Abstract
A protective coating is applied to resist chemical attacks including corrosion to a substrate. Two basic aspects, chemical inertness and permeation resistance, of the coating are therefore important. ECTFE has been successfully used as a coating to protect metal substrates in corrosive environment for years. ECTFE develops an ultimate adhesion strength on metal substrates greater than its break strength, when it is applied properly. Without primer, ECTFE coating still develops similar adhesion strength at a slower rate. The bulkier chlorine atom provides a higher barrier energy for segmental movement and, therefore, gives a molecule with higher rigidity. This increased rigidity gives ECTFE an increased heat distortion temperature, a reduced thermal expansion coefficient, and an improved resistance to chemical permeation. The superior surface smoothness of ECTFE coating further enhances its chemical resistance by not allowing exhaust fumes to anchor mechanically on the coating surface. In addition, the ECTFE coating has greater flame resistance than competitive coatings. ECTFE coating can be applied as thick as 120 mils when a correct fabrication process is used. The increased thickness certainly further improves the resistance of chemical permeation.
