On the phase stability of CaCu5-type compounds

Boeije, M.F.J.; Delczeg‐Czirjak, Erna K.; Dijk, N.H. van; Eriksson, Olle; Brück, E.

doi:10.1016/j.jallcom.2017.06.134

Cited by 5 publications

(5 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The DT model achieves competitively high performance (Figure ) and was very fast to develop, taking <15 min to train the data and about 3 h to make predictions on >400000 candidates (or <0.05 s per compound). It makes use of a much smaller number of descriptors (16) that are weighted sums or absolute differences of elemental properties based on position in the periodic table (number of valence electrons n valence , group number n group , and Mendeleev number MN ), radius (Zunger sum of pseudopotential orbital radii r Zunger = r s + r p ), electronegativity (χ Allen ), , bulk density (ρ), and two interesting parameters that were first proposed by Miedema to predict the heats of formation of binary alloys: an adjusted work function ϕ* and the cube root of the average electron density at boundary of Wigner–Seitz cell n WS 1/3 . − In Miedema’s original formulation, the values of ϕ* correlate with electronegativity, so differences in ϕ* measure the degree of electron transfer between two dissimilar metals, whereas differences in n WS 1/3 relate to the gradient of electron density between neighboring atoms and influence properties such as compressibility and bulk modulus . Miedema’s empirical model forms the basis for the estimation of thermodynamic properties, including construction of phase diagrams and evaluating miscibility of metals .…”

Section: Resultsmentioning

confidence: 99%

“…As post-hoc rationalization of these results, the ranges of solid solubility in Cd(Cu 1– x Sb x ) 2 , Cd(Cu 1– x Sn x ) 2 , and Cd(Cu 1– x Zn x ) 2 can be correlated to the relative solubility of Sb, Sn, or Zn in Cu, suggesting that perhaps a simpler model with fewer features could be sufficient to predict their formation. Given that the Miedema model has been previously applied to evaluate the phase stability of related intermetallic compounds, such as CaCu 5 -type phases, using only ϕ* and n WS 1/3 as features, it is interesting to see how it would perform in predicting Laves phases. DT models built with only one or two of these types of features are much less accurate than the full-feature DT model (Table S6).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Ahead by a Century: Discovery of Laves Phases Assisted by Machine Learning

Sikdar,

Roy,

Selvaratnam

et al. 2024

Inorg. Chem.

View full text Add to dashboard Cite

Laves phases AB 2 form the most abundant group of intermetallic compounds, consisting of combinations of larger electropositive metals A with smaller metals B. Many practical applications of Laves phases depend on the ability to tune their physical properties through appropriate substitution of either the A or B component. Although simple geometrical and electronic factors have long been thought to control the formation of Laves phases, no single factor alone can make predictions accurately. Several machine learning models have been developed to discover new Laves phases, including variations caused by solid solubility, using elemental properties solely on the basis of chemical composition. These models were trained on a data set comprising about 3700 entries of experimentally known phases AB 2 with Laves and non-Laves structures. Among these models, a decision tree algorithm gave very good performance (average recall of 95%, precision of 94%, and accuracy of 96% on the test set) by using only a small set of descriptors, the most important of which relates to the electron density at the boundary of the Wigner−Seitz cell for the B component. This model provides guidance for new experiments by making predictions on >400000 candidates very quickly. A chemically unintuitive candidate Cd(Cu 1−x Sb x ) 2 with a limited solid solubility of Sb for Cu was targeted; it was successfully synthesized and confirmed to adopt a cubic MgCu 2 -type Laves structure.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Ahead by a Century: Discovery of Laves Phases Assisted by Machine Learning

Sikdar,

Roy,

Selvaratnam

et al. 2024

Inorg. Chem.

