Co–Ni phases

6 phases (tier A 4, liquid 1, unresolved_no_candidates 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–Ni system page · Markdown · field reference

Phases of the Co–Ni system (6)
Phase	Structure	Basis	Stability (calculated)	TDB models
BCC_A2 phase:co-ni:bcc-a2	W · A2 · cI2 · Im-3m (229)	tier A: standard phase name	not stable in 2 calculated diagram(s)	2
SIGMA_D8B phase:co-ni:d8b-sigma	sigma-CrFe · D8_b · tP30 · P4_2/mnm (136)	tier A: standard phase name	not stable in 2 calculated diagram(s)	2
DIS_SIG phase:co-ni:dis-sig		unresolved_no_candidates	not stable in 1 calculated diagram(s)	1
FCC_A1 phase:co-ni:fcc-a1	Cu · A1 · cF4 · Fm-3m (225)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–1767.99 K, x(Ni) 0–1	2
HCP_A3 phase:co-ni:hcp-a3	Mg · A3 · hP2 · P6_3/mmc (194)	tier A: standard phase name	stable in 2 of 2 calculated diagram(s): 300–695.44 K, x(Ni) 0–0.29141	2
LIQUID phase:co-ni:liquid	liquid	liquid	stable in 2 of 2 calculated diagram(s): 1728.25–2500 K, x(Ni) 0–1	2

BCC_A2 (Co–Ni)

Id: phase:co-ni: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 2 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:co-ni:bcc-a2
tdb: tdb:CoNi-24Per.tdb:BCC_A2, tdb:CoNi-87Fer-LB.tdb:BCC_A2

TDB models of BCC_A2 (2): PHASE and CONSTITUENT statements as written

CoNi-24Per.tdb: BCC_A2, type code %B, sha256 969df9adb5e23ceb…

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

CoNi-87Fer-LB.tdb: BCC_A2, type code %B, sha256 b0243f66a4c704e5…

32: PHASE BCC_A2 %B 2 1 3 !
33: CONST BCC_A2 : CO NI : VA : !

Example references (2 of 2; assessments first):

doi:10.1007/s11669-023-01079-3 Júlio César Pereira dos Santos, Sean Griesemer, Nathalie Dupin, Ursula R. Kattner, Chuan Liu, Daniela Ivanova et al., Applying the Effective Bond Energy Formalism (EBEF) to Describe the Sigma (σ) Phase in the Co-Cr-Ni-Re System, J. Phase Equilib. Diffus. 45, 330-357 (2024).
assessment that models this phase
doi:10.1515/ijmr-1987-780905 A. Fernandez Guillermet, Z. Metallkd., 78, 639-47(1987).
assessment that models this phase

SIGMA_D8B (Co–Ni)

Id: phase:co-ni:d8b-sigma; status assigned
Structure: sigma-CrFe · D8_b · tP30 · P4_2/mnm (136); type st:d8-b-sigma-crfe-tp30; tier A: standard phase name; confidence high
Caveat: partitioned order/disorder model in CoNi-24Per.tdb also describes the disordered state
Caveat: partitioned order/disorder model in CoNi-87Fer-LB.tdb also describes the disordered state
Stability: not stable in 2 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:co-ni:d8b-sigma
tdb: tdb:CoNi-24Per.tdb:SIGMA_D8B, tdb:CoNi-87Fer-LB.tdb:SIGMA_D8B

TDB models of SIGMA_D8B (2): PHASE and CONSTITUENT statements as written

CoNi-24Per.tdb: SIGMA_D8B, type code %AS, sha256 969df9adb5e23ceb…

48: PHASE SIGMA_D8B %AS 5 2 4 8 8 8 !
49: CONST SIGMA_D8B : CO NI : CO NI : CO NI : CO NI : CO NI : !

CoNi-87Fer-LB.tdb: SIGMA_D8B, type code %, sha256 b0243f66a4c704e5…

42: PHASE SIGMA_D8B % 3 10 4 16 !
43: CONST SIGMA_D8B : CO NI : CO NI : CO NI : !

Example references (2 of 2; assessments first):

doi:10.1007/s11669-023-01079-3 Júlio César Pereira dos Santos, Sean Griesemer, Nathalie Dupin, Ursula R. Kattner, Chuan Liu, Daniela Ivanova et al., Applying the Effective Bond Energy Formalism (EBEF) to Describe the Sigma (σ) Phase in the Co-Cr-Ni-Re System, J. Phase Equilib. Diffus. 45, 330-357 (2024).
assessment that models this phase
doi:10.1515/ijmr-1987-780905 A. Fernandez Guillermet, Z. Metallkd., 78, 639-47(1987).
assessment that models this phase

DIS_SIG (Co–Ni)

Id: phase:co-ni:dis-sig; status unresolved_no_candidates
No structure assigned. Why: name_has_descriptive_tokens:DIS,SIG; no_structure_token
Stability: not stable in 1 calculated diagram(s)
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (2): corpus: corpus:phase:co-ni:dis-sig
tdb: tdb:CoNi-24Per.tdb:DIS_SIG

TDB models of DIS_SIG (1): PHASE and CONSTITUENT statements as written

CoNi-24Per.tdb: DIS_SIG, type code %A, sha256 969df9adb5e23ceb…

43: PHASE DIS_SIG %A 1 1 !
44: CONST DIS_SIG : CO NI : !

