Plating & Coating

Corona discharge is a process in which electric current flows from a charged object (electrode) to an uncharged fluid, thereby causing the generation of ionic molecules near the electrode. The tip discharge refers specifically to the corona discharge phenomenon caused by sharp objects in corona discharge. In coating industry, we also call it tip effect or bone effect. How does the tip effect affect electroplating?Answer: When the process does not conform to the standard.The tip effect tends to cause thickening, burrs, or scorching of the coating on the tip or edge of the product. Therefore, we should try to eliminate or control the impact of tip effect to ensure product quality.  How to reduce or eliminate the tip effect, in actual operation, different measures should be taken according to different situations: control the current density; adjust the composition of the plating solution; add appropriate additives;change the pH value of the plating solution; add auxiliary poles to the workpiece; adjust the distance between cathode and anode; change the geometry of the anode and the electroplating bath; change the suspension mode and position of the workpiece, etc.

  All you need to know about Teflon Plating \ Coating Descr. Indoor Use Abrasion Humidity Water Salty Air / Near Ocean Salt Water Glue Thickness Price Nickel (Ni-Cu-Ni) A very durable multilayer combination of nickel, copper, nickel. Excellent Good Good Bad Bad Bad Bad 10-20 Microns Low Zinc Plating (Zn) 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. Excellent Excellent Excellent Good Good Bad Good 8-10 Microns Low Gold (Ni-Cu-Au) 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. Superior Good Superior Superior Superior Superior Bad 10-20 Microns High Black Epoxy (Ni-Cu-Be) Epoxy plating is multilayered in Nickel, Copper, Epoxy. Great for outdoor applications. However, it is not very abrasion resistant and prone to scratching. Superior Bad Superior Superior Excellent Excellent Good 15-25 Microns Medium Raw Epoxy (BE) This coating does not have underlying coats of Nickel or Copper Superior Good Superior Superior Excellent Excellent Superior 10 - 20 Microns 　 Plastic Plastic is the most corrosion resistant. However its is thicker than other platings. A mold is required to create the plastic shell. Superior Superior Superior Superior Superior Superior Excellent 250-500 Microns Medium Teflon Very efficient coating widely used in various industries. Waterproof seal to protect the magnet inside. Superior Superior Superior Superior Superior Superior Bad 250 - 500 Microns High 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.  Good Bad Bad Bad Bad Bad Bad 1-2 Microns Low

Moisture in the atmosphere is potentially enough to cause an uncoated NdFeB magnet to show signs of corrosion. Marine environments are particularly effective at makingNdFeB magnets corrode. The process of corrosion is similar to rusting – the structure of the Neodymium Iron Boron magnets changes permanently resulting ina progressive loss in magnetic performance (the magnet will weaken; the magnet also breaks down into a powder during the corrosion process). Total magnetic failure is possible due to corrosion. To prevent this, the magnet is given a coating / surface finish. The standard coating is a triple layer plating of Nickel-Copper-Nickel (Ni-Cu-Ni). Unless requested otherwise, this Ni-Cu-Ni coating is always applied to the magnets. It should be noted that the level of protection given by any coating depends on the environment the magnet will be subjected to and how the coating is looked after. If the coating is scratched or broken, it will not offer protection fromvmoisture.

Choosing different coatings does not affectthe magnetic strength or performance of the magnet, except for our Plastic and Rubber Coated Magnets.  The preferred coating is dictated by preference or intended application.  More detailed specifications can be found onour Specs page.Nickel is the most common choice for plating neodymium magnets.  It is actually a triple plating of nickel-copper-nickel. It has a shiny silver finish and has good resistance to corrosion in many applications.  It is not waterproof.Black nickel has a shiny appearance in achar coal or gunmetal color.  A black dyeis added to the final nickel plating process of the triple plating ofnickel-copper-black nickel.  NOTE: It does not appear completely black like epoxy coatings.  It is also still shiny, much like plain nickel plated magnets.Zinc has a dull gray/bluish finish, that is more susceptible to corrosion than nickel. Zinc can leave a black residue on hands and other items.Epoxy is basically a plastic coating that ismore corrosion resistant as long as the coating is intact.  It is easily scratched.  From our experience, it is the least durable of the available coatings.Gold plating is applied over the top of standard nickel plating.  Gold plated magnets have the same characteristics as nickel plated ones, but with a gold finish.