Np–Zr system

15 accepted literature values from 1 paper(s) (experimental 8, model 7); 4 calculated phase diagram(s). 4 further extracted value(s) not accepted by the reader-agreement checks are only in the JSON/CSV.

Data: JSON · CSV · interactive explorer · interactive phase diagram · phases (8) · papers (bibliography) · Markdown

Accepted values by evidence class
Evidence class	Values
experimental	8
model	7

Accepted values by property group
Property group	Values
invariant reaction	14
phase transition	1

Calculated phase diagrams

Binary phase diagrams calculated with pycalphad 0.11.2 from the SGTE binary collection (Hallstedt 2025, CC BY 4.0). Evidence class: model.

Assessments with a calculated phase diagram
TDB file	Assessment	SHA-256	Links
NpZr-10Kur.tdb	M. Kurata, IOP Conf. Ser.: Mater. Sci. Eng., 9, 012023(2010).	`c70b656655da30f93f51f752cf8cf795b1cbf583ddb2e828b545c3522d1e6302`	viewer · TDB · JSON
NpZr-11Baj.tdb	S. Bajaj, A. Garay, A. Landa, P. Soderlind, P. Turchi, R. Arroyave, J. Nucl. Mater., 409, 1-8(2011). doi:10.1016/j.jnucmat.2010.10.085	`ce3d595af559b9dc5c4047e7ea6ac093436ac3db25d8d97fbb30a53ad87b4f80`	viewer · TDB · JSON
NpZr-14Xio.tdb	W. Xiong, W. Xie, D. Morgan, J. Nuclear Mater., 452, 569-77(2014). doi:10.1016/j.jnucmat.2014.06.023	`a50b3a238908cb6b6a3d28d3247dfe366f16323d04a10beee6621a006cf063b3`	viewer · TDB · JSON
NpZr-18Xie.tdb	W. Xie, D. Morgan, Comput. Mater. Sci., 143, 505-14(2018). doi:10.1016/j.commatsci.2017.11.042	`df1afba7ad73bcfc13ba1ba01191e9acd268555f061c319319ebdf72a453bfa6`	viewer · TDB · JSON

