Which protective coating is associated with military corrosion/anti-wear protection and has restrictions on use?

• A. Zinc plating
• B. Cadmium plating
• C. Anodizing
• D. Electroless nickel plating

Answer: (B)

Cadmium plating is known for its excellent combination of corrosion resistance and anti-wear/low-friction properties, which is why it’s used on military hardware and components that must endure harsh salt-spray environments and sliding contacts. It acts as a sacrificial coating, protecting the underlying metal by preferentially corroding and providing a lubricious surface in wear-prone areas. However, cadmium and its compounds are highly toxic, leading to strict restrictions on use, handling, and disposal under environmental and safety regulations. Because of these restrictions, cadmium plating is limited to certain essential applications and is often being replaced by other coatings where permissible, whereas other coatings like zinc plating, anodizing, or electroless nickel plating do not carry the same combination of military-specific protection and regulatory constraints.