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Is epoxy zinc-rich primer an anti-rust paint?
03-28
In the literal sense, anti-rust paint is to prevent metal from rusting. Epoxy zinc-rich primer is a heavy-duty anti-corrosion primer and is often used on metals. The anti-rust performance of epoxy zinc-rich primer is still very strong. The chemical reaction of zinc powder plays a very important role in the anti-rust of metals. Now Sanhui Paint will show you how epoxy zinc-rich primer prevents rust.
1. The role of zinc powder
Epoxy zinc-rich primer contains a large amount of zinc powder. The zinc particles are in close contact with each other and with the steel surface. The potential of zinc is more negative than that of iron, so zinc atoms easily lose electrons in the electrolyte solution and become anodes, while iron is cathodes. In the anode area, zinc is corroded due to the loss of electrons, while in the cathode area, the steel surface continuously gains electrons and is thus protected. In order for the coating to be conductive and play the role of a sacrificial anode, the entire coating must have good conductivity so that the entire coating and the steel substrate system form an electrochemical circuit, and the zinc-rich coating can play an electrochemical protective role.
2. The role of shielding
The shielding effect of epoxy zinc-rich primer mainly relies on the generation of insoluble salts and corrosion products. Traditional zinc-rich coatings use spherical zinc powder, which transmits electrons in the form of point contact and also maintains point contact with the steel substrate. Due to point contact, the conductivity of the coating is poor. In order to improve the conductivity of the coating, a large amount of zinc powder must be added. At this time, the volume concentration of zinc powder far exceeds the CPVC, and the binder is not enough to fill the gaps between the coatings, thus forming a porous coating structure. Now, flaky zinc powder is mostly used to enhance the physical shielding effect, because the addition of flaky zinc powder increases the penetration distance while forming countless tiny areas in the coating, reducing the difference in thermal expansion coefficient between the coating and the metal substrate, reducing the shrinkage rate of the coating during hardening, the stress inside the coating, inhibiting the cracking and shedding of the coating, and improving the adhesion and resistance to medium penetration of the coating, thereby improving the corrosion resistance of the coating.
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©2023 Huirui Environmental Protection Coating (Shanghai) Co., Ltd.
©2023 Huirui Environmental Protection Coating (Shanghai) Co., Ltd.
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