Bismuth film

This approach is an alternative to quantitative metallography and in the hands of a master gives even more accurate results than the rival method. A more recent development (Chen and Spaepen 1991) is the analysis of the isothermal curve when a material which may be properly amorphous or else nanocrystalline (e.g., a bismuth film vapour-deposited at low temperature) is annealed. The form of the isotherm allows one to distinguish nucleation and growth of a crystalline phase, from the growth of a preexisting nanocrystalline structure. 

Nevertheless the heat capacity of a carbon resistor was not so low as that of crystalline materials used later. More important, carbon resistors had an excess noise which limited the bolometer performance. In 1961, Low [61] proposed a bolometer which used a heavily doped Ge thermometer with much improved characteristics. This type of bolometer was rapidly applied to infrared astronomy as well also to laboratory spectroscopy. A further step in the development of bolometers came with improvements in the absorber. In the early superconducting bolometer built by Andrews et al. (1942) [62], the absorber was a blackened metal foil glued to the 7A thermometer. Low s original bolometer [61] was coated with black paint and Coron et al. [63] used a metal foil as substrate for the black-painted absorber. A definite improvement is due to J. Clarke, G. I. Hoffer, P. L. Richards [64] who used a thin low heat capacity dielectric substrate for the metal foil and used a bismuth film absorber instead of the black paint. 

The present chapter reviews recent research efforts aimed at developing new devices for in situ and on-site electrochemical stripping analysis of trace metals. It is not a comprehensive review, but rather focuses on new tools for decentralized metal testing, including remotely deployed submersible stripping probes, hand-held metal analyzers coupled with disposable microfabricated strips, and newly developed green bismuth film sensors. 

Bismuth-film electrodes (BiFEs), consisting of a thin bismuth-film deposited on a suitable substrate, have been shown to offer comparable performance to MFEs in ASY heavy metals determination [17]. The remarkable stripping performance of BiFE can be due to the binary and multi-component fusing alloys formation of bismuth with metals like lead and cadmium [18]. Besides the attractive characteristics of BiFE, the low toxicity of bismuth makes it an alternative material to mercury in terms of trace-metal determination. Various substrates for bismuth-film formation are reported. Bismuth film was prepared by electrodeposition onto the micro disc by applying an in situ electroplating procedure [19]. Bismuth deposition onto gold [20], carbon paste [21], or glassy carbon [22-24] electrodes have been reported to display an... 

The stripping performances of Bi film on glassy carbon or carbon fiber substrates were examined very carefully by Wang et al. [17]. In addition to these materials, GECE (combined with bismuth film), a very easy to prepare and low-cost electrode, can also be used successfully for simultaneous stripping analysis of cadmium and lead. Zinc was also tried to be detected simultaneously with lead and cadmium but it was not possible to obtain undistorted and linearly increased peaks. The poor response to zinc can be probably attributed to the preferable accumulation of Bi on GECE rather than of Zn which is a result of the competition of these two metals for the GECE surface sites as also observed in other works [18]. 

R.O. Kadara and I.E. Tothill, Stripping chronopotentiometric measurements of lead(II) and cadmium(II) in soils extracts and wastewaters using a bismuth film screen-printed electrode assembly, Anal. Bioanal. Chem., 378 (2004) 770-775. 

Other metals, such as copper, nickel, or silver, have been used as electrode materials in connection with specific applications, such as the detection of amino acids or carbohydrates in alkaline media (copper and nickel) and cyanide or sulfur compounds (silver). Unlike platinum or gold electrodes, these electrodes offer a stable response for carbohydrates at constant potentials, through the formation of high-valence oxyhydroxide species formed in situ on the surface and believed to act as redox mediators (40,41). Bismuth film electrodes (preplated or in situ plated ones) have been shown to be an attractive alternative to mercury films used for stripping voltammetry of trace metals (42,43). Alloy electrodes (e.g., platinum-ruthenium, nickel-titanium) are also being used for addressing adsorption or corrosion effects of one of their components. The bifunctional catalytic mechanism of alloy electrodes (such as Pt-Ru or Pt-Sn ones) has been particularly useful for fuel cell applications (44). 

Arribas, A. S., Bermejo, E., Chicharro, M. and Zapardiel, A. (2006), Voltammetric detection of the herbicide metamitron at a bismuth film electrode in nondeaerated solution. Electroanalysis, 18(23) 2331-2336. 

Guzsvany, V., Kaddar, M., Gaal, F., Bjelica, L. and Toth, K. (2006), Bismuth film electrode for the cathodic electrochemical determination of thiamethoxam. Electroanalysis, 18(13-14) 1363-1371. 

Hutton, E. A., Ogorevc, B., Hocevar, S. B. and Smyth, M. R. (2006), Bismuth film microelectrode for direct voltammetric measurement of trace cobalt and nickel in some simulated and real body fluid samples. Anal. Chim. Acta, 557(1-2) 57-63. 

Kefala, G. and Economou, A. (2006), Polymer-coated bismuth film electrodes for the determination of trace metals by sequential-injection analysis/anodic stripping voltammetry. Anal. Chim. Acta, 576(2) 283-289. 

Different versions of stripping analysis have been successfully employed in connection to bismuth-film electrodes. While most early studies have been devoted to conventional stripping-voltammetric measurements, recent activity expanded the scope of bismuth elec-... 

K. Nakajima, T. Sakurai, G. E. Thayer, and R. M. Tromp, Thin bismuth film as a template for pentacene growth, Appl. Phys. Lett 86(7), 073109 (2005). 

The synthesis of fluorinated, volatile bismuth )3-diketonates for MOCVD was reported in a recent submission by Sievers et al. [243]. Bi(fod),i was isolated and characterized to be sufficiently volatile for CVD growth of bismuth films although no BSCCO film growth has yet been demonstrated. This report also provides an excellent survey of volatile bismuth metal-organic and organometallic precursor chemistry. 

A study on operational parameters for advanced use of bismuth film electrode in anodic stripping voltammetry. Electroanalysis 14(24) 1707-1712. 

R. Suhrmann (Technical University of Hanover) According to conductivity and photoelectric measurements, the first step in the oxidation of bismuth is the formation of 02 ions. At low temperatures (90°K) and low pressures (10 mm. Hg), the resistance of thin bismuth films and the work function at first decrease suddenly and then gradually increase because of the decomposition of the O2 molecules into 0 atoms. 

Arsenic, Antimony and Bismuth films can be deposited by hydrogen reduction of their volatilized chlorides [175]. The hydrogen reduction process is best carried out with the trichlorides. These materials are commercially available in grades of sufficient purity for most coating work. The chloride vapourization temperatures and the required substrate temperatures for deposition are as follows ... 

Kadara R. O. and Tothill I. E., Resolving the copper interference effect on the stripping chronopotentiometric response of lead (11) obtained at bismuth film screen-printed electrode, Talanta, 66, 1089-1093, 2005. 

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