In this paper, titanium and chromium nitride coatings on pure polycrystalline nickel wee obtained by dynamic ion beam mixing. Chemical composition and microstructure of the surface layers were examined by AES, XRD, TEM, and their effects on corrosive properties as well Ti-DIBM specimen fatigue behaviour were studied. Composition analyses by AES show that only the part of condensing layers is mixed with the substrates. Because nickel exhibits ultra-fast solut diffusion in α-Ti, the mixed profile extends to surface. TEM analyses show that the Ti-DIBM specimen surface region consists of titanium oxide, collum grown α-Ti, TiC, Ti_2NiHo.5 phases and the cell structure of dislocations; The CrN-DIBM specimen surface region consists of Cr-N-C amorphous, Cr_2(CN), Cr(b.c.c), Cr(cubic), Ni-Cr amorphous phases and the cell structure of dislocations. The three-sweep potentiokinetic measureent of the specimens in deaerated 1M NaAc/HAC (PH6.7, 25 ℃) shows that corrosion resistance is improved significantly. The critical current density and the minimum anodic passivating current density are lowered by about one or two orders of magnitude, respectively, and the latter is better than the former. Ti-DIBM specimen corrosion resistance improvement is attributed to the oxide surface layer. Ti-DIBM specimen corrosion resistance improvement is attriuted to the oxide surface layer. CrN-DIBM specimen corrosion resistance imporovment is attributed to the amorphous surface layer. The microhardness of pure polycrystalline nickel with Ti-DIBM and CrN-DIBM is improved. It was found that the fatigue life of all Ti-DIBM specimens are lower than that of untreated ones in load unload tensile fatigue under stress-controlled condition. That is attributed to it that fatigue cycle stress leads the surface layers to crack and fatigue cracks are accelerated to initiate in many places.
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