20%) attendance 出席率 (10%) 03/10/15 ME 7049 4

Chapter 1 Introduction

Powerboat Zincs Trim Tab 6 Zincs MElec-Ch 5 - 15

Between Boats • Two different metals § Aluminum vs steel (or other metal) § Immersed in current-carrying solution • Sea water § Interconnected by current-carrying conductor • AC ground (green) wire MElec-Ch 5 - 16

Indirect Cathodic Protection • Used when direct contact not possible § Zinc bolted to outside of hull § Inside boat connect with insulated AWG#8 to • Rudder Post • Shaft (requires shaft brush) MElec-Ch 5 - 17

Results of Stray Current Corrosion MElec-Ch 5 - 18

Offshore Wind Turbines Ø Offshore wind turbines often operate under harsh conditions that require solid technology and robust operations. Corrosion problem is an critical issue on the engineering design for constructing structure of offshore wind turbines.

冷卻水系統腐蝕監測 綜合研究所 TPRI 21 Taiwan Power Company TPC

海洋牧場把廢水作為藻類養殖營養源 800 MW with 1% CO 2 captured = 3. 5 ton/hr Dry microalage 8 MW with 100% CO 2 captured = 3. 5 ton/hr Dry microalage CO 2 Waste water Nutrients (N, P. . ) OUTPUTS Liquid fuels Chemicals Algal biomass Proteins INPUTS ‘Polished’ water Light O 2 25 氫能材料

Degradation & Failure Mechanism of Organic Coating Fe. O. H 2 O Fe. O. Fe 2 O 3. 4 H 2 O Fe(OH)2. 2 Fe(OH)3 Fe 2(OH)6 Fe 2 O 3. 3 H 2 O Passive Films vs. Oxides

How corrosion occurs in the marine environments 4. 1 The reaction of a metal with electrolyte 4. 2 The electrochemical nature of corrosion 4. 2. 1 the reaction of a metal with its environment 4. 2. 2 the mixed potential theory 4. 2. 3 polarization and corrosion rate 4. 2. 4 passivation and its breakdown 4. 3 The characteristics of marine environments 4. 3. 1 corrosivity of seawater 4. 3. 2 corrosivity of marine atmospheres 4. 4 Factors affecting marine corrosion 4. 4. 1 salinity and chlorinity 4. 4. 2 temperature, dissolved gases, velocity, p. H, pollutants, biological organisms 4. 4. 3 relative humidity, airborne contaminants etc.

Common forms of marine corrosion 4. 5. 1 uniform corrosion 4. 5. 2 galvanic corrosion 4. 5. 3 dealloying 4. 5. 4 crevice corrosion 4. 5. 5 pitting corrosion 4. 5. 6 intergranular corrosion and weld decay 4. 5. 7 exfoliation 4. 5. 8 stress corrosion cracking 4. 5. 9 hydrogen related damages 4. 5. 10 erosion corrosion and cavitation damage 4. 5. 11 microbiologically influenced corrosion (MIC) 4. 5. 12 stray current corrosion 4. 5. 13 biofouling

How to control and prevent corrosion 5. 1 Materials selection for corrosion prevention 5. 2 Design against corrosion 5. 3 Theory and practice of cathodic protection 5. 4 Theory and practice of corrosion inhibitors 5. 5 Theory and practice of metallic coatings 5. 5. 1 thermal spray, metallization 5. 5. 2 hot-dip galvazing 5. 5. 3 conversion coatings (anodizing, chromating and phosphating) 5. 5. 4 electroplating, electroless plating, immersion plating. 5. 6 Theory and practice of organic coatings 5. 6. 1 composition and characteristics of paints 5. 6. 2 types of paints 5. 6. 3 protective coatings for marine applications 5. 6. 4 paint failures 5. 6. 5 environment-friendly anti-fouling paints ("green" coatings) 5. 6. 6 coatings and cathodic protection for marine structures 5. 7 Theory and practice of plastic coatings 5. 8 Theory and practice of concrete coatings