Westhill, Aberdeenshire May 7, 2018 (Issuewire.com) - RADICAL IMPROVEMENT - A new technology comprises a new approach to metal surface preparation: stop flash rust and provide comprehensive, elevated surface hygiene through removal of ionic contaminants (even under oxide and sulfide films) to prevent mechanisms that tend to trigger undercoating corrosion. This radical new approach was recently upgraded and launched. Details were presented recently at NACE Northern Area Western Conference (March 2018) and will also be presented during the NACE CORROSION 2018 conference in June 2018
PARADIGM SHIFT IN SURFACE PREPARATION
Corrosion control, in general, acknowledges the importance of surface preparation in coating control methods involving coatings which, while widely employed, garner mixed results in achieving consistent protection because surface preparation determines coating and lining performance in corrosion control.
The universal Achilles’ heel among coatings and linings systems is that they rely on bond strength and continuity, which in turn, relies on surface hygiene to eradicate microcontaminants ubiquitous in metal surfaces that catalyze and extend undercoating corrosion reactions. It logically follows that to optimize coating performance one must ensure maximum hygiene at the coating/substrate adhesion interface.
DIFFICULT TASK
Even in controlled environments, shops and bays, metal contaminant removal is a difficult task. Situational variations causing rapid flash rust (meteorological, geographical, seasonal, etc.), site configurations, and other realities only confound conventionally-specified surface preparation attempts to achieve perfect or near-perfect metal hygiene.
Protective coating effectiveness can be literally undermined by corrosion. The purpose of surface preparation must, therefore, be to (a) ensure coatings have consistent, uninterrupted contact with substrate metal to reach their maximum potential for adhesion and (b) prevent corrosion reactions from occurring beneath cured coatings. Moreover, ineffective surface preparation processes (a) cannot achieve the above (b) drive up costs through rework and (c) may be unsuitable for the work site, service environment, or limited for use with certain coatings.
BACKGROUND
Ferrous sulfides, present in both newly fabricated and in-service metal, attract and bond with hygroscopic contaminants (e.g.: salts, nitrates) are known to impede coating bond strength and cause corrosion reactions to occur and expand beneath coatings, rendering them effectively insoluble and virtually undetectable beneath naturally occurring oxide layers. Soluble salts contain chloride, nitrate, and sulfate as adverse anions. Although most of the salts are soluble in water, they cannot be easily removed from steel surface by washing or abrasive blasting. Salts may also exist in pits and crevices on corroded surfaces within or under the rust.
Sulfide compounds tendency to aggregate in metal surfaces during fabrication makes them ubiquitous in steel. Sulfide compounds render steel vulnerable to corrosion-triggering ionic attraction, even when sulfur is present at very low ppm. When soluble salts bond with the adverse anions, they behave as functionally insoluble contaminants. Moreover, it is difficult to even detect such hidden salts as sulfides tend to penetrate into the intergranular crevices in the metal substrate.
These ionic corrodants are hygroscopic, drawing in moisture and initiating a corrosion chain reaction that continues unimpeded, and expands corrosion reactions under coating film. Coatings in such situations are vulnerable in two ways. First, the coatings impeded from establishing a strong bond with the substrate due to the interference of the contaminants. Second, the applied coatings are at continually at risk from disbandment caused by pressure from corrosion tubercles that develop at the adhesive interface. In these areas, it is not a matter of if, but when, coatings will fail.
The presence of chlorinated hydrocarbons or MIC exacerbates the problem, leading to accelerated in-service corrosion. Thus, it has become apparent that development of salt removers addressed only half of the problem. Salt removers were failing to deliver expected results because complete removal of ionically bonded, hygroscopic contaminants must also address sulfide mechanisms.
SIMPLE SOLUTION
OxNot eliminates problematic contamination leading to premature coating failure, rapid rustback caused by high levels of soluble salts, sulfates, nitrates, and microbials but was initially developed to removing sulfide compounds associated “hidden” salts, thus passivating surfaces and allowing metal substrates to remain in a passivated state beneath cured coatings, providing a previously unattainable boost to actualizing consistent coating performance.
Coatings performance is enhanced by realizing an extremely high level of metal hygiene in two ways. First, coatings unimpeded by microcontaminants are better able to establish continuous contact with substrates at the adhesive interface to facilitate stronger, more consistent bonding. Secondly, corrosion is prevented from initiating under and damaging, coatings during service. Strongly and continuous coating bond with substrate metals that remain strongly bonded tend to create a more effective and longer lasting barrier to moisture, regardless of the coating type.
Laboratory testing and case studies conducted over a decade in challenging oil and gas field environments confirmed the efficacy of this new approach. Particularly pertinent to field operations, OxNot LiquidBlast was specifically developed as an additive to enable one process, zero dwell time metal surface cleaning and decontamination during WAVB. Products such as OxNot 207 have also been developed for use as post-abrasive blast and hydro-jetting processes to eliminate the need for bulk and expensive dehumidification and adhesion-impairing corrosion inhibitors.
For more information, please contact WirxGroup LLC (www.wirxgroupllc.com. General Media: admin@wirxgroupllc.com.
Media Contact
WirxGroup LLC admin@wirxgroupllc.com 866-610-0774 109 Shortline Drive http://www.wirxgroupllc.com
