Which statement about aluminum as a coating is true?

• A. Aluminum cannot be used as a coating for any metal.
• B. Aluminum coatings require ceramics.
• C. Aluminum can be used as a coating for different metals.
• D. Aluminum coatings are always brittle.

Answer: (C)

Aluminum as a coating is versatile because it can protect a variety of substrates. It works by forming a stable, adherent oxide layer and acting as a diffusion barrier, which helps prevent corrosion of the underlying metal. This coating can be applied to different metals such as steel, iron, copper, and others through methods like hot-dip aluminum, electroplating, or thermal spraying, making it common across many substrate types. The other ideas don’t fit: aluminum coatings don’t require ceramics—the coating itself can be metallic and still provide protection—and they aren’t inherently brittle—their ductility depends on thickness, deposition method, and substrate compatibility.