In the unforgiving depths of the ocean, corrosion and pressure are relentless adversaries, presenting unique challenges for submarine shipboard systems. Durable, high-performance valves on their own are not enough to ensure long-lasting, reliable performance. Corrosion-resistant valve coatings also play an invaluable role to bring out the best in the critical systems you build.
Read on for a detailed dive into how valve coatings work to protect submarine systems from premature failure, especially coatings ideal for seawater corrosion control such as ceramic coating, and how you can take advantage of them to build more resilient naval systems.
Understanding the Challenges of Submarine Environments
In marine environments, valve protection is paramount. Seawater corrosion is an ever-present threat, even for systems that are not directly exposed to seawater. Valves for critical shipboard systems must be able to perform reliably and provide a long service lifespan despite the corrosive effects of seawater exposure and salt and moisture in the air.
Mil-spec naval valves accomplish this with high-quality ASTM-rated materials selected for corrosion resistance, valve bodies designed to simplify cleaning, and detailed maintenance protocols. But in especially extreme applications, such as subsea environments, durable valve materials and thorough, regular maintenance alone won’t cut it.
Naval submarines, for example, or underwater oil and gas infrastructure face unique environmental challenges. Deep-sea and ultra-deep-sea applications 1,000 or 2,000 feet below sea level expose valves to not only corrosive saltwater, but high external pressures that cause metal embrittlement and weaken the elasticity of plastic seals. On top of that, submarine valves can be difficult to access for routine maintenance, but still need to provide two decades or more of reliable service.
How Valve Coatings Provide Seawater Valve Protection
In these extreme subsea environments, corrosion-resistant valve coatings are one of the most powerful solutions to the problems valves face in these harsh operating environments. The coatings used in naval submarines and offshore industrial applications provide:
- A strong barrier between your valve’s metal body and seawater and dissolved chlorides
- Minimal risks of pitting corrosion and stress cracking
- Reduced wear and galling on valve surfaces in high-pressure conditions
- Reduced friction between moving parts within the valve for improved efficiency
Valve coatings for seawater corrosion control come in a wide range of types, including:
- High-velocity oxygen-fuel coating, a thermal spray process that covers your valve body in a very dense, very hard coating ideal for providing corrosion protection and wear resistance in high-pressure, high-temperature environments.
- Fusion-bonded epoxy coating, which uses an epoxy-based powder to create a tough, uniform barrier layer to protect saltwater valve components from corrosion in deepwater environments. FBE coatings can be applied to both external and internal valve surfaces and can be layered with other coatings.
- Polyurethane coating, which provides strong, elastic coatings for seals and gaskets that protect against abrasion and impact without compromising flexibility.
- PTFE coatings, which offer a highly chemical-resistant, low-friction coating with good thermal stability
- Zinc/aluminum metalizing, which protects against galvanic corrosion by creating a sacrificial anode—a coating that corrodes when exposed to seawater environments, while preventing the valve body underneath from corroding
- Ceramic coating, which provides protective thin-film layers of ceramic material to increase resistance to wear, lower friction between moving parts, and minimize corrosion.
For the US Navy, ceramic thermal spray coatings have become increasingly demanded as a protective submarine valve coating.
Ceramic Coating: The Key to the Durability of Submarine Valves
Ceramic materials such as aluminum oxide, zirconium dioxide, and silicon carbine are hard, stable, and resist various types of degradation. When valve coatings for submarines use these materials, they reap the benefits of an extremely hard barrier layer that withstands seawater and other aggressive chemicals found in naval environments.
Because ceramics also offer excellent thermal insulating properties, submarine valves can endure varying temperature conditions without losing their structural integrity. On top of that, ceramic coatings are generally non-reactive with other materials, reducing risks of chemical reactions that could compromise them or damage the valve.
As a result, ceramic submarine valve coatings offer:
- A significantly extended service life
- Less frequent needs for maintenance and replacement
- Consistent performance in critical naval operations
How to Apply Ceramic Valve Coatings
The most common way to apply ceramic coatings to submarine valves is via plasma spraying. This application technique involves heating ceramic powder using a plasma torch and spraying it onto the valve surfaces. As the ceramic particles melt, they form a continuous coating that hardens into a strong barrier layer. Similarly, thermal spraying uses a heat source to project molten ceramic particles onto the valve surfaces.
Another way ceramic coatings can be applied to a valve is through chemical vapor deposition, which deposits a thin layer of vaporized ceramic particles on the valve surface. Through the use of vapor deposition technology, the particles form an extremely thin, extremely uniform, and extremely high-purity coating.
Mil-Spec Valves for Marine and Submarine Environments
High-quality valve materials, submarine valve coatings, and regular maintenance together ensure long-lasting, reliable performance for the most critical valves in the most essential deep-sea systems.
Since the 1980s, Dante Valve has been a leading manufacturer and supplier of durable, high-efficiency valves to the US Navy and naval shipbuilders across the US. Our line of military-spec valves meets every required standard for naval operations on the water and beneath it. With decades of expertise in marine environments, we can help you choose the right valves and make coating decisions to ensure the protection you need in the most demanding marine environments.