Guzman, D., Garcia, C., Soliz, A., Sepulveda, R., Aguilar, C., Rojas, P., et al. (2018). Synthesis and Electrochemical Properties of Ti-Si Alloys Prepared by Mechanical Alloying and Heat Treatment. Metals, 8(6), 417.
Abstract: The aim of this work was to study the synthesis and electrochemical properties of Ti 2 wt %-Si alloys prepared by mechanical alloying (MA) and heat treatment. The MA process was performed under Ar atmosphere. The structural, morphological, and compositional evolutions during the milling and subsequent heat treatment were investigated by X-ray diffraction, energy-dispersive spectroscopy, and scanning electron microscopy. The electrochemical behavior was evaluated by open circuit potential and linear sweep voltammetry measurements. The results showed that the MA process promotes the formation of a supersaturated alpha-Ti-Si solid solution. During heat treatment, the Si remaining in the mechanically alloyed powders and the Si from the alpha-Ti-Si supersaturated solid solution reacted with Ti to form Ti-Si intermetallic compounds. These compounds have a fine and homogeneous distribution in the alpha-Ti matrix, which cannot be achieved by conventional casting methods. Additionally, the electrochemical evaluations revealed that the mechanically alloyed and heat-treated Ti 2 wt %-Si powders have better corrosion resistance in 1.63 M H2SO4 than the pure Ti and MA Ti-Si samples. This is likely due to the particular microstructure produced during the milling and subsequent heat treatment.
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Sanhueza, L., Garrido, K., Celis, F., Garcia, M., Caceres, C., Moczko, E., et al. (2023). Tailoring the electroactive area of carbon screen-printed electrodes by simple activation steps towards rutin determination. J. Solid State Electrochem., 27, 1511–1521.
Abstract: Screen-printed electrodes (SPEs) have the advantage of being considered electrochemical cells that can be implemented in portable sensor applications. With the aim to improve the SPE performance, herein, we present different electrochemical surface modifications of carbon-based SPEs by cyclic voltammetry in hydrogen peroxide or sodium peroxide solution. SPEs were characterized using contact angle, Raman spectroscopy, laser-induced breakdown spectroscopy (LIBS), and electrochemical methods, including cyclic voltammetry (CV), electrochemical impedance spectroscopy, and square wave voltammetry (SVW). Main results agree with the observed changes by Raman spectroscopy and the sp(2)/sp(3) ratio (I-D/I-G) of carbon vibrational bands. The diminishing of C-2 Swan signal determined by LIBS suggests that the activation steps produced defects onto the working electrode in the SPE. Considering that the different intermolecular forces of the redox couples are useful to indirectly evaluate the different functional groups, the activated SPEs were studied in the presence of rutin and [Fe(CN)(6)](3-)/[Fe(CN)(6)](4-) redox couples. Main results show that the electrochemical response of the activated electrode surfaces can be properly used to improve the rutin electrochemical determination.
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