| Bright Ni-Fe alloy coatings were prepared on 2024 aluminum alloy sheets from sulphate bath solution by electroplating. The phase compositions and structure of Ni-Fe alloy coatings were studied by using X-ray diffraction. The XRDω-scan technique was utilized to analyze the crystalline texture and the misorientation of Ni-Fe alloy coatings. The thickness of coating was measured by using scan electron microscope (SEM) and the qualitative and quantitative analysis of elemental compositions in coatings were performed by energy dispersive spectroscopy (EDS). The microstructures of coatings were observed by transmission electron microscope (TEM), and phase compositions were further determined by selected area electron diffraction. The magnetic properties of coatings were measured by vibration sample magnetometer (VSM).The results of EDS analysis show that when the FeSO4·6H2O content in the solution is 12g/L, Ni-15%Fe coating is obtained and the element content of Fe in the coatings increases by 10% as the FeSO4·6H2O content in the solution increases 1g/L.The investigation of structure by X-ray diffraction shows that very pure FeNi3 is obtained in the Ni-Fe alloy coatings by electroplating on 2024 aluminum alloy sheets.The results of SEM with Energy Spectrum Analysis indicate that the thickness of the coatings is equable, and the thickness of the coatings increases as the electroplating time increasesThe results of TEM indicate that the grains of obtained Ni-Fe alloy coatings are equiaxial, fine grains, with a average diameter about 10-20 nanometers. The results of selected area electron diffraction also show that the coatings consist of pure FeNi3.ω-scan XRD of the coatings indicate that as-electroplating coatings are (200)-textured. The dispersity of (200)-texture decreased with the electroplating time increases for the thickness of the coatings increases. The thicker thickness is favorable for the formation of (200)-textured microstructure in Ni-Fe alloy coatings. The annealed coatings are (200)-textured and (111)-textured. The thicker thickness is favorable for the formation of (200)-textured microstructure in Ni-Fe alloy coatings, while the thinner thickness is favorable for the formation of (111)-textured microstructure.The 2Theta scan XRD of the coatings indicated that as-electroplating coatings are in residual tension, while the annealed coatings are in residual compression.The results of VSM showed that compared with the as-electroplating samples the coercive force of annealed samples increase obviously. Multiple textures are favorable for the increase of coercive force and high residual stress was favorable for the increase of coercive force. |
