Microstructure evolution characteristics of industrial electrolytic nickel deposits

Abstract:

This paper studies the characteristics of the microstructure of industrial electrolytic nickel deposits changing with deposition time. XRD, SEM, EBSD and other analysis methods were used to study the preferred orientation, microstructure and characteristic grain boundary distribution of electrolytic nickel plate with the production time were studied. The results show that the crystals on the surface of the electrodeposited nickel plate mainly grow in the direction perpendicular to the (200) plane, the cross-section shows the (111) and (200) double preferred orientations, and the crystal growth method is lateral growth. The surface and the cross-section show different microstructure, the surface morphology changes from a pyramid shape to a cell shape,and the growth mechanism changes from spiral dislocation-driven growth to atom aggregation and accumulation,the cross-sectional morphology of the nickel plate is always a lamellar structure at each stage. The cross-section of the deposited layer is mainly high-angle grain boundaries and a large number of Σ3 twin grain boundaries. In the stable growth process, the proportion of large-angle grain boundaries gradually decreases as the deposition progresses, neverthless the relative frequency of Σ3 grain boundaries gradually increases, but they will all be affected by changes in the environment of the electrolytic cell. In the cross-section along the growth direction, the electrolytic nickel plate mainly shous the fiber texture of <001> direction, and a large number of Σ3 twin boundaries affect the orientation of the deposited layer.

Key words:industrial electrolytic nickel;EBSD; microstructure; preferred orientation; grain boundaries