Document Details
PURL
(819 K)
Title:
Experimental Program - BeO-H20 Reaction
Author(s):
Saul, A. M. [North American Aviation, Inc., Canoga Park, CA (United States). Atomics International Div.]; Potter, N. [North American Aviation, Inc., Canoga Park, CA (United States). Atomics International Div.]
Document Type:
REPORT
Publication Date:
1956 Oct 12
Declassification Date:
1997 Jul 21
Declassification Status:
Declassified
Document Pages:
9 p.
Accession Number:
None
Document Number(s):
NAA-SR-MEMO-1758
Originating Research Org.:
North American Aviation, Inc., Canoga Park, CA (United States). Atomics International Div.
OpenNet Entry Date:
2017 Mar 29
OpenNet Modified Date:
2023 Nov 09
Description/Abstract:
Although BeO has desirable nuclear and physical properties, it reacts readily with water vapor at temperatures above 1250° C to form a volatile compound. The volatilization rate increases with increasing temperature and is too high to be accounted for by the equilibrium vapor pressure of beryllia alone. Measurements by Grossweiner and Seifert on the effect of temperature and the partial pressure of water on the rate of volatilization of beryllia indicate that the increased volatility results from the reaction BeO(s) + H2O(8) → Be(OH)2(g). From their data at 1400° C, ΔH° = 41.5 kcal/mole and ΔF° = 29 kcal/mole. Hence ΔS° = 7.5 entropy units. No heat capacity data are given, so we shall assume that ΔH° does not vary with temperature; ΔF° at 2000° C, then, is available from the relationship ΔF° = ΔH° - TΔS° and is equal to 24.5 kcal. Since all spontaneous processes taking place at constant temperature and pressure are accompanied by a decrease of free energy, one might hastily conclude from. the large positive value of ΔF° that reaction does not proceed spontaneously. However, the product of the reaction, Be(OH)2 is gaseous and is being constantly removed; this allows the reaction to proceed.