Selective leaching
Selective corrosion is a specific type of rusting where only certain metal components of an alloy corrode. This leads to a porous structure and degraded mechanical properties.
Physicochemical Mechanism of Action
Selective corrosion occurs when specific metal components in an alloy (e.g., steel with copper alloys) corrode more in a corrosive environment than others. This happens because the more susceptible component has a higher affinity for electrons, oxidizing faster.
Metallurgical Relevance & Risks in Welding
Selective corrosion can lead to a highly porous residual structure, significantly reducing strength and toughness. This increases the risk of cracking and failure under mechanical stress. Additionally, it can form compounds that further damage the material.
Workshop Practice & Instructions
To prevent selective corrosion, it is crucial to ensure proper weld seams and thorough cleaning of components. Use appropriate protective measures and control cooling. For specific alloys, especially copper alloys, it is vital to maintain corrosion protection.