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A computer code for detecting deterioration of organic coatings through impedance measurements
Author(s) -
Rocchini G.
Publication year - 1999
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/(sici)1521-4176(199909)50:9<527::aid-maco527>3.0.co;2-h
Subject(s) - electrical impedance , code (set theory) , computer science , materials science , electrical engineering , engineering , programming language , set (abstract data type)
Some basic considerations about organic coatings are given and a simple electric network simulating the response of the metal‐coating system, exposed to an aggressive environment, to a sinusoidal signal of high frequency is examined. It is also proved that this approach provides reliable and correct information on the coating performance when the film defects have a negligible area. The computer program, developed to perform measurements over the [6 × 10 3 , 6 × 10 4 ] Hz frequency interval and process experimental data with a prefixed model, is briefly discussed as concerns its main features which are the proper choice of the voltage amplitude to be applied to the system under investigation and the optimisation of the current range as a function of the operating frequency. Two interesting experimental applications are illustrated: the first one refers to carbon steel specimens painted with different commercial products and exposed in a salt‐spray cabinet. The second application is dealing with an epoxy coating applied to aluminium brass specimens that were exposed to artificial sea‐water at 40°C and having different flow rates. In both cases results were very promising and demonstrated the usefulness and validity of this methodology which is an effective way to face the problem to monitor the resistance to corrosion of composite systems.