Which protection method protects steel tank bottoms from corrosion by applying an external current?

Which protection method protects steel tank bottoms from corrosion by applying an external current?

• A. Sacrificial anode protection
• B. Impressed cathodic protection
• C. Epoxy coating
• D. Thermal insulation

Answer: (B)

Impressed current cathodic protection protects steel tank bottoms by applying an external current. In this method, a power source drives direct current to protective anodes around the tank, pushing electrons into the steel and making its surface more cathodic. This lowers the metal’s tendency to oxidize, so corrosion at the bottom is suppressed even in harsh soils or wet environments. Sacrificial anode protection also protects steel but relies on a more active metal corroding in place of the steel, without using an external power supply. Epoxy coating provides a barrier to environment but doesn’t involve current flow. Thermal insulation is not a corrosion-protection strategy and does not depend on current.

Impressed current cathodic protection protects steel tank bottoms by applying an external current. In this method, a power source drives direct current to protective anodes around the tank, pushing electrons into the steel and making its surface more cathodic. This lowers the metal’s tendency to oxidize, so corrosion at the bottom is suppressed even in harsh soils or wet environments.

Sacrificial anode protection also protects steel but relies on a more active metal corroding in place of the steel, without using an external power supply. Epoxy coating provides a barrier to environment but doesn’t involve current flow. Thermal insulation is not a corrosion-protection strategy and does not depend on current.