Page 308 - Challenges in Corrosion Costs Causes Consequences and Control(2015)

286 CORROSION CONTROL AND PREVENTION

Coatings such as modified epoxies, coal-tar epoxy, or solvent-borne epoxy have
been used by many shipbuilders since 1998. The problem with these coatings is that
the lifetime of these coatings is such that they can give protection for only 8–10 years,
which is less than the design life of the vessels. These coatings are not resistant to the
temperatures in double-hulled tankers and the bacteria that causes pitting corrosion
on the bottom of tanks. The use of solvent-free epoxy on the top and bottom of a
crude tanker should prevent corrosion of the tanker.

4.23 CORROSION CONTROL IN AIRCRAFT

Typical causes and sources of corrosion are as given below. Corrosion can occur dur-
ing manufacture as well as in operation.

Manufacture of Aircraft
Basic Design Manufacture and Processing

Poor design Materials finishing processes
Crevices Bonding process
Stress Training
Dissimilar metals Assembly
Finish system
Materials selection

Operator

Maintenance Problem Areas Finish Deterioration Operational Environment
Neglect Chipping Sea coast
Improper repairs Scratches Tropical
Poor corrosion control Breaks around fasteners Humidity
Program or lack of Abrasion Industrial
implementation
Poor training Deposits
Age

Accidental Contamination Environment in Airplanes

Lavatory spillage Condensation
Galley spillage Animals
Chemical spills Fish
Mercury Mercury
Fire residues Microbial growth