Calculated three-phase invariants (model, mole fraction of the second component)
TDB file	T (K)	Phases at the invariant
NpZr-10Kur.tdb	867.03	BCC_A2 (x(Zr) 0.79933) + UZR2_DELTA (x(Zr) 0.82373) + HCP_A3 (x(Zr) 0.9756)
NpZr-10Kur.tdb	695.13	TETRAG_AD (x(Zr) 0.01622) + BCC_A2 (x(Zr) 0.13323) + UZR2_DELTA (x(Zr) 0.6451)
NpZr-10Kur.tdb	600	TETRAG_AD (x(Zr) 0.0063) + NP4ZR_THETA (x(Zr) 0.2) + UZR2_DELTA (x(Zr) 0.64754)
NpZr-10Kur.tdb	555.03	TETRAG_AD (x(Zr) 0.00227) + ORTHO_AC (x(Zr) 0.00227) + NP4ZR_THETA (x(Zr) 0.2)
NpZr-11Baj.tdb	881.96	BCC_A2#2 (x(Zr) 0.07828) + LIQUID (x(Zr) 0.082) + BCC_A2 (x(Zr) 0.84738)
NpZr-11Baj.tdb	852.33	BCC_A2#2 (x(Zr) 0.04169) + UZR2_DELTA (x(Zr) 0.72687) + BCC_A2 (x(Zr) 0.8625)
NpZr-11Baj.tdb	838.52	TETRAG_AD (x(Zr) 0.02097) + BCC_A2 (x(Zr) 0.02829) + UZR2_DELTA (x(Zr) 0.71499)
NpZr-11Baj.tdb	585.33	TETRAG_AD (x(Zr) 0.01741) + NP4ZR_THETA (x(Zr) 0.2) + UZR2_DELTA (x(Zr) 0.63512)
NpZr-11Baj.tdb	551.48	ORTHO_AC (x(Zr) 0.00585) + TETRAG_AD (x(Zr) 0.01268) + NP4ZR_THETA (x(Zr) 0.2)
NpZr-14Xio.tdb	909.95	BCC_A2#2 (x(Zr) 0.11238) + LIQUID (x(Zr) 0.12178) + BCC_A2 (x(Zr) 0.66337)
NpZr-14Xio.tdb	846.48	BCC_A2 (x(Zr) 0.08694) + BCC_A2#2 (x(Zr) 0.7083) + HCP_A3 (x(Zr) 0.93672)
NpZr-14Xio.tdb	823.48	BCC_A2 (x(Zr) 0.07382) + UZR2_DELTA (x(Zr) 0.76625) + HCP_A3 (x(Zr) 0.93923)
NpZr-14Xio.tdb	794.37	TETRAG_AD (x(Zr) 0.01271) + BCC_A2 (x(Zr) 0.05821) + UZR2_DELTA (x(Zr) 0.69346)
NpZr-14Xio.tdb	579.6	TETRAG_AD (x(Zr) 0.00205) + NP4ZR_THETA (x(Zr) 0.2) + UZR2_DELTA (x(Zr) 0.65643)
NpZr-14Xio.tdb	554.34	ORTHO_AC (x(Zr) 0) + TETRAG_AD (x(Zr) 0.00127) + NP4ZR_THETA (x(Zr) 0.2)
NpZr-14Xio.tdb	554.34	ORTHO_AC (x(Zr) 0) + TETRAG_AD (x(Zr) 0.00127) + NP4ZR_THETA (x(Zr) 0.2)
NpZr-18Xie.tdb	909.95	BCC_A2#2 (x(Zr) 0.11238) + LIQUID (x(Zr) 0.12178) + BCC_A2 (x(Zr) 0.66337)
NpZr-18Xie.tdb	846.48	BCC_A2 (x(Zr) 0.08694) + BCC_A2#2 (x(Zr) 0.7083) + HCP_A3 (x(Zr) 0.93672)
NpZr-18Xie.tdb	823.06	BCC_A2 (x(Zr) 0.07361) + UZR2_DELTA (x(Zr) 0.76891) + HCP_A3 (x(Zr) 0.93927)
NpZr-18Xie.tdb	791.9	TETRAG_AD (x(Zr) 0.01012) + BCC_A2 (x(Zr) 0.05675) + UZR2_DELTA (x(Zr) 0.69105)
NpZr-18Xie.tdb	580.04	TETRAG_AD (x(Zr) 0.00116) + NP4ZR_THETA (x(Zr) 0.2) + UZR2_DELTA (x(Zr) 0.66771)
NpZr-18Xie.tdb	554.66	ORTHO_AC (x(Zr) 0) + TETRAG_AD (x(Zr) 6.800e-4) + NP4ZR_THETA (x(Zr) 0.2)
NpZr-18Xie.tdb	554.66	ORTHO_AC (x(Zr) 0) + TETRAG_AD (x(Zr) 6.700e-4) + NP4ZR_THETA (x(Zr) 0.2)

Convex hulls: Materials Project DFT hull · OQMD DFT hull · CALPHAD hull NpZr-10Kur · CALPHAD hull NpZr-11Baj · CALPHAD hull NpZr-14Xio

Invariant reactions (literature)

