Correlation of Morphology and Crystal Structure of Metal Powders Produced by Electrolysis Processes

Abstract

In this review paper, morphologies of metal powders produced by the constant (potentiostatic and galvanostatic) regimes of electrolysis from aqueous electrolytes are correlated with their crystal structure at the semiquantitative level. The main parameters affecting the shape of powder particles are the exchange current density (rate of electrochemical process) and overpotential for hydrogen evolution reaction. Depending on them, various shapes of dendrites (the needles, the two-dimensional (2D) fern-like, and the three-dimensional (3D) pine-like dendrites), and the particles formed under vigorous hydrogen evolution (cauliflower-like and spongy-like particles) are produced by these regimes of electrolysis. By decreasing the exchange current density value, the crystal structure of the powder particles is changed from the strong (111) preferred orientation obtained for the needle-like (silver) and the 2D (lead) dendrites to the randomly orientated crystallites in particles with the spherical morphology (the 3D dendrites and the cauliflower-like and the spongy-like particles). The formation of metal powders by molten salt electrolysis and by electrolysis in deep eutectic solvents (DESs) and the crystallographic aspects of dendritic growth are also mentioned in this review.

Implementation of the Chicot–Lesage Composite Hardness Model in a Determination of Absolute Hardness of Copper Coatings Obtained by the Electrodeposition Processes

“…For an estimation of the preferred orientation of Cu coatings, methodology based on the determination of the "Texture Coefficient", TC(hkl) and the "Relative Texture Coefficient", RTC(hkl) was applied. The detailed description of a procedure for the determination of these coefficients is presented in [21,25,26].…”

“…The Cu coating obtained from the basic electrolyte was fine-grained with mat appearance (Figure 1a), while the Cu coating obtained from the electrolyte with additives was very smooth without clear boundary among grains and had mirror bright appearance (Figure 1b). [21,25,26].…”

“…The precise estimation of the preferred orientation of Cu coatings was done by a calculation of the "Texture Coefficient" (TC(hkl)) and "Relative Texture Coefficient" (RTC(hkl)) [26,31,32], and the obtained values are presented in Table 2. The TC values larger than 1 indicate the existence of the preferred orientation, while those around 1 in- The precise estimation of the preferred orientation of Cu coatings was done by a calculation of the "Texture Coefficient" (TC(hkl)) and "Relative Texture Coefficient" (RTC(hkl)) [26,31,32], and the obtained values are presented in Table 2. The TC values larger than 1 indicate the existence of the preferred orientation, while those around 1 indicate random orientation [26,32].…”

“…The TC values larger than 1 indicate the existence of the preferred orientation, while those around 1 in- The precise estimation of the preferred orientation of Cu coatings was done by a calculation of the "Texture Coefficient" (TC(hkl)) and "Relative Texture Coefficient" (RTC(hkl)) [26,31,32], and the obtained values are presented in Table 2. The TC values larger than 1 indicate the existence of the preferred orientation, while those around 1 indicate random orientation [26,32]. As all four main diffraction peaks were analyzed, the values of RTC coefficients larger than 25% indicate the existence of the preferred orientation [26,32].…”

“…The TC values larger than 1 indicate the existence of the preferred orientation, while those around 1 indicate random orientation [26,32]. As all four main diffraction peaks were analyzed, the values of RTC coefficients larger than 25% indicate the existence of the preferred orientation [26,32]. The meaning of R in Table 2 is given in [21,26,31].…”