Which colors describe the oxide layers on aluminum and iron respectively, as given in the material?

Which colors describe the oxide layers on aluminum and iron respectively, as given in the material?

• A. White and red
• B. Black and reddish
• C. Red and grey
• D. White and black

Answer: (B)

Oxide films tell you how clean and prepared the surface is before welding, and their colors reflect the type of metal and the oxide thickness. In this material, the oxide on aluminum is described as black, while the oxide on iron is described as reddish. That pairing—black for aluminum and reddish for iron—best matches what the material states. Other color combinations don’t align with those described oxide colors.

Oxide films tell you how clean and prepared the surface is before welding, and their colors reflect the type of metal and the oxide thickness. In this material, the oxide on aluminum is described as black, while the oxide on iron is described as reddish. That pairing—black for aluminum and reddish for iron—best matches what the material states. Other color combinations don’t align with those described oxide colors.