Electrodes base metal

Simple Oxides of Base Metals Electrodes of lead dioxide, Pb02, which in contrast to other base-metal oxides are stable in sulfuric acid are an example for a simple oxide system. In a number of cases, this electrode serves as the anode in the electrosynthesis of organic compounds in acid media. 

Multilayer capacitors with base metal electrodes (BME)... 

Kishi, H., Mizuno, Y., Chazono, H. Base-metal electrode-multilayer ceramic capadtors past, present and future perspectives. Jpn. J. Appl. Phys. 42, 1-15 (2003)... 

Since dramatic increase of palladium price during 1995 to 1997, the MLC manufactures had extreme pressure to reduce the electrode cost, and so accelerated the expansion of MLCs production with base metal electrode such as nickel and copper to substitute the palladium. Nickel metal is easily oxidized in air at elevated temperature. Therefore, the capacitor with nickel and copper inner electrode must be fired in a low oxygen pressure atmosphere. Conventional ceramics, however, have poor insulation resistance after heat treatment in such reducing atmosphere. 

Research on reducing the overvoltages at the electrode is directed towards producing better electrocatalysts. Cells with base metal electrodes (e.g. mild steel cathodes, nickel anodes) operate at, typically,... 

Figure 9 An electrochemical cell for determining time of wetness. (A) Material containing the embedded electrodes. (B) Noble metal electrodes (e.g., Pt or Cu). (C) Base metal electrodes (e.g., Fe or Zn). (From Ref. 2. Courtesy of John Wiley Sons.)...

When first developed, potentiometry was restricted to redox equilibria at metallic electrodes, limiting its application to a few ions. In 1906, Cremer discovered that a potential difference exists between the two sides of a thin glass membrane when opposite sides of the membrane are in contact with solutions containing different concentrations of H3O+. This discovery led to the development of the glass pH electrode in 1909. Other types of membranes also yield useful potentials. Kolthoff and Sanders, for example, showed in 1937 that pellets made from AgCl could be used to determine the concentration of Ag+. Electrodes based on membrane potentials are called ion-selective electrodes, and their continued development has extended potentiometry to a diverse array of analytes. 

In arc welding, the coalescence of metals is achieved through the intense heat of an electric arc, which is estabUshed between the base metal and an electrode. The processes Hsted in Table 1 are differentiated by various means of shielding the arc from the atmosphere (1 3). 

The system for shielded-metal arc welding, shown in Figure 2a, is the simplest system. It consists of the power source, electrode and holder, the base metal, and the electrical cables or leads. When the arc is stmck, a complete electrical circuit is provided. With d-c welding, the electrode maybe either negative (straight polarity) or positive (reverse polarity). Shielded metal arc welding is only used manually. 

One factor contributing to the inefficiency of a fuel ceU is poor performance of the positive electrode. This accounts for overpotentials of 300—400 mV in low temperature fuel ceUs. An electrocatalyst that is capable of oxygen reduction at lower overpotentials would benefit the overall efficiency of the fuel ceU. Despite extensive efforts expended on electrocatalysis studies of oxygen reduction in fuel ceU electrolytes, platinum-based metals are stiU the best electrocatalysts for low temperature fuel ceUs. 

Dissohition of metal is avoided by selecting a resistant material such as Pt, Pt coated on Ti, or Pt on Nb. Base metals are sometimes used, as are graphite electrodes. 

Laister and Benham have shown that under more arduous conditions (immersion for 6 months in sea-water) a minimum thickness of 0-025 mm of silver is required to protect steel, even when the silver is itself further protected by a thin rhodium coating. In similar circumstances brass was completely protected by 0 012 5 mm of silver. The use of an undercoating deposit of intermediate electrode potential is generally desirable when precious metal coatings are applied to more reactive base metals, e.g. steel, zinc alloys and aluminium, since otherwise corrosion at discontinuities in the coating will be accelerated by the high e.m.f. of the couple formed between the coating and the basis metal. The thickness of undercoat may have to be increased substantially above the values indicated if the basis metal is affected by special defects such as porosity. 

There have been numerous studies of the electrical and emission properties of conjugated polymer-, small molecule-, and molecularly doped polymer-based OLEDs. The current-voltage and radiance-voltage characteristics have been nica sured as a function of thickness of the organic layer, temperature, different metal electrodes, etc. in an attempt to understand the device physics. A major factor in hibiting progress is the purity of the organic impurities that are incorporated dur-... 

S.2.2 Carbon Electrodes Solid electrodes based on carbon are currently in widespread use in electroanalysis, primarily because of their broad potential window, low background current, rich surface chemistry, low cost, chemical inertness, and suitability for various sensing and detection applications. In contrast, electron-transfer rates observed at carbon surfaces are often slower than those observed at metal electrodes. The electron-transfer reactivity is strongly affected by the origin... 

A new technique based on electrocapillary phenomena at partially immersed solid metal electrodes has been developed by Jin-Hua et al. 146,147 jhe involves the detection of the rise of a solution... 

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