Final answer:
In power transmission line maintenance, a grease compound is used to fill the outer splice after connecting steel core and aluminum wires to protect against oxidation and corrosion.
Step-by-step explanation:
In the context of overhead transmission line maintenance, oxidation of splices is a major concern due to the deteriorative effects it has on the materials used. To combat this, special materials are used to fill the space after splicing. When finishing the outer splice on a steel core wire surrounded by aluminum, a grease compound is commonly used to fill the splice. This grease acts as a barrier preventing oxygen and water from coming into contact with the metal, thereby significantly slowing down the corrosion process.
Other methods for protecting metals from corrosion include the application of paints, plastics, cathodic protection with zinc or magnesium, and the use of metal alloys such as stainless steel. However, for the specific case of splicing in power transmission lines, a grease compound is preferred for its effectiveness and ease of application.