News

Pretreatment process and method of aluminum alloy

Release time:

2022-08-09 09:56

 

Degreasing Process and Method of Aluminum Alloy

1

The chemical activity of metal aluminum is very high. It is quickly oxidized in the air to generate a layer of natural oxide layer. This layer of natural oxide layer has a certain protective effect on aluminum, but if you want to do passivation treatment or coating (painting, powder spraying) treatment, the oxide layer must be removed first to ensure the uniformity and integrity of the passivation film.

2

Aluminum alloy chemical degreasing can be used in alkaline degreasing and acidic degreasing, but also through sandblasting or rolling treatment to achieve the purpose of degreasing and descaling.

3

Alkaline degreasing of aluminum alloy generally uses M-265 weak alkaline alloy degreasing agent. Strong alkaline degreasing will cause corrosion, blackening and ash hanging on aluminum alloy. Alkaline degreasing cannot remove the oxide layer on the surface of aluminum alloy. If alkaline degreasing is used, the surface oxide layer needs to be removed through acid activation (also known as surface adjustment, light emission and neutralization) before passivation in the post-process, otherwise a complete passivation film cannot be formed, the absence of a complete passivation film has a significant impact on coating adhesion and salt spray testing.

4

Aluminum alloy can also use acidic degreasing, through the M-267 of acidic degreasing agent to complete, can achieve the effect of degreasing and descaling. The choice of aluminum acid degreasing agent should distinguish between aluminum profile and cast aluminum. Different materials and formulas will be different. Cast aluminum is easy to be discolored, blackened or gray.

5

In the casting process of cast aluminum workpiece, a small amount of mold release agent should be added to the mold, and paraffin wax will be contained in the low-grade remover. Therefore, in addition to general oil stains, there may also be waxy oil stains on the surface of cast aluminum workpiece. At this time, only ordinary alkaline oil removal or acid oil removal cannot be cleaned.

6

in addition to the preparation of oil liquid method:

Method 1: Degreasing Powder + Degreasing Agent (4-5% each)-Two-component

Method 2: Oil removal additive + oil removal agent (4-5% each)-two-component

Method 3: single component degreasing powder (use ratio 4-6%)-single component

Method 4: Single-component degreaser (6-8%)-Single-component

Method 5: aluminum acid degreasing agent (use ratio 5-6%)-single component

 

Passivation treatment process and method of aluminum alloy

1

Passivation process type

◆ Hexavalent chromium passivation: can generate colorless transparent passivation film or golden yellow passivation film

◆ Trivalent chromium passivation: passivation film color will change with different aluminum alloy materials, from colorless-light blue-gray-color passivation film

◆ Aluminum chromium-free passivation agent: it can generate colorless transparent passivation film or color passivation film, and it will also change the appearance color of passivation film with different aluminum alloy materials and models.

2

Description of the use of different passivation processes

(1) hexavalent chromium, trivalent chromium, chromium-free passivation can be used for paint, powder pretreatment passivation.

(2) The bare film after hexavalent chromium passivation and trivalent chromium passivation can be directly used as the final anti-corrosion layer; the corrosion resistance of the bare film of aluminum chromium-free passivation film is not as good as that of hexavalent or trivalent chromium passivation, and is more used for pre-coating treatment.

(3) Comparison of salt spray test time

A, trivalent chromium and hexavalent chromium passivation film:

The salt spray test time for bare film of aluminum plate/aluminum profile can reach 100 hours, and the salt spray test time for coating after coating can reach 1000 hours. Cast aluminum may be reduced to a certain extent due to different aluminum ingot types and impurity contents.

B, aluminum chromium-free passivator:

The salt spray test time for bare film of aluminum plate/aluminum profile can reach 72 hours, and the salt spray test time for coating after coating can reach 1000 hours. Cast aluminum may be reduced to a certain extent due to different aluminum ingot types and impurity contents.

C. The salt spray resistance time of the coating after coating is also related to the quality of the coating and the thickness of the coating. The coating thickness requirements are: more than 60um for powder coating and more than 20um for paint coating.

