In the three-layer protective system of marine anti-corrosion coatings, dán nhôm, with its unique lamellar structure and excellent barrier properties, has become a key functional pigment for improving the corrosion resistance life of coatings. However, the application of aluminum silver paste in primers, intermediate coats, and topcoats is not a "one-size-fits-all" approach, but requires refined and differentiated design based on the functional positioning of each coating.
Anhui Boyan, a high-tech enterprise specializing in the R&D and production of high-performance aluminum silver paste, has been deeply involved in the marine coatings field for many years and deeply understands the core performance requirements of different coating systems for aluminum silver paste. We have developed a series of customized aluminum silver paste products for different marine coating application scenarios, covering multiple categories such as primer-specific, high-additive intermediate coat, and weather-resistant topcoat, helping coating companies build more efficient marine anti-corrosion solutions.
I. Application of Aluminum Silver Paste in Primers: Corrosion Prevention as the Core
Marine primers come into direct contact with the metal substrate, undertaking the dual functions of cathodic protection and physical barrier. The following points should be considered when applying aluminum silver paste in primers:
Dosage Control: The dosage of aluminum silver paste in primers is typically between 8-15%, and it needs to be used in combination with active anti-corrosion pigments such as zinc powder and phosphates. The lamellar structure of aluminum silver paste can extend the penetration path of corrosive media (water, oxygen, chloride ions), forming a "maze effect," while zinc powder provides cathodic protection; the two work synergistically to enhance anti-corrosion performance.
Particle Size Selection: Medium-sized (10-25μm) aluminum silver paste is recommended for primers. This ensures good barrier performance without affecting the adhesion and flexibility of the coating. Too fine a particle size can easily settle, while too coarse a particle size may affect the coating's density.
Surface Treatment: The aluminum silver paste in the primer needs to be coated with a silane coupling agent or silica to enhance the interfacial bonding with the epoxy resin and prevent the generation of hydrogen gas in alkaline environments.
II. Application of Aluminum Silver Paste in Intermediate Coatings: Thickening and Barrier Effect
The main function of intermediate coatings is to increase the total coating thickness and further enhance the barrier effect. The application strategy for aluminum silver paste in intermediate coatings differs from that in primers:
High Addition Levels: The addition level of aluminum pigment in intermediate coatings can be increased to 15-25% to maximize the barrier effect. Since intermediate coatings do not directly contact the substrate, cathodic protection is not required, allowing focus on the physical barrier function.
Thick Film Formulation: Intermediate coatings are typically designed for thick films (single-coat dry film thickness 150-300μm). The flake-like structure of aluminum silver paste effectively prevents coating cracking and pinhole formation. It is recommended to use aluminum silver paste with a large aspect ratio (>100:1) to enhance coating density.
Compatibility: The aluminum silver paste in intermediate coatings must ensure good compatibility with primers and topcoats to avoid interlayer adhesion problems. Non-floating aluminum silver paste is recommended to ensure interlayer bonding strength.
III. Application of Aluminum Silver Paste in Topcoats: Weather Resistance and Decoration
Topcoats are directly exposed to the marine environment and must simultaneously meet requirements for weather resistance, decoration, and stain resistance. The application of aluminum silver paste in topcoats is the most complex:
Weather Resistance Priority: The aluminum silver paste in the topcoat must undergo rigorous weather resistance testing. Fluorocarbon or polyurethane resin systems are recommended. Surface treatment of the aluminum silver paste requires UV-resistant coating technology to prevent chalking or loss of gloss in the strong UV environment of the ocean.
Low Addition Strategy: The addition amount of aluminum silver paste in the topcoat is typically controlled at 5-10% to balance corrosion resistance and decorative effect. Excessive addition will result in an overly metallic coating, affecting aesthetics.
Decorative Design: Floating aluminum silver paste can be used in the topcoat, allowing aluminum flakes to oriented on the coating surface, creating a metallic sheen. However, it should be noted that floating aluminum silver paste may affect recoatability; an appropriate amount of non-floating aluminum silver paste needs to be added to the formulation for balance.
Stain Resistance Optimization: Biofouling in the marine environment is another challenge facing topcoats. Aluminum silver paste can be compounded with antifouling agents such as organotin and organosilicon to reduce biofouling while providing barrier protection.
IV. Key Considerations for the Synergistic Design of Three-Layer Systems
Uniform Aluminum Silver Paste Type: It is recommended to use aluminum silver paste products from the same supplier in the same marine coating system to ensure consistency in surface treatment technology and particle size distribution, avoiding interlayer compatibility issues.
Gradual Dosage Design: Primer (8-15%) → Intermediate Coat (15-25%) → Topcoat (5-10%), forming a gradient distribution of "high in the middle and low at both ends," ensuring both corrosion resistance and workability/decoration.
Matching Application Parameters: The amount of aluminum silver paste added to different coatings affects the rheological properties of the coating. The thinner ratio, spraying pressure, and drying time must be adjusted accordingly to ensure the quality of each coating application.
The differentiated application of aluminum silver paste in marine primers, intermediate coats, and topcoats is essentially a precise matching of the three major functions of "corrosion protection - thickness enhancement - weather resistance." Only by designing targeted formulations based on the functional positioning of each coating can the barrier advantages of aluminum silver paste be fully utilized, providing corrosion protection for ships throughout their entire lifecycle.
We not only offer standardized aluminum silver paste products, but also provide customized surface treatments, particle size distribution optimization, and dispersion stability enhancement technical support based on customers' formulation systems and performance requirements. Anhui Boyan has established long-term cooperative relationships with many well-known domestic marine coating companies, and its products have been successfully applied in various fields such as container ships, tankers, and offshore platforms.
For sample testing, formulation optimization, or technical consultation regarding aluminum silver paste for marine coatings, please contact the Anhui Boyan technical team. We will use our professional product strength and technical services to help your marine coating system achieve superior corrosion resistance and a longer service life.