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.
| category | name | role 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 powder | Good 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 metaborate | It can replace red lead, and has the characteristics of anti-fouling, anti-virus, anti-chalking and heat resistance. | |
| Zinc Chrome Yellow | It 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 |
- 1Summary of determination methods for hiding power of coatings
- 2Pigment hiding power
- 3Determination of Coating hiding power
- 4GB/T 23981.2-2023: Paints and varnishes - Determination of hiding power - Part 2: Checkerboard method - Interpretation
- 5Concept, influencing factors and determination method of Coating hiding power
- 6Mayer Rods: The right-hand man for hiding power tests
- 7Coating performance testing: ensuring the efficiency and mass of the painting process
- 8Coating hiding power measurement
- 9Application of paint film Applicator in hiding power test
