Thin coatings can provide significant shielding against low frequency EMF/magnetic fields

Both military and commercial organizations have concerns about obtaining electromagnetic shielding performance using materials that maintain long term performance in today´s increasingly hostile shipboard and commercial environments. This paper describes the development and testing of several unique coatings consisting of mixtures of semiconductive and conductive nano-particles of both magnetic and nonmagnetic materials. These materials exhibit low frequency shielding characteristics and have demonstrated significant EMI shielding performance against low frequency, near field magnetic sources previously unobtainable using traditional coatings. Shielding performance of over 20 dB for a 100 micron thickness at the 60 Hz powerline frequency has been measured against a solenoidal EMI source. Although performance at the powerline frequencies was the original goal, the validation of performance over a wider frequency band was documented