Porosity of Electrodeposited Coatings: Its Cause, Nature, Effect and Management

219 1. Classification 219 2. The Physical Attributes of Pores 221 3. Factors Influencing Porosity in Electrodeposited Coatings 223 3.1 The Effect of Surface Preparation 223 3.2 The Effect of an Undercoat 225 3.3 The Effect of Coating Thickness 227 3.4 Plating Bath Effects 230 3.5 The Effect of Porosity on a Coatings Performance ... 234 4. Methods for Detecting Porosity 237 5. Pore Detection Tests 238 5.1 Chemical Pore Detection Tests 238 5.2 Ferricyanide Type Tests 239 5.3 Hot Water Test 239 5.4 Gaseous Pore Detection Reagents 242 5.5 Other Chemical Pore Detection Tests .·, 243 5.6 Electrochemical Pore Detection Methods 245 5.7 Anodic Methods of Pore Detection 245 5.8 Cathodic Methods of Pore Detection 248 6. Physical Methods for Studying Porosity 248 6.1 Studies of Porosity Using Microscopy 249 6.2 Other Physical Methods for Studying Porosity 250