Ordinary Plating and Coatings on Our Neodymium Magnets

Why do Rare Earth Neodymium magnets need to be plated? Magnets can only be electro-plated before magnetization. if the plating is compromised after magnetization via abrasion or deliberate machining they cannot be re-plated. Some coatings such as plastic may be done after magnetization, If the process does not exceed the magnets maximum operating temperature. Oxidization (rust):NdFeB magnets will oxidize(rust) if left exposed. When a plating wears down or cracks, the exposed area will oxidize. An oxidized area will not result in complete degradation of the magnet, only the oxidized area will lose its strength. However the magnet will lose some structural integrity and become more susceptible to breakage. Durability:Depending on shape, permanent magnet substrate is brittle. A multilayered metal plating like nickel or zinc improves the magnets resistance to chipping and wear, particularly around corners. Harsh Environments: Plating vary in their tolerance of different harsh chemicals and abrasion. Salt and humidity in regions near the ocean are commonly overlooked when selecting a plating. Be sure to consider the magnets environment when selecting a plating. The most common type of plating for neodymium magnets Nickel (Ni-Cu-Ni) Intended for indoor use. It has proven to be very resilient when subjected to normal wear and tear. However it will corrode outdoors in prolonged exposure to salt water, salty air, or harsh chemicals. Nickel (Ni-Cu-Ni):The coating thickness will be around 10-20 Microns. A very durable multi-layers combination of nickel, copper, nickel. The most common plating. Nickle plating is with good resistance to Abrasion&wear, Humidity, while Bad to Salty air , water & salty Water. Zinc Plating (Zn):The coating thickness will be around 8-10 Microns.2nd most common plating, Zinc is a standalone plating with only one layer. It is a self- sacrificing coating, meaning when the material corrodes the outside turns white creating a durable layer of protection. Zinc plating is with good resistance to water, salty air ( Near Ocean), while bad to salty water. Epoxy (Ni-Cu-Be):The coating thickness will be around 15-25 Microns.Epoxy plating is multilayered in Nickel, Copper, Epoxy. Great for outdoor applications. However it is not very abrasion resistant and prone to scratching. Gold (Ni-Cu-Au):The coating thickness will be 10-20 Microns. Well known for its corrosion resistance. Layered in Nickel, Copper & Gold on top. Works very well in water applications.The gold layer is very thin and adds only a few cents per magnet. Plastic:The coating thickness will be 250-500 Microns. Plastic is the most corrosion resistant. However its is thicker than other plating. A mold is required to create the plastic shell. Phosphate:Phosphate is a temporary coating that will last only a few months. It is normally used when the magnet is going to be over-molded or encased in a plastic part that will act as the final protective layer.