What are the surface treatment methods for aluminum alloy materials?

As we all know, aluminum alloy materials have the advantages of light weight, easy processing and various surface treatment methods, and are used in many industries. So what are the surface treatment methods of aluminum alloy materials, and how to choose the surface treatment method is suitable for their own products? Below, I will list and summarize the common surface treatment methods of aluminum alloy materials.

Pretreatment method：

1.polishing：Polishing refers to the processing method of reducing the surface roughness of the workpiece by mechanical, chemical or electrochemical action to obtain a bright and flat surface. It is the modification of the workpiece surface with polishing tools, abrasive particles or other polishing media.

2.Sandblasting：The process of cleaning and roughening the substrate surface by using the impact of high-speed sand flow. Using compressed air as power, To form a high-speed jet beam (copper ore, quartz sand, carborundum, iron sand and Hainan sand) is sprayed to the workpiece surface to be treated at high speed, which changes the appearance or shape of the outer surface of the workpiece surface. Due to the impact and cutting effect of abrasive on the workpiece surface, the workpiece surface obtains certain cleanliness and different roughness, and the mechanical properties of the workpiece surface are improved, so the working efficiency is improved The fatigue resistance of the part increases the adhesion between it and the coating, prolongs the durability of the coating film, and is also conducive to the leveling and decoration of the coating.

3.Wire drawing：Surface wire drawing treatment is a surface treatment method to form lines on the workpiece surface by grinding products and play a decorative effect. Because the surface wire drawing treatment can reflect the texture of metal materials, it has been loved by more and more users and widely used.Wire drawing can also be called sand sweeping, nylon sweeping, etc. It is usually divided into straight wire and tangled wire according to different surface effects. Straight silk is also called hair pattern, and tangled silk is also called snow pattern. The good or bad of silk pattern type is very subjective. Each user has different requirements for surface lines and different preferences for line effects. Some people think the hair looks good, some people like snowflake pattern, some people like long silk, others like short silk. Due to the variety of wire drawing effect, it is usually difficult to describe and specifically define it. Instead, the effect of wire drawing line is determined by determining the processing mode of wire drawing, the grinding products used, process parameters and so on.

4.Embossing：Embossing is a common processing technology of decorative packaging materials. The pressing pattern is divided into plate embossing and roller embossing. Embossing process is a kind of technology that uses molds with concave convex lines to deform pressure bearing materials (PVC, aluminum, wood, paper, etc.) under the action of certain pressure and temperature to form certain patterns, so as to carry out artistic processing on the surface of decorative packaging materials.

Surface treatment method:

1.Anodizing and hard oxidation：Anodic oxidation refers to the electrochemical oxidation of metals or alloys. Aluminum and its alloys form an oxide film on aluminum products (anodes) under the action of external current under corresponding electrolyte and specific process conditions. If there is no special indication, anodic oxidation usually refers to sulfuric acid anodic oxidation.

In order to overcome the defects of surface hardness and wear resistance of aluminum alloy, expand the scope of application and prolong the service life, surface treatment technology has become an indispensable part in the use of aluminum alloy, and anodic oxidation technology is the most widely used and successful.

Anodizing is to use metal or alloy parts as anodes and form oxide films on their surfaces by electrolysis. Metal oxide film changes the surface state and properties, such as surface coloring, improving corrosion resistance, enhancing wear resistance and hardness, protecting metal surface and so on. The film thickness is generally 8um-10um.It can be made in many colors, which is suitable for decorative parts. It is easy to fade when used outdoors.

Hard anodizing is the full name of hard anodizing. The thickness of hard anodic oxide film is generally required to be 25-150um. The thickness of most hard anodic oxide films is 50-80um. The thickness of hard anodic oxide film with film thickness less than 25um is used for parts used in tooth keys, spirals and other occasions. The thickness of anodic oxide film for wear resistance or insulation is about 50um. Under some special process conditions, it is required to produce hard anodic oxide film with thickness of more than 125um, However, it must be noted that the thicker the anodic oxide film, the lower the microhardness of the outer layer and the increase of the surface roughness of the film.