D, salt spray test conditions: 5% sodium chloride neutral salt spray, 35 ℃

 

 

Process, passivation, aluminum alloy, coating, method, oxidation, treatment, alkaline, acidic, test

Previous

Analysis of Dust Hanging Problem of Galvanized Sheet Ceramic

Classification and process control of aluminum chromizing process

Next

Previous

Analysis of Dust Hanging Problem of Galvanized Sheet Ceramic

Next

Classification and process control of aluminum chromizing process

Other News

The main advantages of phosphating agent using spray method

2023-05-04

The role of phosphating agent is obvious to all. It can not only bring rich benefits to modern machinery production, but also make new breakthroughs in improving the overall processing quality. With the continuous introduction of technology, the type of phosphating solution has also undergone many changes. Medium temperature phosphating solution, slag-free phosphating solution and galvanizing phosphating solution are all representatives of technological innovation. In order to give full play to its use value, manufacturers need to improve the operability of the spraying method, then, the following together to understand the main advantages of phosphating agent using spray method! On the one hand, manufacturers in the use of phosphating agent, comparative analysis of applicable methods. If the phosphating agent is sprayed directly on the surface of the workpiece, the formation speed of the phosphating film is much faster than that of the workpiece immersed in the same phosphating solution, or the phosphating can be carried out at the same time at a lower temperature. In the iron-containing phosphating solution, the iron ions will be oxidized by the atmosphere during the spraying phosphating process, so the spraying phosphating method cannot be used for iron salt phosphating. The spraying method is also not suitable for high-temperature manganese salt phosphating because the heat loss is too large. On the other hand, the spraying method is a method accepted by many manufacturers. The advantages are as follows: 1. The phosphating solution in contact with the metal surface is always fresh. Soaking methods are different. The phosphating solution in contact with the metal surface will gradually lack the film-forming ions, which can only be formed by the diffusion of the phosphating solution from a distance.

The Difference of Phosphating Agent

2023-04-12

Now a lot of phosphating agent, so we are not unfamiliar with phosphating agent, but we know the difference between good phosphating agent and poor quality phosphating agent. However, good phosphating agents are quite different. Good phosphating agent has more advantages in use effect and cost, so, let's understand the difference between the advantages and disadvantages of phosphating agent together! 1. The coating speed is fast. Compared with inferior surface adjustment, good surface adjustment can completely coat the film in a short time, especially on the spraying line. Its advantages are inferior surface adjustment can not be compared. 2, good anti-rust performance, due to the high quality surface conditioning gel peptide particles have reached the nanometer level, high activity, the resulting phosphating nucleus is extremely fine, so it has a strong anti-rust performance. 3. Cost saving and good surface adjustment quality. Due to the dense phosphating film, it will not produce secondary crystallization. In the case of good anti-rust performance, the amount of phosphating solution can be reduced. According to the analysis of experimental data and the actual use of customers can save 10% of the phosphating solution. Because the phosphating film is thin and dense, it is also a big advantage for saving paint. Compared with powder spraying, due to the thicker coating and the operating habits of spraying personnel,

Analysis on the Development Potential of Phosphating Agent Industry

2023-03-20

Phosphating agent technology has been developed for more than 100 years. For more than 100 years, phosphating technology has developed from a simple chemical corrosion method to a complex and comprehensive technology. The application scope of phosphating treatment technology has also developed from the initial metal anti-corrosion to today's metal coating pre-phosphating treatment, metal wear-resistant phosphating treatment, metal anti-corrosion phosphating treatment and metal plasticizing treatment. Phosphating treatment and other applications before denaturation processing, then, let's understand the development potential analysis of phosphating agent industry together! Statistics show that China's phosphate rock reserves account for 5.7 of the world's total, ranking second in the world, with an average grade of about 17%, of which intermediate phosphate rock (grade above 30%) accounts for only 16.7, while the price of phosphate rock in India is 210 US dollars/ton (68-70% BPL), equivalent to the domestic price of 1432 yuan/ton, which is about 1.5 times higher than the price in Hubei market. "China's phosphate rock 'many but not rich', high-grade phosphate rock is very scarce, the price difference at home and abroad is huge." Analysis of the development potential of the phosphating agent industry Phosphating agent refers to the chemical sub-industry that uses phosphate rock as raw material and processes the phosphorus element in the ore into products through chemical methods. The main products are yellow phosphorus, phosphate fertilizer, phosphoric acid, phosphate fertilizer, etc., which are widely used in daily chemicals, food, electronics, medicine, pesticides,

What are the problems of phosphating agent?

