How does the corrosion resistance of brass cable glands compare to that of aluminum or stainless steel glands in marine environments?
How does the corrosion resistance of brass cable glands compare to that of aluminum or stainless steel glands in marine environments?
Blog Article
Corrosion Resistance of Brass Cable Glands Compared to Aluminum and Stainless Steel in Seawater Conditions
Seawater exposure speeds up corrosion in marine conditions, so it is imperative that the material of cable glands is carefully chosen to ensure long-term integrity and electrical safety. Brass, aluminum, and stainless steel are three materials commonly used, with differing levels of corrosion resistance.
Brass cable glands are highly corrosion resistant, particularly when they have a nickel or other protective coatings. The inherent characteristics of brass, an alloy of copper and zinc, are highly resistant to rust and oxidation under mildly corrosive sea conditions. Moreover, brass develops a protective patina over a period, adding to its durability. But in very saline conditions, brass can be subject to dezincification, in which the zinc leaches out, causing the structure to deteriorate. This can be prevented by using dezincification-resistant (DZR) brass.
Aluminum cable glands are inexpensive and light in weight but less corrosion-resistant than brass and stainless steel. In marine environments, aluminum is susceptible to pitting and galvanic corrosion if exposed to seawater, particularly if it is exposed to dissimilar metals. Anodized aluminum improves resistance but is still not suitable for extended marine exposure.
Stainless steel cable glands, specifically grades 316 and 304, offer the greatest corrosion resistance of the three materials. 316 stainless steel, with added molybdenum, is extremely resistant to chlorides and seawater and, therefore, the preferred choice for challenging marine environments. It is also pitting-, crevice corrosion-, and stress cracking-resistant. However, stainless steel is heavier and more costly than brass and aluminum.
Conclusion
For mild to moderate sea exposure, brass cable glands with protective coatings are effective. But in highly saline or aggressive applications, 316 stainless steel is the best option because of its unparalleled corrosion resistance and durability. Although affordable, aluminum is not generally suitable for marine use because it is prone to premature corrosion.