The role of Pigment in coating

This article mainly lists the functions of physical anti-corrosion pigments, chemical anti-corrosion pigments and neutral pigments in the coating in the form of tables.

categorynamerole in coating
Physical anti-corrosion pigment
Iron oxide red (iron yellow, iron black)Good hiding power, tinting power, light fastness, alkali resistance
Zinc oxide (commonly known as zinc white)Hiding power is second only to titanium dioxide and lithopone, good tinting power, heat resistance, light resistance, no discoloration, no chalking, strong rust resistance
Aluminum powder ( commonly known as silver powder )It can prevent the surrounding moisture from penetrating and resist ultraviolet rays. It not only protects the substrate, but also makes the main film-forming substances not easy to fall off. It is used in an appropriate amount in the paint (not less than 0.25 kg in 1 liter) as the middle layer and top coat paint, and is suitable for steel and aluminum. The substrate has good protection.                                      
stainless steel powderGood chemical resistance
chemical anti-corrosion pigment
Red lead (lead red)Excellent anti-rust performance (particle size between 2-10 microns), it is a traditional species used for iron-based metal primers, but it is highly toxic and is gradually less used
Acidic barium metaborateIt can replace red lead, and has the characteristics of anti-fouling, anti-virus, anti-chalking and heat resistance.
Zinc Chrome YellowIt is an excellent antirust pigment used in metal primers such as aluminum and magnesium, and can also be used on iron-based metal surfaces. It has good protection in the marine environment, such as used on offshore platforms; but it is easy to be thermally decomposed, and is not suitable for high-temperature baking primers, nor is it suitable for use in chemical atmospheres.
Zinc powder

It has a cathodic protection effect on steel, also known as a sacrificial anti-rust pigment, and its particle size should be within 10 microns. It is suitable for use in the atmosphere, industrial atmosphere and sea water. It is often prepared as a primer with chlorinated rubber, polyurethane and water glass. , the relative density is high, it is necessary to add a suspending agent, or transfer the dry pigment into the paint base before use

neutral pigment
Titanium dioxide

Strong hiding power, strong tinting power, light resistance, heat resistance, alkali resistance, dilute acid resistance, weather resistance, color retention, chalking resistance

Barite powder ( barium sulfate )Acid-resistant, alkali-resistant, and UV-resistant, it can make the coating film firm and wear-resistant, but the relative density is too high and it is easy to sink to the bottom. For primer, putty, acid-resistant paint


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