2023-02-08

What are the problems of phosphating agent? The role of phosphating agent is mainly in two aspects: on the one hand, the phosphating agent plays the role of cathodic depolarization in the process of forming chemical conversion film, which promotes the normal progress of electrochemical conversion reaction, so as to ensure the normal progress of chemical deposition reaction, that is, the formation of chemical conversion layer. On the other hand, these accelerators are mostly oxidizing species. During the chemical conversion treatment, the ferrous ions dissolved in the iron-containing metal material treatment solution are oxidized to ferric ions, thereby preventing the enrichment of the ferric ions during the chemical conversion, preventing the aging of the chemical treatment solution due to the enrichment of the ferrous ions, and preventing the possibility of a good conversion layer. However, each of the regular chemical conversion phosphating agents has various problems to be solved. A wide range of sulfites are not stable in acid solutions and must be added continuously as an ingredient during use to replenish the amount of sulfite equivalent to consumption, thereby keeping the concentration of nitrous salt constant. More importantly, a part of the phosphite is converted into NOx gas during the oxidation or natural decomposition reaction, and the obtained NOx gas is diffused into the atmosphere and causes pollution. Chlorate alone is less effective when used as a chemical conversion phosphating agent. It is usually chemically transformed with another

What is phosphating agent?

2023-01-10

What is the phosphating agent? Phosphating is a commonly used pretreatment technology. In principle, it belongs to chemical conversion surface treatment, which is mainly used in the phosphating of steel surface. Non-ferrous metals (such as aluminum and zinc) can also be used for phosphating. Phosphating is the process of chemical and electrochemical reaction of phosphate chemical conversion surface, called phosphating surface. The purpose of phosphating is mainly to provide protection for the base metal and prevent metal corrosion to a certain extent; it is used as a primer before painting to improve the adhesion and corrosion resistance of the paint surface; it plays a role in the cold working of the metal. Anti-friction and lubrication. The principle of the phosphating agent is that the chemical liquid itself reacts with the substrate, and a void-free chemical conversion surface layer appears on the surface of the substrate to protect the substrate. Phosphating agent is a kind of chemical widely used in the pretreatment of professional spraying plants. It can provide temporary rust prevention and good adhesive layer of paint and powder for spraying workpieces. Classification: Iron phosphating agent It is a light blue acidic coating that can appear on the surface of steel, zinc and aluminum with a thickness of 0.8-1.7 μm. It is the surface of yellow, red and blue. It has good compatibility with electrophoretic coating and powder coating, making the thin surface layer resistant to bending, deformation and strong resistance. The single-liquid product has stable performance, almost no precipitation, convenient tank management, and elimination.

What are the ingredients of different phosphating agents?

2022-12-30

Iron phosphating agent It is a light blue acidic coating that can form a thickness of 0.8-1.7 μm on the surface of steel, zinc and aluminum. It is a film of yellow, red and blue. It has good compatibility with electrophoretic coating and powder coating, making the film resistant to bending, deformation and strong resistance. The product is a single liquid, stable performance, almost no sediment, easy to tank liquid management, low cost, wide processing temperature. Zinc phosphating agent can form a gray, uniform and dense phosphate film on the surface of steel and zinc at room temperature. It can be used as a primer for paint and can enhance the adhesion and rust resistance of the paint. The product has a wide process range, and the film is formed quickly and uniformly. Each kilogram of concentrated solution can process the surface of the workpiece 30-40m. Low temperature phosphating solution is suitable for surface treatment of steel products. A dense phosphating film can be formed in a short time. The phosphating film has strong anti-rust ability and can significantly improve the adhesion between the substrate and the coating. The big advantage is that the plating solution is extremely stable, the phosphating time is short, the processing temperature is low, no heating equipment is required, the phosphating film is fine and uniform, the operating process is wide, and the deposit is small. It is an environmentally friendly phosphating solution. Galvanized plate phosphating solution is suitable for the phosphating treatment of galvanized plate products, as well as plating.

COOKIES

Our website uses cookies and similar technologies to personalize the advertising shown to you and to help you get the best experience on our website. For more information, see our Privacy & Cookie Policy

COOKIES

Our website uses cookies and similar technologies to personalize the advertising shown to you and to help you get the best experience on our website. For more information, see our Privacy & Cookie Policy

These cookies are necessary for basic functions such as payment. Standard cookies cannot be turned off and do not store any of your information.

These cookies collect information, such as how many people are using our site or which pages are popular, to help us improve the customer experience. Turning these cookies off will mean we can't collect information to improve your experience.

These cookies enable the website to provide enhanced functionality and personalization. They may be set by us or by third-party providers whose services we have added to our pages. If you do not allow these cookies, some or all of these services may not function properly.

These cookies help us understand what you are interested in so that we can show you relevant advertising on other websites. Turning these cookies off will mean we are unable to show you any personalized advertising.

Copyright Foshan Shunde Meisoon Metal Surface Technology Co,.Ltd. Website Construction:China Enterprise Power   Shunde SEO

Business License