Consistent coating adhesion is impaired by microcontaminants present in metal surfaces during fabrication as well as those potentially embedded during surface preparation blast processes occurring in field maintenance. The purpose of the paper is to demonstrate the importance of chemical adhesion provided in conjunction with different surface preparation technologies such as WAB (wet abrasive blasting) with chemical aditive, dry abrasive blasting with a post rinse of chemical additive, or UHP (ultra-high pressure) water blasting with chemical additive.
A chemical additive application process decontaminates surfaces at the molecular level, eliminating visually undetectable levels of highly corrosive substances, changes the surface morphology creating a uniform receptive surface of an amorphous oxide film to improve coating performance exponentially.
Historically the focus has been on the adverse anions (chlorides, sulfates nitrates) with little attention Aggregated FeS and ionically bonded FeCl2 is a pervasive, difficult, and high-liability issue for pipeline, petrochemical, power, shipping, and other industries. Situational variations (meteorological, geographical, seasonal, etc.) can confound conventionally specified surface preparation attempts to achieve perfect or near-perfect metal cleanliness, thus reducing expected coating life by 30 to 75 percent. Because conventional surface preparation processes have historically been unable to adequately relieve microcontamination of metal surfaces, organizations have settled for an uneasy balance between economic and physical feasibilities that exclude the possibility of achieving ideal surface preparation outcomes and rely more heavily upon barrier coatings to supply needed corrosion control.
However, coatings cannot fill the gap; no matter how advance the coating, surface-tolerance does not extend to application over iron chloride (FeCl2) or iron sulfide (FeS) contaminated steel, as coating performance is highly dependent upon unimpeded bonding with the surface it is meant to protect. addressing the high aggregation of FeS (iron sulfide) on a substrate of today's metal assets.
This chemical additive application process reacts and solubilizes FeS (iron sulfide) with an oxidation process to reduce the microbial preference areas and solubilizes the ionically bonded FeCl2 (iron chloride) aggregated on the metal substrate, in addition reacts and solubilizes FeCl2 (iron chloride), SO2-(sulfate) and NO-3 (nitrate) over the general surface area to be decontaminated.
The chemical additive addresses the cations and insoluble sulfides and chemically breaks the ionic attraction between the anions and cations and as a result eliminates the cathode-anode reaction (corrosion reaction).
