The inorganic zinc-rich series paint is composed of inorganic chemical polymers (such as silicates, phosphates, chromates, etc.) as the film-forming material. The zinc powder reacts with these polymers, forming a zinc-iron complex on the surface of metal materials, creating a robust protective coating. The inorganic zinc-rich series paint refers to paints that use inorganic substances as binders, incorporating plasticizers, anti-settling agents, leveling agents, thickeners, and zinc powder, among other additives.
Ethyl silicate or its oligomers, under acidic conditions and with ketones or alcohols as solvents, can absorb and utilize moisture from the air or add a small amount of water to the reaction solution for analysis and hydrolysis. Through condensation reactions, a polymer with a significant molecular size can be generated.
Protection Mechanism:
(1) Electrochemical Protection: The inorganic zinc-rich series paint can provide electrochemical protection due to the extensive use of high purity, fine-grained zinc powder as a filler. Zinc is more reactive than iron and has a more negative potential. In an electrolyte, zinc atoms readily lose electrons. Even if the coating is partially damaged, the steel surface will not corrode as zinc, acting as a sacrificial anode, loses electrons in the anode region, while the cathode region gains electrons, thereby protecting the steel from environmental corrosion.
(2) Excellent chemical stability: The inorganic zinc-rich series coatings, using ethyl silicate or oligomers as film-forming materials, offer good adhesion to steel surfaces, resistance to heat and corrosion, resistance to aging, and excellent weatherability. Additionally, zinc powder forms highly insoluble stable substances such as zinc salts and zinc complexes on the coating surface, preventing steel from being corroded by oxygen, water, and salts.
Inorganic zinc-rich paint offers electrochemical protection to steel, boasting excellent anti-corrosion, seawater resistance, oil resistance, solvent resistance, salt resistance, and atmospheric corrosion resistance. It can be used for extended periods at temperatures up to 400°C and is widely researched and applied in China's shipbuilding industry, petrochemical engineering at universities, and for thermal pipelines, chimneys, bridges, and other marine infrastructure.
Construction Precautions:
1. Surface Treatment: Prior to rust removal, all welding slag, burrs, oil stains, and all machine work burrs should be removed. The steel surface should be sandblasted or shot-peened (sandblasting) for rust removal. The rust removal grade should reach Sa3 level as specified in GB/T8923, with the steel surface roughness being RZ25～60μm.
2. Paint Preparation:
Based on the specified paint volume, calculate the total amount according to the required spray area, and strictly adhere to the ratio of each component during each paint mixing.
Before use, the paint must be thoroughly mixed.
Construction Precautions:
Coating operations should be conducted under conditions of ample lighting, good ventilation, and a clean work surface.
The relative humidity in the work area varies less than 90%, with the environment and humidity controlled between 5-35°C.
After the paint surface dries, apply the curing agent by brushing or spraying, ensuring the surface is not over-wetted.
The steel components with the sprayed coating should be flipped or stacked after 24 hours of drying to prevent damage to the coating.
