It is applied to deposit a chrome-chrome oxide film on the surface of the substrate to increase the corrosion resistance of the product. The total chrome on the surface is measured as weight per area e.g. 300 micrograms per sq.ft. of surface. Customers can order chemical treatment levels within certain ranges from 150 micrograms per sq. Line marking is done using a mixture of approximately 1-4 grams per liter of soda ash and water. This causes a slight change in the rate at which the tin is melted on the surface and the result is marking on the surface.
Standard marking is lines on the heavier coated side or geometric marking on the light coated side.
Matte surface is a dull surface. Reflowed surface is very shiny and reflective. The tin coating has been given a flash heating process at a temperature just above the melting point of tin, wherein the tin melts and refreezes very rapidly, resulting in a reflective surface. Passivated tin plate is the same as chemically treated tin plate. There is some evidence suggesting that certain adhesion failures of epoxy-phenolic lacquers on passivated tin plate are related to a combination of substrate conditions, lacquer formulations and application practices.