EFFECT OF PRETREATMENT ON ADHESION OF ELECTROLESS PLATED Ni-P COATINGS ON SINTERED Nd-Fe-B PERMANENT MAGNET
前处理对烧结钕铁硼化学镀镍结合力的影响

As it is well recognized that pretreatment is a key procedure for reaching a proper adhesion of an electroless Ni-P coating on a substrate of sintered Nd-Fe-B permanent magnet.In this respect,the effect of pretreatments of acidic cleaning and ultrasonic rinsing on the adhesion of electroless Ni-P coating was studied.SEM observation reveals that the surface morphology of magnet became much coarser with the increasing of nitric acid concentration in the pickles.When the pickles with 20~40 ml/L nitric acid,the...