Surface Treatment: Working Principle And Application of Electroplating Technology

Electroplating stands as a prominent technique in precision engineering, elevating both the look and functionality of parts. While traditionally confined to metals, recent technological strides have broadened its scope to encompass non-metallic substances. Electroplating now offers a versatile fusion of desirable attributes, including enhanced strength, wear resistance, aesthetic appeal, corrosion protection, and conductivity.

What is Electroplating?

Electroplating serves as a surface engineering method, depositing a thin layer of metal or alloy onto specific metals via electrochemical processes. This procedure aims to combat metal oxidation, boost wear resistance, conductivity, reflectivity, corrosion resistance, and refine aesthetics.

To execute electroplating, a low-voltage, high-current power source is essential, feeding the plating bath and electrolytic setup. The plating solution comprises various elements, including metal salts, complexing agents, buffering agents, and additives like brighteners and wetting agents. During the electroplating process, metal ions from the solution migrate to the cathode (workpiece) under the influence of electric current, where they undergo reduction and form a metal layer. Meanwhile, metal from the anode dissolves into the solution, ensuring a steady concentration of metal ions.

Stages of the Electroplating Process:

Hanging:Secure the components onto a conductive tool to establish a closed circuit with the power source, facilitating the electroplating process.

Degreasing:Thoroughly clean the component surface to eliminate oil, dust, and sweat stains, ensuring optimal electroplating results and surface appearance.

Roughening:Utilize a roughening solution with potent acidic properties to dissolve specific plastic components on the surface, creating microscopic pores and enhancing the contact area for electroplating while rendering the surface hydrophilic.

Neutralization:Employ the solution's reducing properties to effectively neutralize and eliminate any remaining passivation on the component surface, crucial for ensuring optimal subsequent processes.

Catalysis:Evenly adsorb colloidal palladium into the pores on the component's surface, establishing catalytic centers essential for the subsequent chemical nickel reaction.

Palladium Activation:Activate initially inert colloidal palladium on the component surface by dissolving surrounding divalent tin ions, exposing the catalytic palladium for enhanced functionality.

Chemical Nickel Plating:While the precise mechanism remains incompletely understood, chemical nickel plating relies on a catalyst for its process.

Nickel Undercoat:To address the thinness and poor conductivity of chemical nickel layers (0.2μm), a nickel undercoat is applied to enhance component conductivity.

Bright Copper:Known for its ductility, flexibility, and thermal expansion coefficient akin to plastic, a smooth and flexible copper layer (15-25μm) is applied to improve adhesion between components and the plating layer, offering a buffer against temperature variations and external impacts.

Semi-Bright Nickel:This plating layer provides components with a semi-bright finish, boasting good ductility, leveling properties, low sulfur content (<0.005%), and a brighter appearance compared to bright nickel plating. It offers both mechanical strength and corrosion resistance.

Pearl Nickel:This provides components with a pearl-like bright effect, lending them an elegant and soft color.

Nickel Sealing (Micro-porous Nickel):Fine non-conductive particles (approximately 0.5μm in diameter) are introduced into the electroplating solution. These particles integrate into the plating layer, creating micro-pores that enhance corrosion resistance by dispersing corrosion current and reducing corrosion rates.

Bright Passivation:Resulting in a dazzling silver-white appearance, this process enhances the decorative effect of components.

Unhanging:Components are removed from fixtures for inspection and packaging.

The electroplating process varies depending on specific requirements and materials involved. Each step requires meticulous control to ensure quality and performance, considering factors like electrolyte composition, temperature, current density, and plating time.

Types of electroplating

Electroplating processes are categorized by coating composition, encompassing chrome, copper, nickel, tin, zinc plating, and more. Moreover, electroplating serves distinct purposes, including protective, decorative, and functional applications. Protective electroplating shields against oxidation and corrosion, while decorative electroplating enhances product aesthetics. Functional electroplating modifies properties such as hardness and wear resistance.

Electroplating varies according to the electroplating solution, with classifications like cyanide plating, sulfate plating, pyrophosphate plating, and others. Additionally, it can be categorized based on the plating layer's characteristics, such as hard chromium plating and milky chromium plating. Furthermore, electroplating treatments include chemical plating, composite plating, non-metal plating, gold plating, silver plating, among others.

How to Evaluate the Cost of Electroplating

Determining the weight of the coating involves calculating its volume by multiplying the area and thickness of the coating, followed by multiplying the volume by the density of the coating material. After obtaining the weight, the material cost can be calculated by multiplying the weight of the coating by the unit price of the material.

Applications of Electroplating Technology

In the automotive industry, electroplating technology plays a significant role by enhancing the appearance and performance of various components. This technology provides high gloss, corrosion resistance, and wear resistance, making automotive parts such as wheels, door handles, and front grilles more aesthetically pleasing and durable.

In the electronics industry, electroplating technology holds significant importance, contributing to the enhancement of both appearance and performance of electronic products. By offering attributes like high gloss, corrosion resistance, and wear resistance, electroplating renders products such as mobile phone casings, computer buttons, and flat-screen TV interfaces more appealing and long-lasting.

The aerospace industry heavily relies on electroplating technology due to its demand for exceptional precision, a requirement that electroplating processes can fulfill effectively. Moreover, in communications and military sectors, electroplating serves vital purposes by providing a corrosion-resistant protective layer, thereby prolonging the lifespan of equipment.

Summary

Electroplating, a well-established technology, has long been instrumental in enhancing the performance, durability, and visual appeal of manufactured parts. Successful electroplating necessitates key components like anodes, cathodes, electrolytes, and a power source. Leveraging our expertise, ZONZE stands ready to support diverse manufacturing processes, ensuring the production of top-notch technical products.