Cleaning ability With proper plating or coat […]
With proper plating or coating, you can create an easy-to-clean outer layer on the magnet. The existing production surface finish on many magnets is not enough to remove small particles and is easy to stain, but the surface finish of magnet plating or coating is much smoother, which can remove debris more thoroughly.
Magnets can attract rogue iron filings, or fragments containing ferrous metal materials. After the magnet is coated, these particles can be easily removed, greatly reducing the worry of surface cracking due to accumulation of foreign matter. The coating also prevents the substrate material from falling off and the particles from being released from the magnet alloy by wrapping the magnet and containing particles.
The conductivity of most magnet alloys is low to moderate compared to traditional materials used for electrical connections. Adding metal plating will affect conductivity. Certain coatings (such as gold) can increase conductivity and improve the effectiveness of magnets in certain applications.
Magnetic alloys are very brittle and easily chipped and broken due to mechanical stress and impact. The metal plating or conformal coating adds a layer of protection to the magnet. The best protection is multi-layer electrolytic plating involving nickel, because nickel has twice the tensile strength of the magnet alloy base material and reduces or eliminates mechanical penetration of the magnet. Therefore, compared with the force required to destroy an unplated samarium-cobalt magnet, a nickel-plated samarium-cobalt magnet requires a greater force to destroy it.
In certain applications, such as healthcare, low-reactivity coatings may be required to provide an inert interface between the magnet and human tissue. For example, in the case of implants, a conformal coating can produce a low-reactivity surface. A common coating option is parylene, which is used to encapsulate substrates in medical applications, where magnets need to be isolated from body fluids. Magnets used in medical equipment are usually electroplated first and then coated with parylene; this also helps the magnet to withstand autoclave sterilization, otherwise it may cause the magnet to rust.
Finally, coating and electroplating can reduce or even eliminate outgassing that may pose a hazard to precision equipment.
Many magnet alloys are not completely dense because they are made by compressing powdered metal in a process called sintering. This makes the magnet semi-porous and susceptible to moisture, chemicals and atmospheric gases. When integrated into your application, magnets may degas these materials, causing contamination or interfering with proper operation.
Sensitive equipment rarely tolerates contamination, so coatings are used to prevent outgassing. For example, magnets used for optical lasers can be plated with nickel and encapsulated in parylene to separate the magnet alloy matrix from the vacuum.