Icp. Margarit et al., About coatings and cathodic protection: Electrochemical features of coatings used on pipelines, J COAT TECH, 73(914), 2001, pp. 61
Tie behavior of a cool tar, a polyethylene, and a fusion bonded epoxy was e
valuated. Coated samples with and without intentional failures exposing the
metallic substrate were submitted to different levels of cathodic polariza
tion. The process of delamination was monitored with current and impedance
measurements. The delamination was quantified by a standard method. No quan
titative relationship between the delaminated areas and electrochemical par
ameters could be found; the reasons are discussed in terms of the propertie
s of the coatings. It was shown that the higher the dielectric strength of
coatings, the more critical the role of pores and mechanical damage in dete
rmining cathodic protection effectiveness.