Surface treatment refers to the technology and process of processing and modifying the surface of a material to improve its appearance, performance or protection. The surface treatment can be applied to a variety of materials, including metal, plastic, wood and glass. Its main purpose is to improve the corrosion resistance, wear resistance, hardness, conductivity, decoration and adhesion of the material.
Mechanical Treatment
Sandblasting and Shotblasting
As the most common physical polishing method, it is used to remove dirt, oxidation layers, defects, etc.
Sand blasting is used to spray abrasive particles such as sand onto the surface of the workpiece by compressed air or liquid (water), suitable for the treatment of complex shapes of the workpiece and a variety of materials, such as metal, glass, plastic and wood;
Shot blasting uses mechanical or pneumatic equipment to hurl abrasives with high hardness such as steel balls onto the workpiece surface at high speed, which is suitable for rust removal and strengthening of large metal surfaces. Both can effectively remove surface dirt, oxidation layer and blemishes, making the surface more uniform and smooth.
Brush Polish
Metal brushing is a process that uses abrasive materials and chemical corrosion to create a uniform, fingerprint-like texture on the metal surface. This technique gives the metal a satin-like finish, enhancing its appearance and corrosion resistance. It is valued for its decorative appeal and is used to produce various patterns, such as straight, random, threaded, wavy, and spiral textures. More used in stainless steel, aluminum, copper.
Laser Marking and Rust Removal
Laser marking uses high-energy laser beams to create permanent marks on the surfaces of materials such as metal, plastic, glass, ceramics, and wood, widely used in industry and manufacturing. Laser rust removal, on the other hand, uses high-energy laser beams to remove rust layers from metal surfaces like steel, iron, and aluminum, effectively cleaning without damaging the base material.
Laser Rust Removal Laser Marking
Chemical Treatment
Pickling, Phosphating, Passivation and Silane Coating
Pickling, phosphating, passivation, and silane coating are common metal surface treatment processes. Pickling uses acid solutions to remove rust and oxides from metal surfaces, commonly used for steel. Phosphating forms a phosphate layer on the pickled metal surface, enhancing corrosion resistance and coating adhesion, suitable for steel and aluminum. Passivation uses oxidizing agents to create an inert protective film on the metal surface, mainly for stainless steel, improving its corrosion resistance. Silane coating, also known as silane treatment or ceramization, involves applying a silane-based solution to the metal surface, forming a thin ceramic-like layer. This process improves the adhesion of subsequent coatings and enhances corrosion resistance, and is applicable to various metals, including steel, aluminum, and zinc. These processes are often used as pre-processing treatments.
Passivation Tank
Electrophoretic Deposition, EPD
Electrophoretic deposition (also known as electrophoretic coating or electrodeposition) is primarily used to coat metal surfaces to enhance corrosion resistance and aesthetics. The principle involves immersing metal parts in a liquid containing charged paint particles. By applying an electric field, the charged paint particles migrate and deposit uniformly on the metal surface. This process can also be applied to non-metallic materials by coating plastic surfaces with conductive primers or incorporating conductive fillers, enabling electrophoretic coating. The coating thickness achieved with electrophoretic deposition is typically limited, usually within a range of several tens of micrometers.
Surface finish of electrophoretic products
Electroplating
Unlike electrophoresis, which deposits coating molecules on surfaces, electroplating involves depositing a thin layer of metal on the surface of a metal or conductive substrate through an electrochemical reaction. The substrate acts as the cathode and the plating metal as the anode. Under the influence of an electric current, metal ions dissolve from the anode and deposit onto the cathode surface. This process can enhance corrosion resistance, hardness, and wear resistance. It can also increase conductivity or weldability, improve appearance by making it shinier and more attractive, and repair and restore worn or damaged parts.
Typical applications include galvanizing (rust prevention), nickel plating (decoration and wear resistance), gold plating (electrical contacts and decoration), and copper plating (conductivity and decoration) etc.
Dacromet
Dacromet Coating is a new type of anti-corrosion coating process primarily composed of zinc powder, aluminum powder, chromic acid, and deionized water. Through processes like dipping, spinning, and baking, it forms an inorganic coating on the metal surface, consisting of overlapping layers of zinc and aluminum, along with a passivation film formed by chromates. Dacromet offers excellent corrosion resistance, particularly in harsh environments, providing long-lasting protection. Moreover, it is environmentally friendly with minimal pollution during processing, making it a green industrial technology.
Compared to electroplating, Dacromet differs in that it does not rely on electrochemical reactions but instead forms a coating through physical methods, offering superior environmental friendliness. Electroplating uses electric currents to deposit metal ions (such as zinc or chrome) onto the workpiece surface, creating a shiny metal layer, primarily enhancing appearance and hardness. Dacromet’s corrosion resistance significantly exceeds that of electroplating, with performance up to 7-10 times better than zinc plating, while electroplating is often preferred for applications where aesthetics are a key concern.
Bolts Treated by dip
It is normally treated by dip and spin coating of this aqueous solution followed by heat-treatment at a relatively 300°C temperature. As a result, 7-8 μm thick coating is formed by drying and curing during the hot air drying process.
Powder Coating
