The application of current to a pipeline helps to create which effect in cathodic protection?

In cathodic protection, the application of current to a pipeline primarily serves to create a protective barrier against corrosion. This process involves supplying a negative charge to the pipeline, which reduces the electrochemical reactions that lead to corrosion. The protective barrier effectively slows down or halts the corrosive processes that would otherwise damage the metal surface of the pipeline.

Cathodic protection can be achieved through impressed current systems or sacrificial anode systems. In both cases, the aim is to ensure that the structure being protected (in this case, the pipeline) becomes the cathode of an electrochemical cell, thereby preventing corrosion and extending the lifespan of the pipeline.

While electrical flow, insulating layers, and thermal reactions may play roles in the overall functioning of pipelines or be involved in other processes, they do not directly relate to the specific purpose and effect of applying current in the context of cathodic protection. The main focus is on the creation of that protective environment, which mitigates the factors leading to pipeline degradation.