Cylinder couplings are made of nickel-plated brass instead of pure brass, mainly based on the following advantages:
1. Significantly improve corrosion resistance
Limitations of brass: brass (copper-zinc alloy) itself is susceptible to moisture, acidic or alkaline media corrosion, long-term use may produce patina or oxide layer, resulting in a decline in sealing or contamination of the medium.
Advantage of nickel plating: nickel layer has excellent corrosion resistance to water, oxygen, weak acids and alkalis and some chemical media, especially suitable for high-pressure gases, high-purity gases or corrosive environments (e.g., industrial, medical fields).
2. Enhanced wear resistance and sealing
The hardness of nickel is higher than brass (nickel hardness is about HV200-300, brass is about HV100-120), nickel-plated joints are more resistant to repeated insertion and removal, friction, and prolong the service life.
The smooth surface of nickel-plated layer can reduce the microscopic leakage of the sealing surface and enhance the airtightness, which is crucial for high pressure or flammable and explosive gases (e.g. hydrogen, oxygen).
3. Protection against copper ion contamination
In the food, pharmaceutical or electronics industries, copper ions can contaminate high-purity gases or liquids (e.g. semiconductor manufacturing, oxygen for breathing). Nickel plating blocks copper migration and meets cleanliness requirements.
4. Aesthetics and tarnish prevention
Brass is easy to oxidise and tarnish, nickel plating maintains a silvery-white metallic luster for a cleaner appearance, which is suitable for occasions where aesthetics are required (e.g. laboratory equipment).
5. Balance of cost and performance
Full nickel fittings are too costly, while nickel-plated brass retains the good machinability of brass (easy to form, low cost) while improving key performance through surface treatment, which is more cost-effective.
Typical application scenarios
High-pressure gas cylinders: such as industrial oxygen, acetylene, argon, etc., need to prevent corrosion and sealing.
Medical equipment: avoid copper contamination and need frequent disinfection (nickel plating resistant to alcohol, disinfectant).
Special environment: marine, chemical and other humid or corrosive occasions.
Precautions
Plating quality: If the nickel plating process is poor (e.g. insufficient thickness, poor bonding), it may peel off and accelerate corrosion. Select plating that meets standards (e.g. ASTM B733).
Compatibility: some media (such as hydrogen sulphide) may react with nickel, it is necessary to choose other plating (such as chromium plating) or stainless steel.
In summary, nickel-plated brass fittings outperform pure brass in most scenarios and are the preferred solution for reliability, economy and safety.
Post time: Apr-28-2025