Example references (1 of 1; assessments first):

doi:10.1007/s11669-023-01079-3 Júlio César Pereira dos Santos, Sean Griesemer, Nathalie Dupin, Ursula R. Kattner, Chuan Liu, Daniela Ivanova et al., Applying the Effective Bond Energy Formalism (EBEF) to Describe the Sigma (σ) Phase in the Co-Cr-Ni-Re System, J. Phase Equilib. Diffus. 45, 330-357 (2024).
assessment that models this phase

FCC_A1 (Co–Ni)

Id: phase:co-ni: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 2 of 2 calculated diagram(s): 300–1767.99 K, x(Ni) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:co-ni:fcc-a1
tdb: tdb:CoNi-24Per.tdb:FCC_A1, tdb:CoNi-87Fer-LB.tdb:FCC_A1

TDB models of FCC_A1 (2): PHASE and CONSTITUENT statements as written

CoNi-24Per.tdb: FCC_A1, type code %A, sha256 969df9adb5e23ceb…

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

CoNi-87Fer-LB.tdb: FCC_A1, type code %A, sha256 b0243f66a4c704e5…

27: PHASE FCC_A1 %A 2 1 1 !
28: CONST FCC_A1 : CO% NI% : VA : !

Example references (2 of 2; assessments first):

doi:10.1007/s11669-023-01079-3 Júlio César Pereira dos Santos, Sean Griesemer, Nathalie Dupin, Ursula R. Kattner, Chuan Liu, Daniela Ivanova et al., Applying the Effective Bond Energy Formalism (EBEF) to Describe the Sigma (σ) Phase in the Co-Cr-Ni-Re System, J. Phase Equilib. Diffus. 45, 330-357 (2024).
assessment that models this phase
doi:10.1515/ijmr-1987-780905 A. Fernandez Guillermet, Z. Metallkd., 78, 639-47(1987).
assessment that models this phase

HCP_A3 (Co–Ni)

Id: phase:co-ni: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 2 of 2 calculated diagram(s): 300–695.44 K, x(Ni) 0–0.29141
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:co-ni:hcp-a3
tdb: tdb:CoNi-24Per.tdb:HCP_A3, tdb:CoNi-87Fer-LB.tdb:HCP_A3

TDB models of HCP_A3 (2): PHASE and CONSTITUENT statements as written

CoNi-24Per.tdb: HCP_A3, type code %A, sha256 969df9adb5e23ceb…

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

CoNi-87Fer-LB.tdb: HCP_A3, type code %A, sha256 b0243f66a4c704e5…

37: PHASE HCP_A3 %A 2 1 0.5 !
38: CONST HCP_A3 : CO% NI : VA : !

Example references (2 of 2; assessments first):

doi:10.1007/s11669-023-01079-3 Júlio César Pereira dos Santos, Sean Griesemer, Nathalie Dupin, Ursula R. Kattner, Chuan Liu, Daniela Ivanova et al., Applying the Effective Bond Energy Formalism (EBEF) to Describe the Sigma (σ) Phase in the Co-Cr-Ni-Re System, J. Phase Equilib. Diffus. 45, 330-357 (2024).
assessment that models this phase
doi:10.1515/ijmr-1987-780905 A. Fernandez Guillermet, Z. Metallkd., 78, 639-47(1987).
assessment that models this phase

LIQUID (Co–Ni)

Id: phase:co-ni:liquid; status assigned
Structure: liquid; type st:liquid; liquid; confidence high
Stability: stable in 2 of 2 calculated diagram(s): 1728.25–2500 K, x(Ni) 0–1
Literature: 0 values (0 accepted) from 0 papers
Interactive: phase registry entry

Names (3): corpus: corpus:phase:co-ni:liquid
tdb: tdb:CoNi-24Per.tdb:LIQUID, tdb:CoNi-87Fer-LB.tdb:LIQUID

TDB models of LIQUID (2): PHASE and CONSTITUENT statements as written

CoNi-24Per.tdb: LIQUID, type code %, sha256 969df9adb5e23ceb…

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

CoNi-87Fer-LB.tdb: LIQUID, type code %, sha256 b0243f66a4c704e5…

22: PHASE LIQUID:L % 1 1 !
23: CONST LIQUID:L : CO NI : !

Example references (2 of 2; assessments first):

doi:10.1007/s11669-023-01079-3 Júlio César Pereira dos Santos, Sean Griesemer, Nathalie Dupin, Ursula R. Kattner, Chuan Liu, Daniela Ivanova et al., Applying the Effective Bond Energy Formalism (EBEF) to Describe the Sigma (σ) Phase in the Co-Cr-Ni-Re System, J. Phase Equilib. Diffus. 45, 330-357 (2024).
assessment that models this phase
doi:10.1515/ijmr-1987-780905 A. Fernandez Guillermet, Z. Metallkd., 78, 639-47(1987).
assessment that models 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}
}