Corrosion Behavior of Different Metals in Salt Spray Environment

Salt spray testing uses a fine mist of saltwater to mimic tough, corrosive conditions—like ocean air. Here's how common metals hold up:

1. Carbon Steel

• Rusts quickly in salty air

• Forms red rust that doesn’t protect the surface

• Needs coating to last longer

2. Stainless Steel

• Has a protective layer to resist rust

• Can still get pitting if scratched

• 316 grade resists salt better than 304

3. Aluminum

• Forms a natural oxide layer for protection

• Can still get small pits in salty conditions

• Lightweight and good for outdoor use

4. Zinc / Galvanized Steel

• Protects steel by corroding first

• Forms white rust, which is protective

• Great for outdoor and marine use

5. Copper & Alloys (Brass, Bronze)

• Rusts slowly and builds a greenish patina

• Good for decorative and durable uses

• Some types may have special corrosion issues

6. Magnesium Alloys

• Corrodes fast in salty air

• Must be coated or treated

• Used in aerospace and lightweight parts