Protection of NdFeB magnets by ultra-thin sol-gel derived films

The exploitation of NdFeB magnets has been limited by problems of corrosion . The paper describes a novel process, to impart corrosion protection to Nd FeB powders, based upon the deposition of a stable and tenacious protective film of submicron thickness via a sol-gel route. The effect of the deposit ion conditions and coating composition, together with the effect of reactio n modifying additives are discussed, and related to the relative performanc e of the coating in imparting corrosion protection. The process could be ex ploited to extend the durability of and range of applications for these mat erials. (C) 1999 Elsevier Science S.A. All rights reserved.