A method of forming a passivated pigment slurry includes combining a resin and a pigment to form a pigment-resin slurry, wherein the pigment includes a plurality of flakes each having a surface. After combining, the method includes mixing the pigment-resin slurry and an orthosilicate to form a coated pigment-resin slurry. The coated pigment-resin slurry includes the resin and a coated pigment including the plurality of flakes each encapsulated by a first layer formed from silica and disposed on the surface. The method further includes reacting the coated pigment-resin slurry and an organosilane compound having a hydrolysable group and an organic functional group to coat the first layer and thereby form the passivated pigment slurry. The passivated pigment slurry includes the resin and a passivated pigment including the plurality of flakes each coated with a second layer disposed on the first layer.