Acrylic coating powders comprising hydrophobic particles and powder coatings therefrom having filliform corrosion resistance

The present invention provides coating powder compositions for making filiform corrosion resistant coatings, the compositions comprising particles or agglomerates which include, intimately mixed, each of one or more thermosetting acrylic copolymer, one or more crosslinker for the acrylic copolymer and one or more hydrophobic submicron particle additive, wherein the hydrophobic submicron particle additive comprises from 0.01 to 1.5 wt.%, based on the total weight of the coating powder. The hydrophobic submicron particle additive comprises a submicron inorganic oxide, e.g. fume silica or a metal oxide, and one or more organosilicon compound, e.g. polydimethylsiloxane. In addition, the invention provides filiform corrosion resistant clear coat or tinted clear coat powder coatings on metal, e.g. aluminum wheels or forged alloy substrates.