Invariant reactions reported in the literature for the Np–Zr system (14)
T (K)	Reaction / phases	Compositions (mole fraction)	Class	Source	Location
903	eutectic: L -> γ-Np + β-Zr	L: Zr 0.15	experimental	[1] Bajaj 2011 cites Okamoto 2000	Table 3, p. 5, row 1 report
883	eutectoid: β-Zr -> γ-Np + α-Zr	β-Zr: Zr 0.83	experimental	[1] Bajaj 2011 cites Okamoto 2000	Table 3, p. 5, row 3 report
882	eutectic: L -> γ-Np + β-Zr	L: Zr 0.08	model	[1] Bajaj 2011	Table 3, p. 5, row 2 report
852.3	eutectoid: β-Zr -> γ-Np + α-Zr	β-Zr: Zr 0.86	model	[1] Bajaj 2011	Table 3, p. 5, row 4 report
852.2	peritectoid: γ-Np + α-Zr -> δ-NpZr2 (Model 1)	γ-Np: Zr 0.73; δ-NpZr2: Zr 0.666667	model	[1] Bajaj 2011	Table 3, p. 5, row 6 report
843.5	peritectoid: γ-Np + α-Zr -> δ-NpZr2 (Model 2)	γ-Np: Zr 0.79; δ-NpZr2: Zr 0.666667	model	[1] Bajaj 2011	Table 3, p. 5, row 8 report
838.5	eutectoid: γ-Np -> β-Np + δ-NpZr2	γ-Np: Zr 0.03; δ-NpZr2: Zr 0.666667	model	[1] Bajaj 2011	Table 3, p. 5, row 10 report
823	peritectoid: γ-Np + α-Zr -> δ-NpZr2 (Model 2)	γ-Np: Zr 0.7; δ-NpZr2: Zr 0.666667	experimental	[1] Bajaj 2011 cites Okamoto 2000	Table 3, p. 5, row 7 report
823	peritectoid: γ-Np + α-Zr -> δ-NpZr2 (Model 1)	γ-Np: Zr 0.7; δ-NpZr2: Zr 0.666667	experimental	[1] Bajaj 2011 cites Okamoto 2000	Table 3, p. 5, row 5 report
803	eutectoid: γ-Np -> β-Np + δ-NpZr2	γ-Np: Zr 0.03; δ-NpZr2: Zr 0.666667	experimental	[1] Bajaj 2011 cites Okamoto 2000	Table 3, p. 5, row 9 report
588	peritectoid: β-Np + δ-NpZr2 -> θ-Np4Zr	δ-NpZr2: Zr 0.666667; θ-Np4Zr: Zr 0.2	experimental	[1] Bajaj 2011 cites Okamoto 2000	Table 3, p. 5, row 11 report
585.5	peritectoid: β-Np + δ-NpZr2 -> θ-Np4Zr	δ-NpZr2: Zr 0.666667; θ-Np4Zr: Zr 0.2	model	[1] Bajaj 2011	Table 3, p. 5, row 12 report
553	eutectoid: β-Np -> α-Np + θ-Np4Zr	β-Np: Zr 0.015; θ-Np4Zr: Zr 0.2	experimental	[1] Bajaj 2011 cites Okamoto 2000	Table 3, p. 5, row 13 report
551	eutectoid: β-Np -> α-Np + θ-Np4Zr	β-Np: Zr 0.015; θ-Np4Zr: Zr 0.2	model	[1] Bajaj 2011	Table 3, p. 5, row 14 report

Other properties

Phase transition (1)

Phase transition, Np–Zr system
Property	Value	T (K)	Phases / composition	Class	Source	Location	Quote
Phase transition	823.15 K	823.15	other	experimental	[1] Bajaj 2011 cites Okamoto 1996 doi	p. 2 report	A decomposition temperature of 550 °C was assigned and it was concluded that this phase formed from c-Np and a-Zr.

Sources

Reporting papers the values were read from (a value cited from another work names that work in its row).

Saurabh Bajaj, Andres Garay, Alexander Landa, Per Söderlind, Patrice Turchi, Raymundo Arróyave, Thermodynamic study of the Np–Zr system, Journal of Nuclear Materials 409, 1-8 (2011). doi:10.1016/j.jnucmat.2010.10.085

Please cite

R. Arróyave, J. Saal, D. Shin, ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature (version 2026.10; Version 1, machine-extracted), Zenodo (2026). doi:10.5281/zenodo.23735569
R. Arróyave, J. Saal, D. Shin, ORCHID-Diagrams: calculated binary phase diagrams (version 2026.10), Zenodo (2026). doi:10.5281/zenodo.23735859
R. Arróyave, J. Saal, D. Shin, ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD) (version 2026.10), Zenodo (2026). doi:10.5281/zenodo.23735891
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 the original source of every value you use (paper_citation / paper_doi, and cited_dois for values the paper cites from earlier work); 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). 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_literature_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Values: thermodynamic and phase-equilibrium values read from the literature}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735569},
  url       = {https://doi.org/10.5281/zenodo.23735569},
  note      = {Version 1, machine-extracted}
}

@misc{orchid_phase_diagrams_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Diagrams: calculated binary phase diagrams}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735859},
  url       = {https://doi.org/10.5281/zenodo.23735859}
}

@misc{orchid_hulls_2026,
  author    = {Arr{\'o}yave, Raymundo and Saal, James and Shin, Dongwon},
  title     = {{ORCHID-Hulls: binary convex hulls (Materials Project, OQMD, assessed CALPHAD)}},
  version   = {2026.10},
  publisher = {Zenodo},
  year      = {2026},
  doi       = {10.5281/zenodo.23735891},
  url       = {https://doi.org/10.5281/zenodo.23735891}
}

@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}
}