Nd-Fe-B permanent magnet material of an extremely high content of Nd is liable to severe corrosion,due to the oxidizing of
Nd.Fortunately,it could be feasible to significantly increase the corrosion resistance of the
Nd-Fe-B permanent magnet material making use of electroless plating of various metal and/or alloy systems.Thus the corrosion behavior of the Nd-Fe-B permanent magnet material in electroless copper plating bath,acidic electroless Ni-P plating bath,neutral electroless Ni-P plating bath,alkaline eletroless Ni-P plating bath,and alkaline
degreasing solution was investigated.Moreover,its corrosion behavior in nitric acid solutions of pH values 1,3,and 5,respectively,and sodium hydroxide solutions of pH values 8,10,and 12,respectively,was also examined at various temperatures.The E-t curves for the Nd-Fe-B in different mediums were measured.It was found that the corrosion rate of the Nd-Fe-B material decreased with increasing pH value of the mediums.Almost no weight loss attributed to corrosion was observed as the pH value of the mediums was above 10.Moreover,the static state experimental results were validated by the corresponding E-t curves.In general,it was suggested to clean the Nd-Fe-B substrate using alkaline degreasing solution and to introduce a bottom deposit using alkaline electroless copper plating prior to the final electroless plating,so as to minimize the possible corrosion of the Nd-Fe-B substrate in different bath systems.