The Diamond-like carbon (DLC) coating was applied on ground and polished surfaces of Nd-Fe-B sintered magnet (prepared with 4 % TbH2) using reactive ion-beam synthesis via the deposition directly from ion-beam of a complex chemical substance (cyclohexane).The composition and thickness of the coating was analyzed by glow discharge spectroscopy.The thickness of pure car bon (DLC) layer is 0.08 pro.The existence of tran sition layer 0.08-0.07 pm thick is due to the diffu sion (to a lesser degree) and surface roughness.The effect of the coating on surface mechanical charac teristics of the magnet was estimated in studying the Vickers hardness of the surface and friction coeffi cient and by scratch tests and nanoindentation as well.The Nd-Fe-B magnets with applied dia mond-like coating demonstrate the lower tendency to mechanical cracking.Dry frictional tests showed that, after wear-in process, the DLC increases substantially the stability of frictional process and decreases in the frictional coefficient in the cases of both unchanged and progressively increasing loads.The better adhesion of DLC on the polished surface is demonstrated.The obtained data allow us to pre dict the possibility of application of the DLC coating for the increase in wear-resistance of sintered Nd Fe-B magnets during their operation under sliding conditions and in moving abrasive liquid and gas media.
Baikov Institute of Metallurgy and Materials Science,Russian Academy of Sciences,Leninskii pr.,49,Mo JSC SPETSMAGNIT,Dmitrovskoe sh.58,Moscow,127238 Russia Vysoka Skola banska-Technical University of Ostrava,70833,Czech Republic,Ostrava-Poruba,17 Listopadu Voronezh State University,Urtiversitetskaya pl.,1,Voronezh,394006 Russia Baikov Institute of Metallurgy and Materials Science,Russian Academy of Sciences,Leninskii pr.,49,Mo