Pipeline Corrosion Mitigation Advances Beyond Traditional Protective Coatings
By G. ROSCIOLI, Arculus Solutions, Arlington, Virginia (U.S.)
(P&GJ) — Every pipeline operator is acutely aware of—and actively plans for—the challenges that stem from corrosion of essential infrastructure. Internal corrosion accounts for approximately 60% of all corrosion cases (PHMSA), making it a critical focus area.1 A threat this pervasive demands proactive management and a comprehensive approach to effective mitigation.
As the impacts of corrosion have been more closely studied in recent years, mitigation efforts have become increasingly successful, suggesting that prevention, rather than costly reactive management and repair, can both streamline operations and allow integrity management budgets to be allocated more efficiently. In fact, a study conducted by NACE International [more recently known as the Association for Materials Protection and Performance (AMPP)] found that nearly 50% of all corrosion-related costs are preventable. Of these preventable costs, 85% are directly associated with protective coatings—a common barrier technology used to limit internal corrosion to pipelines.
While the complete elimination of internal corrosion is perhaps unrealistic, it can be effectively managed through a combination of preventive measures (i.e., epoxy coatings, protective liners, corrosion inhibitors, etc.) and proactive integrity management practices, such as mechanical and chemical cleaning, in-line inspection, and active monitoring. This article focuses exclusively on prevention strategies, with a particular emphasis on how the expanded use of “sputtering”—a proven technique successfully applied to many other industries—can be an effective tool to prevent internal pipeline corrosion.
Barrier Applications in Pipeline Maintenance
Protective coatings have played a central role in pipeline preservation for decades. Legacy technologies, such as epoxy coatings and polymeric liners, have routinely extended pipeline service life and minimized maintenance at an affordable price point, providing a solid foundation for corrosion prevention.
LEGACY SOLUTIONS
Epoxy coatings are polymer-based protective layers that cure into a hard, durable film on the internal surface of a pipeline. Once applied and properly cured, this layer bonds to the metal substrate and acts as a barrier against moisture, oxygen, and corrosive chemicals.
Plastic liners, on the other hand, are sheets of plastic inserted into a pipeline to physically separate the metal from corrosive substances. These liners are particularly effective in chemically aggressive environments.
Both epoxy coatings and plastic liners are cost-effective and well-established technologies. However, their application requires intensive surface preparation, controlled curing environments, and often requires the pipeline to be taken offline. As such, new alternatives have been developed to increase effectiveness and reduce known shortcomings of these established techniques.
Emerging Innovations in Coating Technologies
Recent advancements in materials science have led to the development of several innovative coating technologies.
Self-healing coatings can autonomously repair minor damage, thereby extending the service life of the coating and reducing the need for frequent maintenance.
The integration of nanotechnology has made significant contributions to coating performance. The incorporation of nanoparticles into coating formulations can enhance corrosion resistance, impart antimicrobial properties, and improve mechanical strength.
Bio-based and sustainable coatings, derived from renewable resources, are also becoming increasingly viable. These coatings align with industry sustainability goals while maintaining high levels of protection.
Finally, sputtering, or the application of ultra-thin metallic compounds—such as aluminum oxide—chemically bonds to the substrate and has emerged as a viable method of internal pipeline corrosion management.
Sputtering: A Molecularly Bonded Barrier Against Corrosion
Sputtering is a physical vapor deposition (PVD) technique that enables the formation of a uniform thin film barrier layer on a substrate—in this case, the internal diameter (ID) of a pipeline. The method involves ejecting atoms from a solid target material onto the substrate to form a corrosion barrier at the molecular level. While its use in the energy pipeline industry is new, sputtering has been widely used in various industries for decades, including microelectronics, aerospace, and the medical device industry.
Magnetron Sputtering for Pipelines
There are several types of sputtering techniques, including reactive sputtering, ion beam sputtering, and magnetron sputtering. Each method offers specific advantages depending on the application and desired characteristics. Magnetron sputtering is particularly well-suited for pipeline applications because of the powerful adhesion achieved between the film and the substrate, as well as the resulting compactness and uniform film formation.
The technique, which was first introduced in the 1970s, allows for the simultaneous sputtering of different metals, alloys, and oxides onto the substrate via a vacuum-based process.2 Magnetron sputtering is considered the most important physical deposition process for depositing oxide layers and has emerged as the leading coating technology for various applications, due to its numerous advantages.2 For pipeline applications, the applied aluminum oxide compound, deposited in situ via a highly sophisticated pig, produces a uniform barrier that is ultra-thin and molecularly bonded to the substrate (the internal pipe surface).
The alumina—or aluminum oxide—film is deposited on the internal pipe wall and acts as a corrosion barrier with a composition that cannot be penetrated, unlike other coatings. It is extremely thin, less than the width of a human hair. The barrier’s molecular structure means that its thickness has no bearing on overall strength or function. Furthermore, it cannot flake off, delaminate, crack, or wear over time as would a typical coating—essentially blocking corrosive substances from reaching the pipe wall. In short, its chemical composition prevents corrosion from developing.
The magnetron sputtering technique offers several advantages for pipeline corrosion prevention. The deposited alumina barrier significantly reduces the friction factor—by as much as 30%—compared to the untreated pipe ID. Additionally, it does not require cure time and is unaffected by humidity or extreme temperatures. Finally, it can be noted that this ultra-thin barrier layer has negligible impact on the production capacity of a pipeline, compared to other methods, such as liners, which reduce the pipe’s ID and thereby its overall capacity.
The Future of Sputtering in the Pipeline Industry
Sputtering has the potential to redefine corrosion prevention strategies in the pipeline industry. This sustainable, scalable method of corrosion mitigation can prevent internal pipeline corrosion from developing into a severe—and costly—problem. Proactive corrosion management and prevention, rather than reactive response to accelerating damage, can facilitate leaner, more efficient integrity budgets and less service interruptions for critical pipeline infrastructure. By reducing the prevalence of internal corrosion within critical pipeline infrastructure, pipeline operators can observe extended service lives for these critical assets. Even as infrastructure demands grow, sputtering stands out as a scalable, high-performance solution that addresses both technical and economic challenges in corrosion mitigation.
LITERATURE CITED
1 Pipeline and Hazardous Materials Safety Administration. phmsa.dot.gov. https://www.phmsa.dot.gov/
2 Garg, R., Gonuguntla, S., Sk, S., Iqbal, M. S., Dada, A. O., Pal, U. and M. Ahmadipour, “Sputtering thin films: Materials, applications, challenges and future directions,” ScienceDirect, August 2024, online: https://www.sciencedirect.com/science/article/abs/pii/S000186862400126X
About the Author
GIANLUCA ROSCIOLI brings nearly a decade of materials engineering and metallurgy research experience, specializing in the design and fabrication of setups for onsite scanning electron microscopy experiments and failure analysis. He holds a Sc.D. in materials science and engineering from MIT, and dual M.Sc. degrees in materials engineering and nanotechnology from Politecnico di Milano and in Materials Engineering from Politecnico di Torino.