Technology thermodynamic stability

Electroless deposition should not be confused with metal displacement reactions, which are often known as cementation or immersion plating processes. In the latter, the less noble metal dissolves and eventually becomes coated with a more noble metal, and the deposition process ceases. Coating thicknesses are usually < 1 pm, and tend to be less continuous than coatings obtained by other methods. A well-known example of an immersion plating process that has technological applications is the deposition of Sn on Cu [17] here a strong complexant for Cu(I), such as thiourea, forces the Cu(I)/Cu couple cathodic with respect to the Sn(II)/Sn couple, thereby increasing the thermodynamic stability in solution of thiourea-complexed Cu(I) relative to Sn(II). 

Stoner, M.R. Dale, D.A. Gualfetti, P.J. Becker, T. Manning, M.C. Carpenter, J.F. Randolph, T.W. Protease autolysis in heavy-duty liquid detergent formulations Effects of thermodynamic stabilizers and protease inhibitors. Enzyme and Microbial Technology 2004, 34, 114—125. 

Thermodynamic stability is generally provided for noble metals in most media as their oxidation potential is more anodic than the reduction potential of species commonly occurring in the surroimding phase. However, for many materials of technological and industrial importance this is not the ease. 

One of the first assumptions in our economic considerations was that all the technological challenges were met. This remains, at the moment of writing, uncertain. In the above discussion, a number of issues have passed, such as sealing technology, thermodynamic phase stability of the cubic perovskite versus brownmillerite, and kinetic demixing. In relation to this, we have not mentioned creep resistance as yet. For SCF, this was shown to be very low [40], which is likely to be the case for BSCF as well. 

In the case of micro-ho lates fabrication using micromachining technology, we have a more complicated situation because, as well as the thermodynamic stability of the materials used, we need to take into account the compatibility of these materials with silicon technology. A more detailed analysis of electrode materials acceptable for micro-hotplates fabrication was carried out by Furjes et al. (2002). Materials acceptable for realization of micro-hotplates are presented in Table 9.1. 

To avoid catalytic interaction of the analyte with a heater made of noble metal, the films are frequently coated with a thin, chemically inert layer of SiO. Such passivation very often serves as a support for further functional layers in top-down microelectronic technologies. It should be noted that the passivation of electrode materials allows a reduction in requirements relating to their thermodynamic stability. In particular, the indicated approach is used in micro-hotplate fabrication. As a result most micro-hotplate designers consider polycrystalline silicon doped with boron or phosphorus impurities to be a very appropriate material for making heaters and temperature sensors because, with capsulation covering, it is stable up to 1,000 °C (Panchapakesan et al. 2001 Hwang... 

Calculation, thermodynamic optimization of phase diagrams. The knowledge of phase equilibria, phase stability, phase transformations is an important reference point in the description and understanding of the fundamental properties of the alloys and of their possible technological applications. This interest has promoted a multi-disciplinary and multi-national effort dedicated not only to experimental methods, but also to techniques of optimization, calculation and prediction of... 

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