Co–Cu phases

4 phases (tier A 3, liquid 1); 3 stable in a calculated diagram. Structure types are assigned only when the stored evidence supports an assignment under the stated tier rules (tier A: standard phase name; tier B: unique Materials Project + OQMD on-hull match, DFT-supported; tier C: one structure stated by the assessment's crystallographic table, assessor-stated); other phases list candidates and are marked needs_review. Stability is from phase diagrams calculated with pycalphad from the SGTE binary collection (evidence class: model).

Data: interactive registry · full JSON · Co–Cu system page · Markdown · field reference

Phases of the Co–Cu system (4)
Phase	Structure	Basis	Stability (calculated)	Literature values	TDB models
BCC_A2 phase:co-cu:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	not stable in 4 calculated diagram(s)	0	4
FCC_A1 phase:co-cu:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 4 of 4 calculated diagram(s): 300–1877.99 K, x(Cu) 0–1	12	4
HCP_A3 phase:co-cu:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	stable in 4 of 4 calculated diagram(s): 300–1359.98 K, x(Cu) 0–0.00404	5	4
LIQUID phase:co-cu:liquid	liquid	liquid	stable in 4 of 4 calculated diagram(s): 300.27–2500 K, x(Cu) 0–1	59	4

BCC_A2 (Co–Cu)

Id: phase:co-cu:bcc-a2; status assigned
Structure: W · A2 · cI2 · Im-3m (229); type st:a2-w-ci2; tier A: standard phase name; confidence high
Stability: not stable in 4 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (5): corpus: corpus:phase:co-cu:bcc-a2
tdb: tdb:CoCu-00Kub-LB.tdb:BCC_A2, tdb:CoCu-06Pal.tdb:BCC_A2, tdb:CoCu-80Has.tdb:BCC_A2, tdb:CoCu-97Oht.tdb:BCC_A2

TDB models of BCC_A2 (4): PHASE and CONSTITUENT statements as written

CoCu-00Kub-LB.tdb: BCC_A2, type code %B, sha256 e190588a17897dcb…

37: PHASE BCC_A2 %B 2 1 3 !
38: CONST BCC_A2 : CO CU : VA : !

CoCu-06Pal.tdb: BCC_A2, type code %B, sha256 e6f9f7cd2524034b…

30: PHASE BCC_A2 %B 2 1 3 !
31: CONST BCC_A2 : CO CU : VA : !

CoCu-80Has.tdb: BCC_A2, type code %B, sha256 aab8a56c0d106053…

33: PHASE BCC_A2 %B 2 1 3 !
34: CONST BCC_A2 : CO CU : VA : !

CoCu-97Oht.tdb: BCC_A2, type code %B, sha256 dadbec645d9a2e07…

35: PHASE BCC_A2 %B 2 1 3 !
36: CONST BCC_A2 : CO CU : VA : !

Example references (4 of 4; assessments first):

doi:10.1016/0364-5916(80)90026-7 Mitsuhiro Hasebe, Taiji Nishizawa, Calculation of phase diagrams of the iron-copper and cobalt-copper systems, Calphad 4, 83-100 (1980).
assessment that models this phase
doi:10.1016/j.calphad.2005.10.007 Mauro Palumbo, Stefano Curiotto, Livio Battezzati, Thermodynamic analysis of the stable and metastable Co–Cu and Co–Cu–Fe phase diagrams, Calphad 30, 171-178 (2006).
assessment that models this phase
doi:10.1361/105497100770340165 Jaroslav Kubišta, Jan Vřešt’ál, Thermodynamics of the liquid Co-Cu system and calculation of phase diagram, JPE 21, 125-129 (2000).
assessment that models this phase
doi:10.2355/isijinternational.37.207 Hiroshi Ohtani, Hisashi Suda, Kiyohito Ishida, Effects of Cu and Other Tramp Elements on Steel Properties. Solid/Liquid Equilibria in Fe-Cu Based Ternary Systems., ISIJ International 37, 207-216 (1997).
assessment that models this phase

FCC_A1 (Co–Cu)

Id: phase:co-cu:fcc-a1; status assigned
Structure: Cu · A1 · cF4 · Fm-3m (225); type st:a1-cu-cf4; tier A: standard phase name; confidence high
Stability: stable in 4 of 4 calculated diagram(s): 300–1877.99 K, x(Cu) 0–1
Literature: 12 values (12 accepted) from 1 papers
Interactive: phase registry entry

Names (8): corpus: corpus:phase:co-cu:fcc-a1
paper: paper:10.1007/s11106-007-0013-9:(Cu), paper:10.1007/s11106-007-0013-9:(αCo), paper:10.1007/s11106-007-0013-9:(αCu)
tdb: tdb:CoCu-00Kub-LB.tdb:FCC_A1, tdb:CoCu-06Pal.tdb:FCC_A1, tdb:CoCu-80Has.tdb:FCC_A1, tdb:CoCu-97Oht.tdb:FCC_A1

TDB models of FCC_A1 (4): PHASE and CONSTITUENT statements as written

CoCu-00Kub-LB.tdb: FCC_A1, type code %A, sha256 e190588a17897dcb…

32: PHASE FCC_A1 %A 2 1 1 !
33: CONST FCC_A1 : CO% CU% : VA : !

