Electroless Nickel Immersion Gold Plating

Known for its corrosion resistance and uniform plating deposit, electroless nickel immersion gold (ENIG) is a type of plating commonly used for printed circuit boards. Electroless nickel immersion gold plating consists of a layer of gold over a layer of nickel. The top layer protects the bottom layer from oxidation, ensuring stability.

Like regular electroless nickel, this plating type does not require an external power source to deposit the metallic coating on the base material. ENIG is applied through a chemical reaction.

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Plating Capabilities and Methods

At Sharretts Plating Company, we provide electroless nickel immersion gold plating services to businesses across a range of industries. Our ENIG plating methods include:

  • Rack plating: We recommend this method for plating components that must meet stringent requirements for testing, deposit distribution and part tolerance. At SPC, we can accommodate orders for prototypes and small volumes as well as larger volumes.
  • Barrel plating: Barrel plating is used to efficiently coat high volumes at the same time. The largest barrel measures 17 cubic feet, so we can use this method for parts of various shapes and sizes.
  • Vibratory plating: This method provides the ideal ENIG solution for parts that are too delicate to subject to the tumbling action essential to the barrel plating process.

Plating Specifications

Depending on the application, electroless nickel immersion gold plating may need to adhere to industry-specific standards. For example, when used for printed circuit boards, you will want to consider IPC-4552. This standard outlines ENIG quality requirements for the electronics industry.

At SPC, we can provide plating services to meet many industry specifications. We serve customers in electronics, aerospace, automotive, defense and more.

Electroless Nickel Immersion Gold Plating Considerations

ENIG plating can protect against oxidation and corrosion while allowing for reliable soldering and bonding, which makes the coating popular in electronics. However, there are several factors that can limit ENIG's effectiveness.

During the electroless nickel plating process, nickel phosphorous can sometimes form. This reduces the reliability of solder joints, potentially affecting performance. When nickel phosphorous presents a concern, some companies choose electroless nickel electroless palladium immersion gold (ENEPIG). While more complicated, ENEPIG coating may be preferable for some applications.

It's important to consider the gold layer's thickness. Gold can begin to corrode the nickel layer if left in the bath too long, limiting the potential gold thickness to around 5 µin or less.

Electroless Nickel Immersion Gold Plating FAQs

What Is ENIG?

ENIG is a type of metallic coating applied to parts by submerging them in a special solution, triggering a chemical reaction and causing the metal ions to be deposited on the base material's surface. ENIG combines traditional electroless nickel with a layer of gold for enhanced performance.

What Are the Advantages of ENIG?

The two main advantages of ENIG are excellent joint solderability and corrosion resistance. In addition, protection from oxidation is a significant advantage for printed circuit boards.

What Applications Use Electroless Nickel Immersion Gold Plating?

ENIG plating serves primarily as a finish for printed circuit boards. Electroless nickel immersion gold can also find use across industries in applications that require corrosion resistance and reliability.

What Metals Can Be Plated With Electroless Nickel Immersion Gold?

Metal base materials that ENIG can adhere to include:

  • Copper
  • Aluminum
  • Steel
  • Stainless steel

Why Choose Sharretts Plating Company?

At SPC, we have decades of experience providing full-service finishing solutions for companies in a range of demanding industries. We take the time to understand your company's unique requirements and tailor our coating or finishing process to your needs. To learn more about the advantages of ENIG plating or to request a quote, fill out our contact form today.

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"I would like to thank you for the help you have provided us in developing an electroless nickel plating technique on an unusual substrate. The sample platings you provided show that we should be able to reach our goals. I especially appreciate your willingness to take on an unusual job, with the uncertainties that that entails...We are looking forward to working with you in the future on our plating needs."

– Robert K.