Copper–Palladium Phase Diagram

• Published in: Russian journal of inorganic chemistry Vol. 66; no. 6; pp. 891 - 893
• Main Authors: Fedorov, P. P., Shubin, Yu. V., Chernova, E. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.06.2021; Springer Nature B.V
• Subjects: Absolute zero; Chemistry; Chemistry and Materials Science; Composition; Copper; Eutectoid temperature; Face centered cubic lattice; Inorganic Chemistry; Intermetallic phases; Palladium; Phase diagrams; Phase equilibria; Phase transitions; Physicochemical Analysis of Inorganic Systems; Solid solutions; Stoichiometry; Kurnakov phases; intermetallic compounds; third law of thermodynamics; hydrogen-selective membranes; solid solution; ordering
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023621050053

Phase equilibria in the copper–palladium system are extrapolated to absolute zero of temperature subject to the third law of thermodynamics. The continuous solid solution with a FCC structure that crystallizes from melt experiences ordering to yield two intermetallic phases (Kurnakov phases), whose compositions shrink to CuPd and Cu 3 Pd stoichiometries as temperature lowers. As temperature raises, palladium partially occupies copper sites in the intermetallic phases. Ordering obeying a second-order phase transition to yield a phase whose idealized composition may be formulated as Cu 21 Pd 7 . When in a solid state, the system forms an eutectoid at 390°C and 30 at % Pd and two dystectoids with coordinates of 510°C, 15 at % Pd and 600°C, 40 at % Pd.