Patent ID: 8701879

Claim:
A capsule-in-capsule structure comprising a closed outer capsule with a closed outer frangible capsule shell and a closed inner capsule with a closed inner frangible capsule shell, the closed inner capsule shell containing a first reactant and the closed outer capsule shell containing a second reactant and the closed inner capsule, the first and second capsule shells being adapted to hold separate the first and second reactants; wherein a rupture-producing event suitable for rupturing of one or other of the outer or inner capsules will also immediately rupture the other of the outer or inner capsules; and the first reactant is Ce 2 O 3 , as a solid, and the second reactant is NaNO 2 , as a solid, and at least one of the first and second reactants, upon release, absorbs water when exposed to moisture or humidity, to thereby form an aqueous solution for chemical reaction with a magnesium alloy to form a conversion coating on the magnesium alloy; and the size of the outer capsule is adapted for incorporation in a paint film applied to a magnesium article of manufacture.