About NdFeB magnet: Neodymium iron boron ( NdFeB) is a type of rare earth magnetic material. NdFeB is the most advanced commercialized permanent magnet material available today. This material has similar properties as the samarium cobalt except that it is more easily oxidized and generally doesn't have the same temperature resistance. However, NdFeB magnets have the highest energy products approaching 52MGOe and are mechanically stronger than samarium cobalt magents. NdFeB material is more costly by weight than ceramic or alnico but produces the highest amount of flux per unit of volume or mass amking it very economical for many applicantions. Their high energy products lend themselves to comnpact designs that result in innovative applications and lower manufacturing costs. Unprotected NdFeB magnets are subject to corronsion. Surface treatments has ben developed that allow them to be used in most applications. These treatments include copper, silver,, gold, nickel, zinc and tin plating and epoxy resin coating. Beneficial characteristics of NdFeB magnets include their very high energy product, very high coercive force, and moderate temperature stability. Drawbacks include lower mechanical strength, and low corrosion resistance when not properly coated or plated. Magnetic Grades and Temperature: The Grade of a magent directly refers to the Maximum Energy Product of the material that composes the magnet. It in no way refers to the physical properties of the magnet. Grade is generally used to describe how "strong" a permanent magnet material is. The energy products is specified in the unites Gauss Oersted. One MGOe is 1,000,000 Gauss Obersted. A grade forty (N40) would have a Maximum Energy Product of 40 MGOe.The higher the grade the "stronger" the magnet. Magnetic materials have a wide range of working temperatures. The following chart the various materials and their maximum working temperature. NdFeB material