Metallic pigments supply form

Corrosion control by pigments relies on well-known principles of corrosion inhibition. Iron and steel exposed to air are quickly covered by an oxide film aqueous electrolytes tend to break down this film, and further oxidation of the metal surface ensues. The role of anodic corrosion inhibitors is to supplement or to aid in the repair of the surface oxide film. Basic pigments may form soaps, for example, with linseed oil autoxidation of these soaps may yield soluble inhibitors in the film. Some other pigments of limited solubility act directly as inhibitors. Active metal pigments supply electrons to the iron substrate and thus lower its potential and prevent metal dissolution. 

Metal effect pigments are flake-shaped metallic particles supplied in the form of powders, pastes, pellets, suspensions or color concentrates [5.166-5.168]. Typical metal effect pigments include aluminum ( silver bronze ) and copper- and copper/zinc-alloys ( gold bronze ). 

The metal pigments, gold bronze as well as aluminum, are supplied in the form of powders, pastes (including solvents), granules (including resins), suspensions (VMPs), color concentrates or even press-ready printing inks. 

Aluminum pigments are the most often used metallic pigment in surface coatings. They are prepared from high purity aluminum metal by ball milling fine aluminum powder in the presence of a hydrocarbon solvent and grinding aids such as stearic acid and then formed into platelet-shaped particles. They are normally supplied as pastes in hydrocarbon solvents and occasionally in powder form. 

The iron content of the body is 4—5g. Most of it is present in the hemoglobin (blood) and myoglobin (muscle tissue) pigments. The metal is also present in a number of enzymes (peroxidase, catalase, hydroxylases and flavine enzymes), hence it is an essential ingredient of the daily diet. The iron requirement depends on the age and sex of the individual, it is about 1.5-2.2 mg/day. Iron supplied in the diet must be in the range of 15 mg/day in order to meet this daily requirement. The large variation in intake can be explained by different extents of absorption of the various forms of iron present in food (organic iron compounds vs simple... 

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