Tag Electroplating process

In mechanical design, electroplating is our most common part surface treatment process. In a few days, let’s take a look at 5 commonly used electroplating processes.

Wet Plating:

Wet electroplating is a method that uses electrolysis and chemical reactions to place objects in liquid for electroplating, mainly including electroplating (electrochemical plating) and electroless plating.

Electroplating (electrochemical plating):

A method of immersing metal ions in a solution containing the metal ions to be plated and depositing the metal ions on the metal surface by direct current electrolysis.

The performance indicators of the electroplating layer include appearance, thickness, porosity, corrosion resistance, hardness and internal stress. The appearance is determined by the degree of finishing of the parts to be plated and the conditions of the plating. Thickness depends on “current intensity x electrolysis time”, and hardness and internal stress vary depending on additives and plating conditions.

Therefore, the composition and working conditions of the electroplating tank will affect the quality of the electroplated layer. Also, since electroplating uses hazardous chemicals, great care must be taken when disposing of it, and the wastewater has strict treatment standards depending on the aqueous solution.

In ordinary electroplating, when the plating layer becomes thicker, the luster will disappear. Therefore, by adding suitable additives to the solution, smooth glossy plating can be performed.

In addition, chrome plating is one of the most commonly used electroplating, because the coating has gloss, no discoloration in the air, small friction coefficient, good wear resistance, and good corrosion resistance.

Zinc and cadmium plating, etc. will change color after processing, but by chromate treatment, the corrosion resistance is greatly improved, and glossy or colored films can be obtained.

Electroless plating (electroless plating):

Electroless plating refers to the deposition of metal ions on the surface of other materials by reacting the reducing substances and metal ions of the electroplating solution without using electric energy.

The advantage of this method is that it produces relatively uniform films regardless of the shape of the material. But the precipitation rate is slow, the plating layer is relatively thin, it is difficult to manage equipment materials and solutions, and it is expensive.

In electroless plating, the thickness is uniform, and the hardness can be increased by heating, so it can be used as a wear-resistant film. In addition, electroless copper plating is often used in the pretreatment of electroplating on plastics.

Dry Plating:

Dry plating includes vacuum plating, vapor phase plating (vapor phase deposition), and fusion plating using molten metal.

Vacuum plating:

Vacuum plating is a method of heating and evaporating metals or compounds in a high vacuum to form a thin film of metals or compounds on the surface by applying evaporated atoms or molecules to the object to be plated. Here, a thin film refers to a thin film having a thickness of less than 1 μ.

Industrial applications include decoration, wrapping paper, etc., depositing aluminum on metallic luster, and as electrical applications, for resistors and capacitors.

If the foundation does not outgas, it can use non-metals, not just metals.

In addition, the deposition methods of vacuum plating include PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition). PVD uses heat and plasma energy to vaporize solid material and deposit it on a substrate. CVD is a gas that uses energy such as heat and plasma, including thin films and elements, to adsorb and form thin films on the substrate surface through excitation and decomposition.

In addition, PVD methods also employ methods such as vacuum deposition, sputtering, and ion plating. CVD methods include plasma CVD and thermal CVD. Since there are various thin film forming methods, it is necessary to select after considering the characteristics and application of each thin film.

Vapor phase plating:

The method of obtaining metal coatings by thermal decomposition or hydrogen reduction of metal halides and carbon-based compounds is called “vapor phase plating”. However, it is only suitable for special fields because of the complex and costly equipment, high operating temperature, heating of materials, and presence of hazardous chemicals.

Fusion Plating:

This is a method in which the object to be plated is dipped in a bath of molten metal and pulled up to obtain a film of that metal on the surface. When using this method, fewer types of metals and alloys can be used because the melting point of the material must be higher than that of the metal to be plated. The electroplating operation itself is simple, and a thick electroplating layer can be obtained in a short time, but its thickness cannot be freely controlled.

The electroplating operation itself is very simple, and a thicker electroplating layer can be obtained in a short time, but its thickness cannot be freely controlled. In addition, a part of the material may deteriorate.