It is not only suitable for deformed aluminum alloy, but also for die-casting aluminum alloy parts.Color is the color of electrolytic thickness of materials. According to different materials, the colors are dark coffee, gray, brown and black. They can not be dyed and can be used outside the room. It is generally used in the environment without appearance requirements requiring wear resistance and salt fog resistance.

2.Fluorocarbon baking paint: fluorocarbon baking paint is a super durable baking fluorocarbon paint, with fluororesin as the main component. Fluorocarbon baking paint is specially designed for the baking paint production line of spraying plant, with excellent durability, protection, lasting beauty and other excellent properties.

Fluorocarbon baking paint has super durability, super weather resistance, anti-corrosion and strong self-cleaning; Strong adhesion, high decoration, water and enzyme resistance, acid and alkali resistance; Good film performance: fast drying, flexibility, scratch resistance and washability; High transparency, high hardness, high fullness, non yellowing and other product features.

Fluorocarbon baking paint can be used for the durability decorative protective coating of various aluminum curtain wallboards, aluminum profiles and other metal materials, as well as the durability protective coating of steel structure equipment.

Fluorocarbon baking paint is flammable and should be stored in a cool place to avoid sun and rain, away from heat source and pay attention to fire safety.

3.Electrostatic powder spraying: electrostatic powder spraying is commonly known as "electrostatic plastic spraying". Main features: the spraying method can be manual, automatic or manual + automatic. The spraying material is 100% solid powder, the free powder can be recycled, and the recycling rate of coating can reach 98%. Suspension transportation system, high degree of automation. The coating has few micropores and good anti-corrosion performance, and can be sprayed with thick film at one time. As long as the powder coating is directly sprayed on the surface of the pretreated MDF plate and baked, the coating surface with excellent performance can be obtained. General powder coatings have long-lasting properties, including wear resistance, impact resistance, adhesion, toughness, corrosion resistance and chemical resistance. In addition to the above advantages, powder coatings for outdoor use also include high weather resistance and pollution resistance. High thickness coating can be obtained by one-time spraying of powder coating, and the film thickness can be 50-300 μ M, and there is no drop or accumulation of solvent coating during thick coating.

4.Electrophoresis，EP: electrophoresis, also known as electrocution (by), swimming paint, electrodeposition. It was first applied to automobile primer by Ford Motor Company in the 1960s. Due to its excellent anti-corrosion and anti rust functions, it has been widely used in the military industry. It has only been applied to the surface treatment of daily hardware in recent years. Due to its excellent quality and high environmental protection, it is gradually replacing the traditional paint spraying. Electrophoretic paint film : electrophoretic paint film has the advantages of plump, uniform, flat and smooth coating. The hardness, adhesion, corrosion resistance, impact performance and permeability of electrophoretic paint film are obviously better than those of other coating processes. Detailed features: (1) water soluble coating is adopted, with water as the dissolution medium, which saves a lot of organic solvents, greatly reduces air pollution and environmental hazards, safety and health, and avoids the hidden danger of fire; (2) high coating efficiency, small coating loss, and the utilization rate of coating can reach 90% ~ 95%; (3) The coating film has uniform thickness, strong adhesion and good coating quality. Uniform and smooth paint film can be obtained at all parts of the workpiece, such as inner layer, depression and weld, which solves the coating problems of complex shape workpieces by other coating methods; (4) high production efficiency, automatic continuous production can be realized in construction, and labor efficiency can be greatly improved; (5) The equipment is complex, the investment cost is high, the power consumption is large, the drying and curing temperature is high, the management of coating and coating is complex, the construction conditions are strict, and wastewater treatment is required; (6) only water-soluble coatings can be used, the color cannot be changed in the coating process, and the stability of the coatings is difficult to control if they are stored for too long. (7) Electrophoretic coating equipment is complex with high scientific and technological content, which is suitable for the production of fixed color.

5.Electroplating: electroplating is the process of plating a thin layer of other metals or alloys on the surface of some metals by using the principle of electrolysis, It is a process of using electrolysis to attach a layer of metal film to the surface of metal or other material parts, so as to prevent metal oxidation (such as corrosion), improve wear resistance, conductivity, reflection, corrosion resistance (copper sulfate, etc.) and enhance beauty. The outer layer of many coins is also electroplated.