Calcium metal electrode, deposition

This reference electrode system is suitable for use between 700 and 950 °C, below which the reference system has too high impedance (typically above 10 2) and above which the silver melts T = 962 °C). Internal standards are used to measure the stability of the electrode. Here, reduction of silicon dioxide and calcium metal deposition (from Ca " ) can be used as indicator potentials and show that the electrode can give stable potentials for times between hours and days. In practice, while carrying out long electrolysis reactions in chloride melts, the group at CSIRO (Australia) have found that the electrodes typically last about 8 h. This is, however, sufficient to carry out many types of experiments. 

Nanoscale components can be coated on the material surtaces via electrodeposition. He et al. (2010) demonstrated the use of this technique by mineralizing calcium phosphate on PLA nanofibers. The PLA nanofibers were collected on metal electrodes used for the fabrication process of electrodeposition. The calcium phosphate coating was deposited on the electrodes containing the PLA nanofibers. The authors have also varied the topography of the surface by changing the electrodeposition process parameters. 

In the many reports on photoelectron spectroscopy, studies on the interface formation between PPVs and metals, focus mainly on the two most commonly used top electrode metals in polymer light emitting device structures, namely aluminum [55-62] and calcium [62-67]. Other metals studied include chromium [55, 68], gold [69], nickel [69], sodium [70, 71], and rubidium [72], For the cases of nickel, gold, and chromium deposited on top of the polymer surfaces, interactions with the polymers are reported [55, 68]. In the case of the interface between PPV on top of metallic chromium, however, no interaction with the polymer was detected [55]. The results concerning the interaction between chromium and PPV indicates two different effects, namely the polymer-on-metal versus the metal-on-polymer interface formation. Next, the PPV interface formation with aluminum and calcium will be discussed in more detail. 

The electrolysis Of fused alkali salts.—Many attempts have been made to prepare sodium directly by the electrolysis of the fused chloride, since that salt is by far the most abundant and the cheapest source of the metal. The high fusion temp. the strongly corrosive action of the molten chloride and the difficulty of separating the anodic and cathodic products, are the main difficulties which have been encountered in the production of sodium by the electrolysis of fused sodium chloride. Attention has been previously directed to C. E. Acker s process for the preparation of sodium, or rather a sodium-lead alloy, by the electrolysis of fused sodium chloride whereby sodium is produced at one electrode, and chlorine at the other but the process does not appear to have been commercially successful. In E. A. Ashcroft s abandoned process the fused chloride is electrolyzed in a double cell with a carbon anode, and a molten lead cathode. The molten lead-sodium alloy was transported to a second chamber, where it was made the anode in a bath of molten sodium hydroxide whereby sodium was deposited at the cathode. A. Matthiessen 12 electrolyzed a mixture of sodium chloride with half its weight of calcium chloride the addition of the chloride of the alkaline earth, said L. Grabau, hinders the formation of a subchloride. J. Stoerck recommended the addition of... 

This is the case for magnesium and calcium electrodes whose cations are bivalent. The surface films formed on such metals in a wide variety of polar aprotic systems cannot transport the bivalent cations. Such electrodes are blocked for the metal deposition [28-30], However, anodic processes may occur via the breakdown and repair mechanism. Due to the positive electric field, which is the driving force for the anodic processes, the film may be broken and cracked, allowing metal dissolution. Continuous metal dissolution creates an unstable situation in the metal-film and metal-solution interfaces and prevents the formation of stable passivating films. Thus, once the surface films are broken and a continuous electrical field is applied, continuous metal dissolution may take place at a relatively low overpotential (compared with the high overpotential required for the initial breakdown of the surface films). Typical examples are calcium dissolution processes in several polar aprotic systems [31]. 

Vanadium is obtained from many of the extracts, either by precipitation as ferrous vanadate or calcium vanadate or by electrolytic deposition. If ferrous sulfate is used, it must be present in considerable excess in order to prevent loss of vanadium. The electrolytic deposition has some advantages over the precipitation methods, but it does not produce a pure product. If ferrous vanadate is desired, a nearly neutral solution is used, the anode is iron and the cathode almost any metal. A potential difference between the electrodes of four volts is suffi-... 

The various tunable properties of zeolites have inspired a great variety of concepts in electrochemistry with zeolite-modified electrodes. For example, silver ions inside the zeolite pore system arc not electrochemically active in amperometric detection. Flowever, indirect analyte detection can occur when the analyte causes the removal of silver ions into the solution where they are electrochemically detected.[94] This indirect approach was extended to different copper-exchanged zeolites and demonstrated for the detection of several non-elcctroactive ions including alkali metal, ammonium and calcium.[95] A zeolite-modified electrode (ZME) with high selectivity towards Pb over Cd in cyclic voltammetry was prepared via electrophoretic deposition of zeolite Y, coated with Nafion.[96]... 

---