The Measurement of Mixed Potentials Using Platinum Decorated Nanoporous Gold Electrodes

Potentiometric redox sensing in solutions containing multiple redox molecules was evaluated using in-house constructed nanoporous gold (NPG)-platinum (Pt) and unmodified NPG electrodes. The NPG-Pt electrode was fabricated by electrodepositing Pt into the nanoporous framework of a chemically dealloyed NPG electrode. By varying the concentration of the Pt salt and the electrodeposition time, different amounts of Pt were introduced. Characterization by SEM shows the pore morphology doesn’t change with the addition of Pt and XPS indicates the electrodes contain ∼2.5–24 wt% Pt. Open-circuit potential (OCP) measurements in buffer and solutions containing ascorbic acid, cysteine, and/or uric acid show that the OCP shifts positive with the addition of Pt. These results are explained by an increase in the rate of the oxygen reduction reaction with the addition of Pt. The overall shape of the potentiometric titration curves generated from solutions containing one or more bioreagents is also highly dependent on the amount of Pt in the nanoporous electrode. Furthermore, the generation of OCP vs Log [bioreagent] from the results of the potentiometric experiments shows an ∼2-fold increase in sensitivity can result with the addition of Pt. These results indicate the promise that these electrodes have in potentiometric redox sensing.

Effect of ZrB2 Functionalized Nanoparticles Growth on Microstructural and Corrosion Resistance on Mild Steel through Electrodeposition Route

In other to have a better performance of Ni-P-Zn multifunctional applications, crystallite-like Ni-P-Zn-ZrB2 composite was actively fabricated by electrodeposition principle. The corrosion, structural evolution and surface active phenomena were investigated by various techniques. The influence of ZrB2 particulate on the morphology and corrosion properties was examined. The outcomes show an inclusive flower-like doped ZrB2 phase constituent and is uniformly distributed Ni-P-Zn-ZrB2 improved strengthening effect. The corrosion progression of the developed metal alloy was compared with other coating matrix from 10-25 minutes interval. The integration of ZrB2 on Ni-P-Zn phase especially for 25 min deposits significantly enhances corrosion resistance due to good grain refinement. Keywords: Ni-based composite, electrodeposition, time difference, coating, corrosion

Effect of the variation of the electrodeposition time of hydroxyapatite/chitosan coatings on AISI 316L SS

Type AISI 316 L Stainless Steel (316 L SS) plays a crucial role in bone replacement surgery due to its excellent mechanical features, availability at low cost, and ease of fabrication, but its performance is low when in contact with the aggressive conditions of the human body fluids. Chitosan (CTS) is a biopolymer that blended with hydroxyapatite (HAp) could form coatings to improve surface properties of a metallic orthopedic prosthesis, i.e., corrosion-resistance to the base metal and biocompatibility of the ceramic on the metal surface. This work aims to obtain and evaluate HAp/CTS composite coatings deposited on the surface of AISI 316 L SS substrate by electrophoretic deposition (EDP) technique. The influence of the time of deposition on the coating’s characteristics and properties was characterized and discussed. The coatings were structural, elemental, and chemically characterized using X-Ray diffraction and Raman spectroscopy. HV values in a range of 64.7 to 111.5 were observed, showing the lowest HAp/CTS-30.0 coating values for all the loads applied. The lowest HV value was nearby to the reported value for human bone’s hardness, around 47HV; considering that the coating will be in constant contact motion with the bone surface, the contact with a softer surface could decrease the wear on the human bone. The hardness decreases with the coating thickness’s increment because the coating presented a higher plastic deformation than the 316 L SS surfaces. A decrease in the roughness average (Ra) was well noticed as the deposition time increased; meanwhile, the thickness increased as the deposition time increased.

Cerium Stearate Electrodeposited Superhydrophobic Coatings for Active Corrosion Protection of Anodized AA 2024-T3

The present study investigated the active corrosion protection provided by superhydrophobic cerium stearate coatings. Superhydrophobic cerium stearate was deposited on anodized AA 2024-T3 at 40 V with different electrodeposition times using a simple DC electrodeposition technique to know the role of electrodeposition time on surface morphology, hydrophobicity, and corrosion resistance. We characterized the structure and morphology of cerium stearate to understand its formation mechanism. Electrodeposition process at 40 V for 120 min resulted in the formation of dual scale Allium giganteum like micro/nano hierarchical texture of cerium stearate with a water contact angle (WCA) of 165 ± 1.6°. The cerium stearate coating obtained for 120 min process time had excellent self-cleaning property and good chemical stability, environmental stability, and mechanical durability acceptable for industrial applications. Electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET) were used to investigate the active corrosion protection of cerium stearate coating. The electrodeposited cerium stearate coating showed active corrosion protection based on self-healing ability by releasing cerium (Ce3+) ions.

Effect of Polypyrrole-Fe3O4 Composite Modified Anode and Its Electrodeposition Time on the Performance of Microbial Fuel Cells

Anode modification is a useful method to increase the performance of microbial fuel cells (MFCs). By using the electrochemical deposition method, Fe3O4 and polypyrrole (PPy) were polymerized on a carbon felt anode to prepare Fe3O4-PPy composite modified anodes. In order to ascertain the effect of electrodeposition time on characteristics of the modified electrode, the preparation time of the modified electrode was adjusted. The modified anodes were used in MFCs, and their performances were evaluated by analyzing the electricity generation performance and sewage treatment capacity of MFCs. Experimental results indicated that the Fe3O4-PPy composite modified anodes could enhance the power production capacity and sewage treatment efficiency of MFC effectively. In particular, when the deposition time was 50 min, the modified anode could significantly improve the MFC performance. In this case, the steady-state current density of MFC increased by 59.5% in comparison with that of the MFC with an unmodified carbon felt anode, and the chemical oxygen demand (COD) removal rate was 95.3% higher than that of the unmodified anode. Therefore, the Fe3O4-PPy composite is an effective material for electrode modification, and a good anode modification effect can be obtained by selecting the appropriate electrodeposition time.

Preparation and Mechanical Properties of Layered Cu/Gr Composite Film

Graphene (Gr) has proved its significant role as a reinforcement material in improving the strength of metal matrix composites due to its excellent mechanical properties. In this paper, Gr/Cu composite film with a layered structure was prepared by layering electrodeposition. The directional distribution of Gr in the Cu film was insured by this method, which gives play to its ultra-high-strength in a two-dimensional plane. In the meantime, the effect of electrodeposition time on the distribution structure of the Gr layer was studied. The structure analysis and mechanical properties test show that the strength of the layered Gr/Cu composite film is greatly improved compared to the pure Cu film. Furthermore, the strength of the composite film increases at the beginning and then decreases with the electrodeposition time of the Gr layer increasing, while the coverage and the degree for the layer stacking of Gr gradually increase in this process. In conclusion, the influence of different Gr distributions on the mechanical properties of the composite film has been studied by combining the experimental results with molecular dynamics simulation, which lays an effective foundation for further optimizing the structure of Gr in the layered composite film and improving the mechanical properties.