In advanced materials, chemicals, new energy, coatings, and plastics, powder serves as the fundamental raw material. Ultra-fine powders are essential to everyday coatings and plastic products, as well as power batteries, electronic substrates, and flame-retardant materials.
However, raw powders naturally have built-in limitations. They tend to agglomerate, prefer water over oil, display poor compatibility with resins, and are prone to oxidation and moisture absorption. Using them directly significantly degrades the quality of the final product.
Coating modification provides a tailored outer layer for powder particles through organic or inorganic encapsulation. This process repairs defects, helps the powder fit various applications, and boosts material performance.
How Does Modification Help Non-Metallic Mineral Fillers?
Non-metallic mineral powders—such as 炭酸カルシウム, talc, kaolin, silica powder, quartz powder, and mica—are the most widely used filling and reinforcing powders in industry. They find broad application in plastics, rubber, coatings, and adhesives, representing the category with the highest modification rate.
Naturally hydrophilic with strong surface polarity, these powders conflict with organic hydrophobic systems like plastics, resins, and rubber. When untreated mineral powders are added directly, they cluster severely and disperse unevenly. Instead of providing reinforcement, toughness, or cost reduction, they cause cracking, low gloss, reduced mechanical strength, and processing jams.
After coating modification, the powder surface shifts from hydrophilic to lipophilic. This allows it to blend smoothly into organic matrices, significantly increasing filling capacity, dispersion uniformity, and interfacial bonding. While lowering raw material costs, it enhances hardness, weather resistance, and dimensional stability. Specifically, modified spherical silica fits 5G high-frequency copper-clad laminates by reducing thermal expansion and ensuring stable signal transmission.
Why Must Inorganic Flame-Retardant Powders Be Coated?
Aluminum hydroxide and magnesium hydroxide serve as common eco-friendly, halogen-free flame retardants. They offer flame retardancy, smoke suppression, and non-toxic benefits across wire and cable, flame-retardant plastics, and construction fireproofing.
The main drawback of these powders is the exceptionally high loading required. Formulations often need over 50% content to meet flame-retardant standards. Untreated flame-retardant powders absorb moisture heavily and blend poorly with resins. High loading directly compromises tensile strength, toughness, and impact resistance, making products brittle and difficult to process.
Surface coating modification reduces moisture absorption and optimizes interfacial bonding between the powder and matrix. This preserves flame retardancy and smoke suppression while maintaining mechanical strength and improving processing flow. Consequently, it is an essential process for mass-producing halogen-free flame-retardant materials.
How Can Coating Coating Protect Pigment Powders?
Inorganic color pigment powders—led by titanium dioxide (TiO2) along with iron oxide red, black, and yellow—form the core raw materials for coloring coatings, inks, and plastics.
Uncoated titanium dioxide exhibits clear flaws. Its crystal structure has defects, and its strong photocatalytic activity generates reactive oxygen species under ultraviolet light. These species degrade surrounding resins and organic coatings, leading to chalking, discoloration, cracking, and peeling. Additionally, raw titanium dioxide’s high surface energy causes severe agglomeration, which reduces color uniformity and hiding power.
The standard industry solution applies an inorganic coating of silica or zirconia to act as a protective shield around pigment particles. This coating suppresses photocatalytic degradation, significantly extending the weather resistance and lifespan of coatings and profiles. It also improves dispersion, acid-base resistance, and thermal stability, resulting in more uniform coloring and stronger opacity.
Why Is Coating Crucial for New Energy Battery Powders?
The boom in new energy has made lithium battery cathode and anode powders a focus for modification. Key types include lithium iron phosphate, ternary materials, lithium cobalt oxide, artificial/natural graphite, silicon-based anodes, and lithium titanate.
These powders directly dictate battery capacity, cycle life, safety, and rate performance. Raw battery powders face challenges such as poor conductivity, weak interfacial stability, side reactions with electrolytes, high-temperature decomposition, and pulverization during cycling.
Processes like carbon coating and inorganic coating form a stable protective layer on particle surfaces. This layer boosts electrical conductivity, shields against electrolyte corrosion, inhibits side reactions, and prevents electrode expansion and peeling. As a result, it significantly enhances cycle life, charge-discharge efficiency, and high-temperature safety—making it a core process in manufacturing high-end power batteries.
What Makes Modification Essential for Magnetic Powders?
Soft and hard magnetic powders—such as NdFeB, strontium/barium ferrites, carbonyl iron, iron-silicon-aluminum, and nano-iron oxide—are widely used in permanent magnet devices, electromagnetic shielding, and electronic components.
Mainly made of metals or metal oxides, magnetic powders oxidize and corrode easily when exposed to moisture. Over time, this leads to magnetic decay and reduced performance stability. Poor powder dispersion also results in low density during molding, preventing full magnetic performance.
Coating modification strengthens oxidation and corrosion resistance, stabilizes magnetic properties, and improves dispersion and moldability. It prevents long-term demagnetization and failure, meeting the strict demands of precision electronics and new energy motors.
How Does 表面改質 Fix Carbon and Thermal Powders?
Carbon-based powders—such as graphite, graphene, carbon nanotubes, and carbon fiber powders—along with thermally conductive powders like alumina, aluminum nitride, silicon carbide, and metal powders, form key raw materials for thermal, conductive, and reinforced composites.
These ultra-fine and nano-scale powders agglomerate easily, making uniform dispersion in resins or rubber difficult. Direct use causes localized variations in thermal or electrical conductivity and performance fluctuations. Furthermore, weak bonding between carbon materials and organic matrices often causes delamination and detachment.
Coating modification adjusts surface characteristics to eliminate agglomeration issues while improving compatibility and bonding strength with the matrix. This unlocks the powder’s full thermal, electrical, and reinforcement capabilities, making it valuable for heat dissipation devices, conductive plastics, and advanced composite materials.
How Does Coating Improve Functional Ceramic Powders?
Ceramic powders like alumina, zirconia, aluminum nitride, silicon nitride, and barium titanate are widely used in precision, electronic, and structural ceramics.
Raw ceramic powders feature inconsistent surface activity and poor sintering uniformity. After molding and sintering, products often develop pores, cracks, and insufficient density, which leads to inadequate hardness, insulation, and high-temperature resistance. Coating modification regulates surface activity evenly, optimizes sintering behavior, and raises the density, mechanical strength, and electrical stability of ceramic products.
Summary: Why Are More Powders Requiring Coating Modification?
Simply put, most inorganic, ultra-fine, and functional powders need coating modification. Its primary value is not merely incremental improvement; it fixes inherent powder flaws, unlocks material functionality, stabilizes product quality, and expands application scenarios. From everyday plastics and coatings to new energy, electronics, and advanced materials, powder coating modification has become a critical process that determines product quality and performance.
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