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How can a matte and glossy effect be achieved on the surface of aluminum alloy?

Aluminum alloy is widely used in industry and daily life due to its lightweight and high-strength characteristics. After more than 100 years of development, its smelting and purification processes have become mature. Its core advantages lie in low density, high specific strength, good processing performance, strong corrosion resistance, and recyclability. The types of materials have been applied in various industries, such as

The application of lightweight materials and high-strength aluminum alloys,

Key load-bearing structures such as aircraft bodies and wings, transportation, battery trays for new energy vehicles, body frames, chassis components, high-speed rail bodies for rail transit, ship hulls, submarine structures, building curtain walls, electronic radiators, chemical corrosion-resistant equipment, packaging materials, lighting fixtures, decoration materials, electronic equipment casings, etc,

With the widespread application of materials, engineers have developed various surface states based on material characteristics to meet our needs. Currently, we introduce two methods for implementing these surface states.

Implementation method of matte effect:

1. Alkali corrosion treatment uses alkaline solutions such as sodium hydroxide and sodium nitrate to corrode the surface of aluminum alloys. By controlling the concentration, temperature, and treatment time of the solution, uniform micro pits are formed on the aluminum surface, resulting in a matte effect. This method can effectively remove surface scratches and squeeze marks, giving the surface a delicate matte texture.  

2. Acid etching treatment

Acid corrosion of aluminum alloys is mainly carried out using acidic solutions such as ammonium hydrogen fluoride and ammonium fluoride. During the acid etching process, fluoride ions react with the surface of aluminum to form a hazy and fine sand surface effect. By adding corrosion inhibitors, leveling agents, and other additives, the corrosion rate and surface smoothness can be controlled to achieve different thicknesses of matte effect.

3. Sandblasting treatment uses compressed air to rapidly spray abrasives such as quartz sand and steel sand onto the surface of aluminum alloy. Through the impact of the abrasives, a uniform rough texture is formed on the surface, thereby achieving a matte effect. Sandblasting parameters, such as abrasive particle size and spray pressure, can adjust the fineness and roughness of the matte surface.

4. Wire drawing processing is used to create straight, irregular, and wavy lines on the surface of aluminum alloy through mechanical friction. The brushed surface has a matte effect with a fine hair like luster, retaining the metallic texture and presenting a soft visual effect like a matte finish.

Method for achieving bright surface effect:

1. Chemical polishing

Chemical polishing of aluminum alloys using acidic mixed solutions such as phosphoric acid, sulfuric acid, nitric acid, etc. Under high temperature conditions, the convex parts on the aluminum surface dissolve faster, while the concave parts are protected by acidic ions and dissolve slower. After repeated dissolution passivation processes, a highly reflective mirror effect is finally formed.  

2. Electrolytic polishing

Aluminum alloy is used as the anode, placed in electrolytes such as phosphoric acid, sulfuric acid, and chromic acid, and subjected to direct current for electrolysis. During the electrolysis process, the protruding parts on the aluminum surface dissolve first, while the recessed parts dissolve relatively slowly. At the same time, passivating agents (such as chromic acid) in the electrolyte can suppress excessive corrosion, ultimately achieving a mirror like high brightness.  

3. Mechanical polishing

Using polishing wheels, polishing cloths, and other tools, combined with micro abrasive and grease polishing agents, the surface of aluminum alloy is ground and polished. Through multiple processes (rough polishing, medium polishing, and fine polishing), the surface roughness is gradually reduced to achieve a shiny and smooth effect, which can approach the glossiness of stainless steel mirror.   

4. High gloss cutting

Using high-speed rotating cutting tools (such as diamond knives) of precision carving machines, local cutting is carried out on the surface of aluminum alloys to form bright edges or lines. By controlling the tool speed and cutting depth, different brightness bright surface effects can be obtained, commonly used for high gloss treatment of products such as mobile phone frames and metal decorative parts