What is electroplating?

die casting parts deburring

Electroplating is applying a thin layer of other metals or alloys to the surface of certain metals using the principle of electrolysis. It is a process of applying a metal film to the surface of metals or other materials to prevent oxidation (such as rust), improve wear resistance, electrical conductivity, reflectivity, corrosion resistance (copper sulfate, etc.), and improve aesthetics.

What are the main uses of electroplating?

1.To improve the corrosion resistance of metal products or parts. For example, it galvanizes the surface of steel products or parts.

2.To improve the protective and decorative properties of metal products. For example, copper plating, nickel, and chromium plating on the surface of steel products.

3.Repair the size of metal parts. For example, shafts, gears, and other important mechanical parts, after use wear, can use iron plating, chrome plating, and other woes of its size.

Die-casting aluminum alloy plating four kinds of surface treatment methods

● Aluminum phosphating
By using SEM, XRD, potential a time curve, film weight changes, and other methods to study in detail the promoter, fluoride, Mn2+, Ni2+, Zn2+, PO4, and Fe2+, etc., on the phosphating process of aluminum. Research shows that: guanidine nitrate has good water solubility, low dosage, rapid film characteristics, and is an effective promoter of aluminum phosphating: fluoride can promote the film, increase film weight, refining grain; Mn2+ and Ni2+ can significantly refine the grain, so that the phosphate film uniform, dense and can improve the appearance of phosphate film; Zn2+ concentration is low, can not be film or poor film, with Zn2+ concentration increases, the film weight increases O4 content of phosphate film weight, improve the PO4. Content to increase the phosphate film weight.
● Alkaline electrolytic polishing process of aluminum
The study of an alkaline polishing solution system was carried out, comparing the effect of corrosion inhibitors, viscosity agents, etc., on the polishing effect, and successfully obtained an alkaline solution system with a good polishing effect for zinc and aluminum die-cast parts and for the first time obtained additives that can reduce the operating temperature, extend the service life of the solution, and also improve the polishing effect. The experimental results show that adding appropriate additives in NaOH solution can produce a good polishing effect. Exploratory experiments also found that aluminum’s surface reflectivity can reach 90% after DC constant pressure electrolytic polishing with NaOH solution of glucose under certain conditions, but further research is needed because the experiment is still unstable. The feasibility of using the DC pulse electrolytic polishing method to polish aluminum under alkaline conditions was explored, and the results showed that: The leveling effect of DC constant pressure electrolytic polishing can be achieved by using the pulse electrolytic polishing method, but its leveling speed is slow.
● Environmentally friendly chemical polishing of aluminum and aluminum alloy
The development of a new environmentally friendly chemical polishing technology with phosphoric acid and sulfuric acid as the base solution was determined, which should achieve zero NOx emission and overcome the quality defects of similar technologies in the past. The key to the new technology is to add some compounds with special effects to the base solution to replace nitric acid. For this purpose, it is first necessary to analyze the triachemical polishing process of aluminum, with a special focus on the role of nitric acid. The main role of nitric acid in the chemical polishing of aluminum is to inhibit pitting corrosion and improve the brightness of polishing. Combined with the chemical polishing test in simple phosphoric acid sulfuric acid, the special substances added in phosphoric acid sulfuric acid should be able to inhibit pitting corrosion, slow down the overall corrosion, and simultaneously must have a good leveling and brightness effect.

Electrochemical surface strengthening of aluminum and its alloys
The process, properties, morphology, composition, and structure of ceramic-like amorphous composite conversion films deposited by anodic oxidation of aluminum and its alloys in a neutral system were initially investigated, as well as the film formation process and mechanism of the films. The results of the process study showed that in the neutral mixed system of Na_2WO_4, the film-forming accelerator concentration was controlled to be 2.5-3.0 g/l, the complexing film-forming agent concentration was 1.5-3.0 g/l, the Na_2WO_4 concentration was 0.5-0.8 g/l, the peak current density was 6-12 A/dm~2, and weak stirring, and a complete and uniform gray series of the inorganic non-metallic film layer. The thickness of this film layer is 5~10μm; microhardness is 300~540HV and excellent corrosion resistance. The neutral system has good adaptability to aluminum alloys, and the film can be well formed on many series of aluminum alloys, such as rust-proof aluminum and wrought aluminum.

Description of the plating process for die casting

(1) plating use or minimize the polishing process, to reduce the polishing workload, preferably glossy coating.

On the one hand, polishing is not easy due to the complex shape, but on the other hand, the thickness of the coating can be guaranteed to ensure quality.

(2) If the die-casting process is not suitable, or due to improper design of the die-casting mold, if the die-casting surface is cold-rolled, shrinkage hole, loose or pinhole, etc., even if you take measures of the plating process, usually, you can’t get the satisfactory coating.

(3) The shape of die casting is generally complex, and plating requires a solution with excellent dispersion and coating properties.

To prevent the positive metal from being replaced by aluminum in the recess or mask and to prevent good coupling, the pre-plating layer must be selected with a plating solution with good dispersion and coating.


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What is electroplating?

Electroplating is applying a thin layer of other metals or alloys to the surface of certain metals using the principle of electrolysis. It is a

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