The corrosion mechanism of mercury on aluminum primarily involves which process?

• A. Formation of an oxide layer on aluminum
• B. Amalgamation with aluminum
• C. Oxidation of mercury
• D. No reaction

Answer: (B)

Mercury corrodes aluminum mainly through amalgamation, the process of mercury dissolving aluminum to form a liquid alloy at the interface. Aluminum relies on a thin protective oxide film, but mercury can penetrate and disrupt that film. As the amalgam forms, aluminum atoms are pulled into the mercury, removing them from the metal lattice and creating pits that rapidly weaken the structure. This interfacial alloying is the primary damage mechanism, not the formation of more oxide on aluminum or oxidation of mercury. So, the key idea is that mercury chemically combines with aluminum to form an amalgam, driving corrosion.