In the harsh world of chemical processing, chloride corrosion is a relentless aggressor. Whether it’s from hydrochloric acid exposure or salty coastal conditions, chlorine-based compounds pose a significant threat to the integrity and longevity of process sampling systems, analyzers, structures, and safety. At SilcoTek, we understand how vital it is to maintain system reliability and accurate sampling, which is why we offer various coating solutions tailored to specific applications, ensuring both corrosion resistance and chemical inertness.
Chloride corrosion—also known as pitting or crevice corrosion—is a localized form of attack that aggressively penetrates stainless steel surfaces, particularly 300-series alloys like 304 and 316. While these materials are commonly used due to their general corrosion resistance, they fall short under prolonged chloride exposure.
In real-world process environments, this means systems can fail in just days when subjected to high-chloride conditions, with consequences like leaks and system failure, contaminated or inaccurate samples, downtime and costly repairs, or shortened component lifespan. Even minor surface degradation can lead to sample adsorption, carryover, or contamination - compromising not only the equipment but the analytical results as well.
The exceptional chloride resistance of silicon CVD coatings like Dursan®, Siltride® 1000, or Silcolloy® 2000 can prevent salt-related corrosive attack. The 4000 hour salt spray comparison below demonstrates the improvement a protective coating can have on sample transfer systems. The uncoated test coupons (left) show significant corrosion while the Silcolloy-coated coupon shows very light rust spots. Dursan-coated coupons remain corrosion-free.
Other chloride containing streams can greatly reduce the lifetime of process systems. The corrosion graph below provides the results obtained from ASTM G31 testing of common sample flow path materials. The immersion test in a 6M HCl (18%) solution at 50° C and atmospheric pressure can quickly damage stainless steel surfaces. Dursan-coated stainless steel performs at levels comparable to high-quality super alloys, reducing corrosion rate from 3116 mills per year to 23 mpy. Dursan-coated stainless steel demonstrated over 200x greater resistance to 6M HCl than uncoated stainless steel. It also holds up under high-flow and abrasive conditions, extending component life and reducing total cost of ownership.
After immersion, differential weighing allows the amount of material loss to be determined. The amorphous silicon-coated stainless steel shows greater than 20 times the resistance of non-treated stainless steel in these environments.
This is where SilcoTek’s advanced coatings, particularly passivated Dursan, change the game. Dursan is a silicon-based, chemically bonded coating engineered to dramatically improve corrosion resistance while maintaining surface inertness.
Other coating benefits include:
SilcoTek coatings are ideal for:
Protecting these critical components helps eliminate sample loss, boosts equipment reliability, and enhances process safety.
Corrosion from chlorine compounds doesn’t have to be an inevitable failure point. With Dursan and other SilcoTek coatings, you can equip your process analyzers and sampling systems to resist chloride attack while maintaining peak performance.
Don’t wait for corrosion to eat away at your system - get in touch with our team today and extend the life of your equipment from the inside out.