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Several anti-corrosion effects of rust-inhibiting pigments usually exist simultaneously, and their anti-corrosion mechanisms include the following three aspects: physical, chemical, and electrochemical. Physical corrosion protection: By appropriately combining pigments that react with oily film-forming agents, a dense corrosion-resistant coating can be created, thereby enhancing the physical corrosion protection effect. For example, lead-containing pigments react with oils to form lead soaps, which make the anti-corrosion coating denser and thereby reduce the penetration of harmful substances such as water and oxygen. Phosphate pigments, upon hydrolysis, form insoluble basic salts that act to block pores in anti-corrosion coatings. Iron oxides, or pigment fillers such as flaky mica powder, aluminum powder, and glass flakes, can all reduce the permeability of anti-corrosion coatings, providing physical protection against corrosion. Chemical corrosion prevention: When harmful acidic or alkaline substances penetrate the anti-corrosion coating, it can neutralize them and turn them into harmless substances; this is also an effective method of corrosion prevention. In particular, by cleverly using amphoteric compounds such as zinc oxide, aluminum hydroxide, and barium hydroxide, it is possible to easily neutralize acidic or alkaline harmful substances to exert a preservative effect, or to react with water and acids to produce alkaline substances. These alkaline substances adsorb on the surface of steel, keeping it alkaline; in an alkaline environment, steel is less prone to rusting. The electrochemical corrosion protection mechanism works by means of water and oxygen that penetrate through the pores in the coating; as these substances pass through the anti-corrosion coating, they react with the rust-inhibiting pigments dispersed within it to form anti-corrosion ions. This moisture containing preservative ions reaches the metal surface, causing the steel surface to become passivated (raising its potential) and preventing the dissolution of iron ions; chromate pigments possess this property. Alternatively, metals with an electrode potential lower than that of steel can be used to protect steel; for example, zinc-rich coatings function as sacrificial anodes because zinc has a lower electrode potential than steel, which prevents the steel from corroding easily.