Degassing of metals

H. Stephan, W. Pietsch, H. Ettl, and H. Aichert, Degassing of metal powders and the filling of degassed powders into capsules for the manufacturing of ingots and discs. Proc. Int l Powder Metallurgy Conf Florence, Italy (1982), 179-191. 

Degassing of metal powders and the filling of degassed powders into capsules for the manufacturing of ingots and discs. 

Many metals take up considerable amounts of nitrogen in solid solution. The engassing and degassing of nitrogen in respect of metals is represented by the equilibrium... 

This mass balance presents the possible links in the biogeochemical food web for various heavy metals. Some items may be neglected, like degassing of Pb, Cd, Cu and Zn metals. However, this process is of crucial importance for mercury (see Section 3.2). The output of the heavy metals with soil erosion may also be neglected. After elimination of these processes, the simplified following equation is workable. The sum of inputs by deposition, fertilizing, and waste and rubbish as fertilizer stands as the term Critical Load . 

Plotted curves illustrating this relation, Fig. 5, resemble very much the curves of Fig. 3. Consequently, one cannot infer from a measured intensity or energy saturation curve reliable values of molecular data without additional information, as for instance an independent measurement of ksr Another possibility is a measurement of the temporal characteristics of the bleaching as demonstrated in an experiment by Hercher et al. 14>. These authors bleached a thoroughly degassed solution of metal-free phthalocyanine in 1-chloronaphthalene by a ruby laser pulse (694.3 nm) of about 59 nsec pulse width. At the same time they measured the absorption at 632.8 nm using a He-Ne-laser, and the result of this measurement is shown in Fig. 6. It clearly demonstrates that the sample was almost completely bleached even before the laser pulse reached its maximum intensity, and that almost all of the molecules were stored in the triplet state because the transmission did not decrease with the fall of the laser intensity for at least 100 nsec. A small residual absorption indicates triplet-triplet absorption. 

Nonlinear and dynamic models of desorption are used in the sequel. Mathematical justification of the boundary-value problems for the TDS-degassing method of metal saturated with hydrogen is given in [6,7]. The work [4] was a starting point of the results presented here. Algorithm of parameter identification for the model of hydrogen permeability of metals for the concentration pulses method [5] is presented in [8],... 

If a gauge is outgassed at too high a pressure, a layer of metal (from the electrodes) may be deposited outside the gauge envelope (some controllers prevent degassing at too high a pressure). This condition can cause the insulation to become leaky. A temporary solution can be achieved by grounding the electrical... 

The method in brief is to suspend a thin sheet of metal or solid from the beam of a very sensitive, quartz beam microbalance operating in an all glass or ceramic ware vacuum system. The weight change of the specimen is followed continuously as various operations are performed upon it. When applied to the oxidation of metals these operations include evacuation to pressures of 10 6 mm. Hg or lower, degassing, preliminary reduction of the initial oxide film with pure hydrogen, and oxidation of the metal specimen under widely varying conditions of temperature and pressure. 

Hinkley T. K., Lamothe P. J., Wilson S. A., Finnegan D. L., and Gerlach T. M. (1999) Metal emissions from Kilatiea, and a suggested revision of the estimated worldwide metal output by quiescent degassing of volcanoes. Earth Planet. Sci. Lett. 170, 315-325. 

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