What is the process that can turn a strong, shiny metal object into a pile of powder?

The process that can turn a strong, shiny metal object into a pile of powder is corrosion. This phenomenon occurs when metals react with their environment, particularly in the presence of moisture or other elements. Over time, corrosion can break down the structural integrity of the metal, leading to the formation of weaker compounds or powders that can flake off.

Corrosion is a gradual process that typically involves multiple chemical reactions, resulting in the deterioration of the metal's properties, often making it porous and reducing it to a powder-like form after significant exposure to corrosive agents. This is distinct from oxidation, which primarily refers to the reaction of a metal with oxygen, and while it can contribute to corrosion, it is not exclusively the process that results in powder formation.

Erosion, on the other hand, describes the physical wear and tear caused by environmental factors such as wind or water, which does not chemically alter the metal into powder. Rusting is specifically the oxidation of iron in the presence of water and oxygen, creating iron oxide, but it doesn't universally apply to all metals and is not defined by powdered metal formation.