Protective coatings are often used with cathodic protection to protect steel structures in buried or submerged services. Cathodic disbondment resistance is always on the top of the coating property list required by end users. Many standard test methods for cathodic disbondment are available to evaluate the resistance to cathodic disbondment. However, there is no universal agreement on which standard to run the test. Test parameters like voltage, electrolyte composition, test temperature, test time, sample configuration etc. vary over a wide range among various test standards. Not all test parameters have been specified in the test standards and frequently, the standard test methods are modified by users. It is difficulty to rank coatings based on the test results obtained from different labs. NACE has formed a Technical Group, TG #470 to develop a new standard to include all test parameters on the cathodic disbondment test. A review paper on “critical evaluation of international cathodic test methods” was published in 2008 to assess many test parameters. Here we highlight special enhancements: (1) to use the high temperature and environmental friendly reference electrode - Ag/AgCl; (2) to define the test temperature measurement procedure; (3) to check the accuracy of the reference electrode; (4) to develop an inexpensive anode isolation method to eliminate the hypochlorite formation, etc.
Key words: protective coatings, cathodic delamination, test parameters, cathodic disbonding, test parameters, hypochlorite, anode isolation