CoCu-06Pal.tdb: FCC_A1, type code %A, sha256 e6f9f7cd2524034b…

25: PHASE FCC_A1 %A 2 1 1 !
26: CONST FCC_A1 : CO% CU% : VA : !

CoCu-80Has.tdb: FCC_A1, type code %A, sha256 aab8a56c0d106053…

28: PHASE FCC_A1 %A 2 1 1 !
29: CONST FCC_A1 : CO% CU% : VA : !

CoCu-97Oht.tdb: FCC_A1, type code %A, sha256 dadbec645d9a2e07…

30: PHASE FCC_A1 %A 2 1 1 !
31: CONST FCC_A1 : CO% CU% : VA : !

Example references (5 of 5; assessments first):

doi:10.1016/0364-5916(80)90026-7 Mitsuhiro Hasebe, Taiji Nishizawa, Calculation of phase diagrams of the iron-copper and cobalt-copper systems, Calphad 4, 83-100 (1980).
assessment that models this phase
doi:10.1016/j.calphad.2005.10.007 Mauro Palumbo, Stefano Curiotto, Livio Battezzati, Thermodynamic analysis of the stable and metastable Co–Cu and Co–Cu–Fe phase diagrams, Calphad 30, 171-178 (2006).
assessment that models this phase
doi:10.1361/105497100770340165 Jaroslav Kubišta, Jan Vřešt’ál, Thermodynamics of the liquid Co-Cu system and calculation of phase diagram, JPE 21, 125-129 (2000).
assessment that models this phase
doi:10.2355/isijinternational.37.207 Hiroshi Ohtani, Hisashi Suda, Kiyohito Ishida, Effects of Cu and Other Tramp Elements on Steel Properties. Solid/Liquid Equilibria in Fe-Cu Based Ternary Systems., ISIJ International 37, 207-216 (1997).
assessment that models this phase
doi:10.1007/s11106-007-0013-9 M. A. Turchanin, P. G. Agraval, Phase equilibria and thermodynamics of binary copper systems with 3d-metals. V. Copper-cobalt system, Powder Metall Met Ceram 46, 77-89 (2007).
reports values for this phase

HCP_A3 (Co–Cu)

Id: phase:co-cu:hcp-a3; status assigned
Structure: Mg · A3 · hP2 · P6_3/mmc (194); type st:a3-mg-hp2; tier A: standard phase name; confidence high
Stability: stable in 4 of 4 calculated diagram(s): 300–1359.98 K, x(Cu) 0–0.00404
Literature: 5 values (5 accepted) from 1 papers
Interactive: phase registry entry

Names (6): corpus: corpus:phase:co-cu:hcp-a3
paper: paper:10.1007/s11106-007-0013-9:(εCo)
tdb: tdb:CoCu-00Kub-LB.tdb:HCP_A3, tdb:CoCu-06Pal.tdb:HCP_A3, tdb:CoCu-80Has.tdb:HCP_A3, tdb:CoCu-97Oht.tdb:HCP_A3

TDB models of HCP_A3 (4): PHASE and CONSTITUENT statements as written

CoCu-00Kub-LB.tdb: HCP_A3, type code %A, sha256 e190588a17897dcb…

42: PHASE HCP_A3 %A 2 1 0.5 !
43: CONST HCP_A3 : CO% CU : VA : !

CoCu-06Pal.tdb: HCP_A3, type code %A, sha256 e6f9f7cd2524034b…

35: PHASE HCP_A3 %A 2 1 0.5 !
36: CONST HCP_A3 : CO% CU : VA : !

CoCu-80Has.tdb: HCP_A3, type code %A, sha256 aab8a56c0d106053…

38: PHASE HCP_A3 %A 2 1 0.5 !
39: CONST HCP_A3 : CO% CU : VA : !

CoCu-97Oht.tdb: HCP_A3, type code %A, sha256 dadbec645d9a2e07…

40: PHASE HCP_A3 %A 2 1 0.5 !
41: CONST HCP_A3 : CO% CU : VA : !

Example references (5 of 5; assessments first):

doi:10.1016/0364-5916(80)90026-7 Mitsuhiro Hasebe, Taiji Nishizawa, Calculation of phase diagrams of the iron-copper and cobalt-copper systems, Calphad 4, 83-100 (1980).
assessment that models this phase
doi:10.1016/j.calphad.2005.10.007 Mauro Palumbo, Stefano Curiotto, Livio Battezzati, Thermodynamic analysis of the stable and metastable Co–Cu and Co–Cu–Fe phase diagrams, Calphad 30, 171-178 (2006).
assessment that models this phase
doi:10.1361/105497100770340165 Jaroslav Kubišta, Jan Vřešt’ál, Thermodynamics of the liquid Co-Cu system and calculation of phase diagram, JPE 21, 125-129 (2000).
assessment that models this phase
doi:10.2355/isijinternational.37.207 Hiroshi Ohtani, Hisashi Suda, Kiyohito Ishida, Effects of Cu and Other Tramp Elements on Steel Properties. Solid/Liquid Equilibria in Fe-Cu Based Ternary Systems., ISIJ International 37, 207-216 (1997).
assessment that models this phase
doi:10.1007/s11106-007-0013-9 M. A. Turchanin, P. G. Agraval, Phase equilibria and thermodynamics of binary copper systems with 3d-metals. V. Copper-cobalt system, Powder Metall Met Ceram 46, 77-89 (2007).
reports values for this phase

