Paints/finishes

Most ventilators are made of aluminum because of its good corrosion resistance and lightweight. On industrial premises they are normally left in mill finishes and allowed to oxidize. On commercial premises, a polypowder paint finish is normally specified for aesthetic reasons. To reduce energy losses during the heating... 

By the use of many commercial abrasive processes, the corrosion resistance of magnesium alloys can be reduced to such an extent that samples of metal that may lie quiescent in salt water for many hours will, after shot blasting, evolve hydrogen vigorously, and the corrosion rate, as measured by loss of weight, will be found to have increased many hundred-fold. The effect in normal atmospheres is naturally much less, yet the activation of the surface is an added hazard and is the opposite of passivation which is essential if later-applied paint finishes are to have proper durability. 

Paint Finishes for Structural Steel for Atmospheric Exposure... 

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