KOLCHUGINA Natalia VSB-Technical University of Ostrava

Spoluautoři LUKIN Aleksandr, BURKHANOV Gennadii, SPRYGIN Georgii, KURSA Miroslav, SKOTNICOVA Katerina,

Diamond-like coating (DLC) was deposited on grinding and polished surfaces of Nd-Fe-B sintered magnet (prepared with 4% TbH2) using reactive ion-beam synthesis directly from ion beam of a chemical complex substance (cyclohexane). The film deposited is diamond-like; the fraction of tetragonal carbon-atom bonds is 70%. The composition and thickness of the coating was analyzed by glow-discharge spectroscopy using a GDS 850A (LECO) spectrometer. The thickness of pure carbon (DLC) layer is 0.08 μm. The existence of transition layer 0.08-0.07 μm thick is due to the diffusion (to a lesser degree) and surface roughness. The effect of the coating of surface mechanical characteristics of the magnet was estimated in studying the Vickers hardness of the surface and friction coefficient and by nanoindentation and scratching tests as well. The Nd-Fe-B magnets with applied diamond-like coating demonstrate the lower tendency to mechanical cracking. The dry frictional tests showed that, after wear-in process, the DLC increases substantially the stability of frictional process and decreases the frictional coefficient in the cases of both unchanged and progressively increasing load. The decrease in the frictional coefficient allows the heating of magnets to be decreased. This study was performed in the frame of the project No. Cz.1.05/2.1.00/010040 “Regional Materials Science and Technology Center” and the Branch of Chemistry and Materials Science, RAS (Program no. 5).