LIQUID (Co–Cu)

Id: phase:co-cu:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 4 of 4 calculated diagram(s): 300.27–2500 K, x(Cu) 0–1
Literature: 59 values (59 accepted) from 2 papers
Interactive: phase registry entry

Names (7): corpus: corpus:phase:co-cu:liquid
paper: paper:10.1007/s11106-007-0013-9:L, paper:10.1361/105497100770340165:liquid
tdb: tdb:CoCu-00Kub-LB.tdb:LIQUID, tdb:CoCu-06Pal.tdb:LIQUID, tdb:CoCu-80Has.tdb:LIQUID, tdb:CoCu-97Oht.tdb:LIQUID

TDB models of LIQUID (4): PHASE and CONSTITUENT statements as written

CoCu-00Kub-LB.tdb: LIQUID, type code %, sha256 e190588a17897dcb…

27: PHASE LIQUID:L % 1 1 !
28: CONST LIQUID:L : CO CU : !

CoCu-06Pal.tdb: LIQUID, type code %, sha256 e6f9f7cd2524034b…

20: PHASE LIQUID:L % 1 1 !
21: CONST LIQUID:L : CO CU : !

CoCu-80Has.tdb: LIQUID, type code %, sha256 aab8a56c0d106053…

23: PHASE LIQUID:L % 1 1 !
24: CONST LIQUID:L : CO CU : !

CoCu-97Oht.tdb: LIQUID, type code %, sha256 dadbec645d9a2e07…

25: PHASE LIQUID:L % 1 1 !
26: CONST LIQUID:L : CO CU : !

Example references (5 of 5; assessments first):

doi:10.1361/105497100770340165 Jaroslav Kubišta, Jan Vřešt’ál, Thermodynamics of the liquid Co-Cu system and calculation of phase diagram, JPE 21, 125-129 (2000).
assessment that models this phase; reports values for this phase
doi:10.1016/0364-5916(80)90026-7 Mitsuhiro Hasebe, Taiji Nishizawa, Calculation of phase diagrams of the iron-copper and cobalt-copper systems, Calphad 4, 83-100 (1980).
assessment that models this phase
doi:10.1016/j.calphad.2005.10.007 Mauro Palumbo, Stefano Curiotto, Livio Battezzati, Thermodynamic analysis of the stable and metastable Co–Cu and Co–Cu–Fe phase diagrams, Calphad 30, 171-178 (2006).
assessment that models this phase
doi:10.2355/isijinternational.37.207 Hiroshi Ohtani, Hisashi Suda, Kiyohito Ishida, Effects of Cu and Other Tramp Elements on Steel Properties. Solid/Liquid Equilibria in Fe-Cu Based Ternary Systems., ISIJ International 37, 207-216 (1997).
assessment that models this phase
doi:10.1007/s11106-007-0013-9 M. A. Turchanin, P. G. Agraval, Phase equilibria and thermodynamics of binary copper systems with 3d-metals. V. Copper-cobalt system, Powder Metall Met Ceram 46, 77-89 (2007).
reports values for this phase

Please cite

R. Arróyave, J. Saal, D. Shin, ORCHID-Registry: phase registry of binary systems (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735970
R. Arróyave, J. Saal, D. Shin, ORCHID data: umbrella record of the ORCHID datasets (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23736065

Also cite B. Hallstedt, The SGTE collection of binary datasets, Calphad 89 (2025) 102833, https://doi.org/10.1016/j.calphad.2025.102833 (CC BY 4.0), and the original assessment named in each file; A. Jain et al., The Materials Project: A materials genome approach to accelerating materials innovation, APL Materials 1 (2013) 011002, https://doi.org/10.1063/1.4812323 (CC BY 4.0); J. E. Saal et al., JOM 65 (2013) 1501, https://doi.org/10.1007/s11837-013-0755-4 and S. Kirklin et al., npj Comput. Mater. 1 (2015) 15010, https://doi.org/10.1038/npjcompumats.2015.10 (CC BY 4.0); the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work). Version 1, machine-extracted: values were read by language-model readers constrained to quote their source and checked automatically, and the release was then audited on the printed pages by adversarial audits, an independent second review of fit-facing records and a preliminary human review of a frozen sample. Flags such as accepted and ESPEI-ready record screening results, not certification; known issues are listed in the release notes.

@misc{orchid_phase_registry_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Registry: phase registry of binary systems}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735970},
  url       = {https://doi.org/10.5281/zenodo.23735970},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_data_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID data: umbrella record of the ORCHID datasets}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23736065},
  url       = {https://doi.org/10.5281/zenodo.23736065},
  note      = {Version 1, machine-extracted}
}