Nickel Coating for Magnets

Nickel coating is thin layers of nickel that we apply to various substrates’ surfaces. One of the most common techniques is the electroplating technique. They provide some useful functions, including enhancing the substrate’s look, raising its corrosion resistance, and offering a tough, resilient surface for wear resistance.

In the electroplating industry, the processing volume of Nickel (Ni) coating ranks second only to electroplated zinc, thanks to the many excellent properties of electroplated nickel. And it accounts for about 10% of total nickel production.

Nickel coating come in a variety of surface finishing effects, including bright nickel, satin nickel, and matte nickel.

  • Bright Nickel coating is frequently employed as decorative accents because of their dazzling, mirror-like appearance.
  • Satin Nickel coating is frequently utilized in applications where a more understated appearance is required because they have a softer, less reflective finish.
  • Matte Nickel coating is frequently utilized in applications where a low-glare surface is sought because of their extremely dull, non-reflective finish.

Basics of Nickel coating

Nickel coating can be applied to a wide range of substrates, including metals, plastics, and ceramics. They are often used in automotive, aerospace, and industrial applications, as well as in the production of consumer goods such as appliances and electronics.

Nickel coating is known for their excellent corrosion resistance, making them suitable for use in environments where the substrate may be exposed to moisture or other corrosive substances. They are also highly durable and resistant to wear, making them ideal for use in high-stress applications. However, it can be expensive to apply and may require special handling and processing due to the potential for nickel allergies in some individuals.

Different types of Ni coating

1). Electroplated nickel

This type of nickel coating is applied using an electrolytic process, in which a current is used to deposit a layer of nickel onto the surface of a substrate. Substrates can benefit from electroplated Nickel coating thanks to better wear resistance, corrosion resistance, and aesthetics.

This is the most common technique that we use to apply Nickel coating onto neodymium magnets. Many coating technique suppliers use it for various products every day. It is fully optimized and less likely to have quality issues. Meanwhile, they can offer excellent cost-effectiveness, thanks to their wide applications.

2). Electroless nickel

This is a type of nickel coating that is applied using an autocatalytic chemical process rather than an electrolytic process. It offers an evenly distributed, robust, and corrosion-resistant coating that can be used on a range of substrate materials. This is one of the best surface treatment techniques in the world.

3). Nickel-chrome

This is a type of nickel coating that is applied over a layer of chromium. In applications where high temperatures and harsh conditions are a concern, nickel and chromium work together to provide a strong, corrosion-resistant coating.

4). Nickel-phosphorus

This is a type of nickel coating that is alloyed with phosphorus to improve its corrosion resistance and wear resistance. We usually use it in situations that need a lot of lubricities, like bearings and gears.

5). Nickel-tungsten

This is a type of nickel coating that is alloyed with tungsten to improve its hardness and wear resistance. We typically use it in applications requiring great wear resistance, including cutting tools and dies.

Features of Nickel coating

Nickel coating can offer several useful features, and these features make them attractive options for a wide range of applications. These features include:

1). Corrosion resistance

The strong corrosion resistance that Nickel coating can offer is one of the main benefits. The electroplated nickel layer is highly stable in the air. Metallic nickel has a strong passivation ability. It can quickly generate a very thin passivation film on the surface, which can resist the corrosion of the atmosphere, alkali, and certain acids. Therefore, it’s an excellent choice for protecting neodymium magnets for various applications.

2). Surface hardness

Neodymium magnets’ surface hardness can be increased by nickel plating, making them more durable. This can be especially helpful for parts like gears and bearings that experience a lot of scratches.

3). Wear resistance

Ni coating can also improve wear resistance in addition to increasing surface hardness. This can be helpful for components like valve seats and pump impellers that experience friction or frequent contact.

4). Enhancement of appearance

Electroplated nickel has extremely fine crystals and excellent polishing properties. Polished Nickel coating can offer a mirror-like glossy surface, while retaining its luster in the atmosphere for a long time. Therefore, electroplated Nickel coating is often used for decoration.

5). Versatility

Nickel coating is extremely adaptable, and they are applicable to a variety of metals and alloys. This makes them ideal choices for a variety of applications, from aircraft components to automobile parts.

Methods for verifying Ni coating’ quality

The Nickel coating is ignorable surface treatment techniques. But it doesn’t mean they don’t have any quality issues. We still need to be careful about their finished results on neodymium magnets.

There are several methods that can be used to verify the quality of Nickel coating:

  • Visual inspection: This is a simple and quick method that involves visual inspections on the surfaces of the Nickel coating on neodymium magnets to ensure that they don’t have defects. Usually, quality engineers can do it with their naked eyes.
  • Microscopic examination: This method involves using a microscope to inspect the surface of the nickel coating at a higher magnification. This can help to identify any defects or imperfections in the coating that may not be visible to the naked eye.
  • Surface roughness measurement: We measure surface roughness using a device such as a profilometer. This can help to ensure that the nickel coating has a smooth and even finish, which is important for many applications.
  • Adhesion testing: Adhesion testing involves applying a force to the nickel coating to see how well it sticks to the neodymium magnets. We use a cross-cut tester or a scratch tester to do this test.
  • Salt spray testing: This method involves exposing the nickel coating to a salt spray environment for a period of time and then examining the surface for signs of corrosion or other damage. Usually, the duration time depends on specific applications.
  • Thickness measurement: We use a thickness gauge to measure the thickness of the nickel coating. This can help to ensure that the coating is applied to the correct thickness for the specific application.
  • Hardness testing: It will need a Rockwell hardness tester to obtain the hardness of the nickel coating. This can help to ensure that the coating has the required level of hardness for the specific application.

Disadvantages of Ni coating

Although Nickel coating have multiple advantages, they still have a few potential disadvantages that you need to beware.

  • Sensitivity to heat: Nickel coating is not very durable to high temperatures and may not be suitable for use in very hot environments.
  • Corrosion resistance: Nickel coating is generally resistant to corrosion, but they may not be as corrosion-resistant as some other types of coatings, such as PTFE and Parylene.
  • Complexity of application: Applying a nickel coating can be a complex process, particularly if the coating needs to be applied to a complex shape or in a thin layer. This can make it more difficult to achieve a consistent and high-quality finish.
  • Allergies: Some people may be allergic to nickel, so it is important to consider this when choosing a coating material, especially the users may touch the neodymium magnets during their applications.
  • For neodymium magnets with complex shapes or small deep holes or blind holes, we can’t obtain better coating surface results with this technique.

Above is a brief introduction to Nickel coating for neodymium magnets. They are excellent choices and the most common technique that Osenc uses for most of our magnets. Feel free to contact us if you are looking for neodymium magnets with Ni.

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