Contents
xi
7.7 Application of Coatings.................................................................... 229
7.7.1 Application Methods ........................................................... 230
7.7.1.1 Brushing ................................................................ 231
7.7.1.2 Rolling .................................................................... 231
7.7.1.3 Roller Coating ....................................................... 231
7.7.1.4 Spray Painting ....................................................... 232
7.7.1.5 Powder Coating .................................................... 233
7.7.1.6 Electrodeposition of Polymers ............................234
7.7.2 Multilayer Coatings ............................................................. 235
7.7.3 Curing .................................................................................... 238
7.7.3.1 Air-Drying ............................................................. 239
7.7.3.2 Baking .................................................................... 239
7.7.3.3 Force Drying ......................................................... 240
7.7.3.4 Reflowing ............................................................... 240
7.7.3.5 Radiation Curing .................................................. 240
7.7.3.6 Vapor Curing......................................................... 240
7.7.4 Inspection .............................................................................. 240
7.8 Maintenance of the Coating ............................................................ 241
7.9 Selecting a Paint System ................................................................... 242
7.9.1 Area 1: Mild Exposure ........................................................ 247
7.9.2 Area 2: Temporary Protection, Normally Dry
Interiors ................................................................................. 248
7.9.3 Area 3: Normally Dry Exteriors ......................................... 248
7.9.4 Area 4: Freshwater Exposure ............................................. 250
7.9.5 Area 5: Saltwater Exposure ................................................ 251
7.9.6 Area 6: Freshwater Immersion ........................................... 251
7.9.7 Area 7: Saltwater Immersion .............................................. 251
7.9.8 Area 8: Acidic Chemical Exposure (pH 2.0–5.0) .............. 251
7.9.9 Area 9: Neutral Chemical Exposure (pH 5.0–10.0) .......... 252
7.9.10 Area 10: Exposure to Mild Solvents .................................. 252
7.9.11 Area 11: Extreme pH Exposure .......................................... 252
8 Corrosion of Metallic Coatings ............................................................... 255
8.1 Corrosion Cell .................................................................................... 255
8.2 EMF Control Protection by Noble Metals ..................................... 264
8.2.1 Mechanism of Control Protection ..................................... 264
8.2.1.1 Copper Coatings ................................................... 264
8.2.1.2 Gold Coatings ....................................................... 266
8.3 Anodic Control Protection by Noble Metals ................................. 267
8.3.1 Mechanisms of Control Protection.................................... 267
8.3.1.1 Nickel Coatings .................................................... 267
8.3.1.2 Chromium Coatings ............................................ 271
8.3.1.3 Tin Coatings (Tinplate) ........................................ 273
8.3.1.4 Lead Coatings ....................................................... 276
8.4 Cathodic Control by Sacrificial Metal Coatings ........................... 277