Water vapor metastable system

Physico-chemical ways of achieving metastability of the initial system are usually related to changes in temperature, pressure (less often), and composition of solvent [10]. The supersaturation (supercooling) of water vapor is the reason for certain meteorological phenomena (cloud formation). The formation of disperse systems upon changes in temperature is the key for the preparation of all polycrystalline materials in metallurgy. Here control of... 

As a base for the development of these probes, water vapor partial pressure was firstly determined exactly with the help of a galvanic solid-electrolyte cell in the 1, g-equilibrium system H2O-NH3 in the temperature range from 0 to 30 °C [91]. The results were used in the investigation of the decomposition of metastable NH3 at the platinum electrode of a solid-electrolyte cell. It was proved that the NH3 decomposition in the temperature range from 500 to... 

It goes without saying that suspended transformations may also accompany the phase interconversions of anhydrates and solvates. Efflorescence may not occur immediately once the pressure is reduced below the dissociation pressure, but such reactions will always take place upon formation of a suitable nucleus. For instance, it has been known since the time of Michael Faraday that the decahydrate phase of sodium sulfate is unstable with respect to open air, since the vapor pressure of the salt exceeds the vapor pressure of water vapor at room temperature. However, the system only dehydrates upon contact with the anhydrate phase, demonstrating the metastable nature of the decahydrate phase. 

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