Accession Number : AD0017925


Title :   SOLID SOLUTION EQUILIBRIA IN THE ZIRCONIUM-HYDROGEN SYSTEM


Corporate Author : ILLINOIS INST OF TECH CHICAGO


Personal Author(s) : Edwards, Riki K ; Levesque, P ; Cubicciotti, D


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/017925.pdf


Report Date : Aug 1953


Pagination or Media Count : 25


Abstract : H solubility in Zr was determined as a function of temperature and H pressure from 600 deg to 900 deg C. The Zr wire (0,015-in. diam) contained Hf 2. 5-3.0, Fe 0.04, O 0.03, and N o.01%. The commercial H was purified by passing over shredded 5% platinized asbestos heated to 225 deg C. and through a trap at liquid-N temperature. The H solubilities at 1 atm decreased from 65.9 to 51.6 at.-% as the temperature increased from 600 deg to 900 deg C. Partial molal heats and entropies of solutions for molecular H in Zr-H solid solutions were - 39.6 kcal/mol and from -30.2 to -36.4 cal/mol/deg, respectively, from 39.4 to 62.0 at.-% H. The equilibrium-H pressures for different H compositions and temperatures are tabulated. Isothermal pressure-volume curves, isothermal pressure-composition log plots, partial phase diagram of the Zr-H system, and pressure-temperature curves for concentrations from 39.4 to 63.1 at.-% H, are presented. The binary-phase diagram was correlated with previous x-ray work with the system. The phase diagram indicated a new phase (delta) between 59.4 and 61. 0 at.-% H, and the Zr-rich boundary (delta-phase) is invariant with the temperature. The delta-phase appeared to be separated from the epsilon-phase by a narrow 2-phase field which is indirectly established. The boundary compositions were from 49.0 to 52.2 and from 58.9 to 59.6 at.-% for (alpha + delta) and (beta + delta) 2-phase fields, respectively, and temperatures from 700 deg to 875 deg C. Solubilities for a H pressure of 1 atm were about 10% higher than those previously measured.


Descriptors :   *SOLID SOLUTIONS , WIRE , PHASE DIAGRAMS , ENTROPY , X RAYS


Subject Categories : Physical Chemistry


Distribution Statement : APPROVED FOR PUBLIC RELEASE