Aluminum Corrosion Particles

These particles are from a piece of equipment wrapped in plastic and stored in a covered but uncontrolled environment. The particles appear white, clear, or gray. The gray particles contain metal fragments from the corroded aluminum alloy, the particle on the right. The clear particles tend to be alumium hydroxide and the white particles tend to be a mixture of alumium hydroxide and carbonate from reaction with atmospheric carbon dioxide. The refractive index of the particles nearly match that of the mounting medium, approximately 1.50.