Graphene coating obtained in a cold-wall CVD process on the Co-Cr Alloy (L-605) for medical applications

Graphene coating on the cobalt-chromium alloy was optimized and successfully carried out by a cold-wall chemical vapor deposition (CW-CVD) method. A uniform layer of graphene for a large area of the Co-Cr alloy (discs of 10 mm diameter) was confirmed by Raman mapping coated area and analyzing specific G and 2D bands; in particular, the intensity ratio and the number of layers were calculated. The effect of the CW-CVD process on the microstructure and the mor-phology of the Co-Cr surface was investigated by scanning X-ray photoelectron microscope (SPEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Nanoindentation and scratch tests were performed to determine mechanical properties of Co-Cr disks. The results of microbiological tests indicate that the studied Co-Cr alloys covered with a graphene layer did not show a pro-coagulant effect. The obtained results confirm the possibility of using the developed coating method in medical applications, in particular in the field of cardiovascular diseases

Graphene Coating Obtained in a Cold Wall CVD Process on the Co Cr Alloy L 605 for Medical Applications

Graphene coating on the cobalt chromium alloy was optimized and successfully carried out by a cold wall chemical vapor deposition CW CVD method. A uniform layer of graphene for a large area of the Co Cr alloy discs of 10 mm diameter was confirmed by Raman mapping coated area and analyzing specific G and 2D bands; in particular, the intensity ratio and the number of layers were calculated. The effect of the CW CVD process on the microstructure and the morphology of the Co Cr surface was investigated by scanning X ray photoelectron microscope SPEM , atomic force microscopy AFM , scanning electron microscopy SEM , and energy dispersive X ray spectroscopy EDS . Nanoindentation and scratch tests were performed to determine mechanical properties of Co Cr disks. The results of microbiological tests indicate that the studied Co Cr alloys covered with a graphene layer did not show a pro coagulant effect. The obtained results confirm the possibility of using the developed coating method in medical applications, in particular in the field of cardiovascular disease

Microstructure and Thermomagnetic Properties of As-Quenched Gd₇₅Ge₁₅Si₅Pr₅ Alloy

Microstructure and thermomagnetic properties of the as-quenched Gd₇₅Ge₁₅Si₅Pr₅ (wt.%) alloy are studied. Multiphase composition of the investigated sample was confirmed by microstructural as well as magnetic investigations. The presence of the Gd₆₈Ge₁₈Si₇Pr₇ and Gd₇₆Ge₁₄Si₅Pr₅ regions with different atom concentration was confirmed by SEM/EDS analysis and temperature dependence of magnetic mass susceptibility. From DC magnetic measurements of magnetization versus temperature performed in zero-field/field cooled modes, and magnetic mass susceptibility investigations the Curie temperature (283 K and 278 K, respectively) and magnetic behavior were studied. Moreover, the structural investigations were performed as temperature dependence of specific heat capacity

Magnetic Properties of Ion Irradiated Fe₇₅Mo₈Cu₁B₁₆ Metallic Glass

Microstructure and thermomagnetic properties of ion-bombarded amorphous Fe₇₅Mo₈Cu₁B₁₆ alloy are investigated. The Mössbauer spectroscopy shows that surface regions at the air side of the ribbons irradiated with 2×10¹⁶ ions/cm² were significantly affected by 130 keV N⁺ ions. On the other hand, the opposite (wheel) side that was not exposed to ion irradiation is practically intact. The analysis of temperature dependences of magnetization shows the Curie points of 313 K and 316 K for as-quenched and irradiated samples, respectively. The maximum of magnetic entropy change calculated for the irradiated alloy in a magnetic field of 1.0 T occurs at 312.5 K and equals to 0.77 J kg¯¹ K¯¹ while that of the as-quenched sample is 0.74 J kg¯¹ K¯¹

Thermomagnetic Properties and First-Order Reversal Curve Analysis of Annealed Fe-Co-Si-B-Mo-P Alloy

The paper presents thermomagnetic features and characterization of magnetic interactions in the Fe₅₁Co₁₂Si₁₆B₈Mo₅P₈ metallic glass after annealing at 798 K for 1 h. The first-order reversal curve analysis was used to investigate hysteresis curves which provide a more precise estimation of the strength of interactions. The presence of magnetically distinct regions was revealed

Impact of Ion-Irradiation upon Microstructure and Magnetic Properties of NANOPERM-Type Fe₈₁Mo₈Cu₁B₁₀ Metallic Glass

Microstructure and soft magnetic properties of the Fe₈₁Mo₈Cu₁B₁₀ amorphous alloy in the as-quenched state and after irradiation with N⁺ ions are investigated. CEMS spectra show that the irradiated surface at the air side of the ribbons was significantly affected. On the other hand, no noticeable changes were observed at the opposite wheel side. More deep subsurface regions are also not altered as evidenced by CXMS spectra. Thermomagnetic measurements have shown presence of two magnetically different phases with well distinguished Curie points. They can be ascribed to the amorphous matrix and crystalline phases. The latter were quenched-in during the production process and/or induced by ion bombardment. Curie temperatures of the amorphous matrixes were calculated using the Heisenberg model. For the as-quenched and irradiated ribbons they are of 223 K and 228 K, respectively. The behaviour of coercivity versus temperature was also analysed

Investigation of Critical Behavior in Gd₇₅Ge₁₅Si₅Ce₅ Alloy

The main goal of the present work was to study the critical behavior in the as-quenched Gd₇₅Ge₁₅Si₅Ce₅ (wt%) in the vicinity of the critical temperature T_{C}. The second order phase transition from a ferro- to a paramagnetic state was confirmed by the positive slope of the Arrott plots and analysis of temperature evolution of the Landau coefficients. The critical exponents have been revealed using the Kouvel-Fisher method and yield β=0.376±0.006, γ=1.032±0.006 and δ=3.835±0.008. The Curie temperature for the as-quenched Gd₇₅Ge₁₅Si₅Ce₅ equals 275.7±0.1 K

Investigations and Applications of Nanoperm-Type Soft Magnetic Materials

The microstructure and magnetic properties of $Fe_{82}Zr_4Nb_3B_{10}Cu_1,$ $Fe_{80}Zr_4Mn_3B_{12}Cu_1$ and $Fe_{80}Zr_4Ti_3Cu_1B_{12}$ alloys were investigated. Using RALE software the basic parameters of transformers made from nanocrystalline alloys with about 25% and 50% of crystalline phase were calculated. The transformer made from $Fe_{80}Zr_4Ti_3Cu_1B_{12}$ alloys after annealing at 773 K for 1-shows the lowest core losses and highest efficiency

Magnetocaloric Properties of Fe₇₅Mo₈Cu₁B₁₆ and Fe₈₁Mo₈Cu₁B₁₀ Metallic Glasses

Microstructure and thermomagnetic properties for the Fe₇₅Mo₈Cu₁B₁₆ and Fe₈₁Mo₈Cu₁B₁₀ metallic glasses in the as-quenched state and after heat treatment at 643 K and 723 K are studied. The inverse change of the Curie point was observed for Fe₇₅Mo₈Cu₁B₁₆ metallic glass after annealing below the onset of crystallization. It is attributed to structural relaxation of the amorphous phase. The maximum of magnetic entropy change calculated for magnetic field of 1.0 T occurs for the Fe₇₅Mo₈Cu₁B₁₆ alloy annealed at 643 K at temperature close to the Curie point and equals 0.74 J kg¯¹ K¯¹