Five methods of surface treatment for common aluminum alloy die castings

2020-11-19 04:30:54

Many technology companies are interested in how the surface of aluminum alloy die castings is smooth and frosted, and how aluminum alloys make such surfaces. Small aluminum alloy is introduced today. Surface treatment method of aluminum alloy die castings.

Method one: Aluminum phosphating

The effects of promoters such as fluorine, Mn2 +, Ni2 +, Zn2 +, PO4 +, Fe2 + on aluminum phosphating process were studied in detail by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Po time curve and film weight change. The results show that guanidine nitrate has the characteristics of good water solubility, low dosage and fast film formation. It is an effective accelerant for aluminum phosphating: fluorine can promote the formation of phosphating film, increase the weight of phosphating film and refine grain; Mn2 +, Ni2 + can obviously refine grain, make phosphating film uniform and dense, improve the appearance of phosphating film; when Zn2 + concentration is low, the film can not be formed or refined, and the film performance is poor. With the increase of Zn2 + concentration, the film weight increases, and PO4 content has a great influence on the phosphating film weight, which makes PO4 increase. This content increases the weight of phosphating film.

Method 2: alkaline electrolytic polishing of aluminum

The alkaline polishing solution system was studied, and the effects of corrosion inhibitor and viscosity agent on polishing effect were compared. The alkaline solution system with good polishing effect was successfully obtained. For the first time, a solution which can not only reduce the working temperature but also prolong the service life of the solution additive is obtained, which improves the polishing effect. The experimental results show that good polishing effect can be obtained by adding proper additives into NaOH solution.

The exploratory experiment also found that under certain conditions, the reflectivity of aluminum surface can reach 90% when glucose sodium hydroxide solution is used for DC constant voltage electrolytic polishing. However, due to the unstable factors in the experiment, further research is needed. The feasibility of DC pulse electrolytic polishing of aluminum under alkaline condition was discussed. The results show that the pulse electropolishing method can achieve the leveling effect of DC constant voltage electrolytic polishing, but the leveling speed is slow.

Method 3: environmentally friendly chemical polishing of aluminum and its alloys

In order to achieve zero emission of NOx and overcome the quality defects of previous similar technologies, a new environmentally friendly chemical polishing technology based on phosphoric acid and sulfuric acid was developed. The key of the new process is to add some compounds with special effect to replace nitric acid. Therefore, we first need to analyze the chemical polishing process of aluminum oxide, especially the role of nitric acid. The main function of nitric acid in aluminum chemical polishing is to inhibit pitting corrosion and improve polishing brightness. Combined with the chemical polishing test of pure phosphoric acid - sulfuric acid, it is considered that adding special materials into phosphoric acid - sulfuric acid can inhibit pitting corrosion and slow down overall corrosion, at the same time, it must have good leveling and bright effect.


Method 4: electrochemical surface strengthening of aluminum and its alloys

The process, properties, morphology, composition and structure of ceramic like amorphous composite conversion film formed by anodic oxidation deposition of aluminum and aluminum alloy in neutral system are discussed. The formation process and mechanism of the films are discussed.

The results show that in the neutral mixture of sodium tungstate and sodium tungstate, the concentration of film-forming promoter is controlled between 2.5-3.0 g / L,

The results showed that the concentration of composite film forming agent was 1.5-3.0 g / L, and the concentration of Na ò 2WO was 1.5-3.0 g / L? 1.5-3.0 g / L? 1.5-3.0 g / L? 1.5-3.0 g / L? 1.5-3.0 g / L? 1.5-3? The peak current density is 6-12a / DM2. The thickness of the coating is 5-10 μ m, the microhardness is 300-540hv, and the corrosion resistance is good. It has good adaptability to various aluminum alloy systems.

Method 5: surface treatment of YL112 aluminum alloy

YL112 aluminum alloy is widely used in automobile, motorcycle and other industries. Surface treatment should be carried out before use to improve the corrosion resistance of the material and form a surface layer easy to combine with organic coating for subsequent surface treatment.


label

0

Recent browsing:

Related products

Related news