View full text Add to dashboard Cite

show abstract

“…For selected examples in the field of magnetic and hydrogen storage materials as well as on phase stability calculations we refer to recent overviews. [31][32][33]…”

Section: Crystal Chemistrymentioning

confidence: 99%

“…The many non‐stoichiometric compositions (mixing is known for both copper positions of the aristotype; formation of extended homogeneity ranges/solid solutions) listed for the CaCu 5 types entries in the Pearson data base [2] prove this behavior. For selected examples in the field of magnetic and hydrogen storage materials as well as on phase stability calculations we refer to recent overviews [31–33] …”

Section: Crystal Chemistrymentioning

confidence: 99%

APd₂Zn₃ (A=Ca, Sr, Eu) with a CaCu₅ superstructure

Pöttgen

Gerke

Niehaus

et al. 2022

Zeitschrift anorg allge chemie

View full text Add to dashboard Cite

The intermetallic phases APd2Zn3 (A=Ca, Sr, Eu) were synthesized from the elements in sealed niobium ampules in an induction furnace. The phase purity of the samples was checked by powder X‐ray diffraction (Guinier technique). The structures were refined from single crystal X‐ray diffractometer data: YNi2Al3 type (CaCu5 superstructure), P6/mmm, a=936.97(4), c=420.75(2) pm, wR2=0.0206, 259 F2 values, 17 variables for CaPd2Zn3, a=953.63(6), c=425.38(3) pm, wR2=0.0185, 230 F2 values, 17 variables for SrPd2Zn3 and a=948.20(7), c=423.20(3) pm, wR2=0.0209, 228 F2 values, 18 variables for EuPd2.12(1)Zn2.88(1). The europium‐based crystal showed a small homogeneity range through Pd/Zn mixing. The striking structural motifs of the APd2Zn3 phases are Kagome networks formed by the palladium and zinc atoms. The superstructure formation (discussed on the basis of a Bärnighausen tree) results from a different Pd/Zn coloring and a shift of one A position by c/2. The divalent character of europium in EuPd2Zn3 was substantiated by magnetic susceptibility and 151Eu Mössbauer spectroscopic measurements. EuPd2Zn3 orders ferrimagnetically at TC=17.5(5) K. The magnetization behavior at 3 K (two‐step magnetization) confirms the existence of two crystallographically independent europium sites. The 151Eu Mössbauer spectrum at 5 K shows full magnetic hyperfine field splitting (δ=−8.99(4) mm s−1 and BHf=27.7(1) T).

show abstract

“…The A site is usually occupied by La, Ca or rare earth element while Ni, Cu, Co, Pt or Fe fill the B site [59]. AB 5 alloys are known to have a CuCa 5 -type hexagonal crystal structure which normally belongs to space group P6/mmm (#191) [60,61]. Singh et al [62] evaluated the effect of milling MmNi 4:6 Fe 0:4 alloy, where Mm refers to mischmetal, varying the milling period from 10, 20 and 30 min, at a milling speed of 200 rpm.…”

Section: Structural Characteristics Of Mechanically Milled Ab 5 -Type...mentioning

confidence: 99%

A Comprehensive Review on Hydrogen Absorption Behaviour of Metal Alloys Prepared through Mechanical Alloying

Somo

Maponya

Davids

et al. 2020

Metals

View full text Add to dashboard Cite

Hydride-forming alloys are currently considered reliable and suitable hydrogen storage materials because of their relatively high volumetric densities, and reversible H2 absorption/desorption kinetics, with high storage capacity. Nonetheless, their practical use is obstructed by several factors, including deterioration and slow hydrogen absorption/desorption kinetics resulting from the surface chemical action of gas impurities. Lately, common strategies, such as spark plasma sintering, mechanical alloying, melt spinning, surface modification and alloying with other elements have been exploited, in order to overcome kinetic barriers. Through these techniques, improvements in hydriding kinetics has been achieved, however, it is still far from that required in practical application. In this review, we provide a critical overview on the effect of mechanical alloying of various metal hydrides (MHs), ranging from binary hydrides (CaH2, MgH2, etc) to ternary hydrides (examples being Ti-Mn-N and Ca-La-Mg-based systems), that are used in solid-state hydrogen storage, while we also deliver comparative study on how the aforementioned alloy preparation techniques affect H2 absorption/desorption kinetics of different MHs. Comparisons have been made on the resultant material phases attained by mechanical alloying with those of melt spinning and spark plasma sintering techniques. The reaction mechanism, surface modification techniques and hydrogen storage properties of these various MHs were discussed in detail. We also discussed the remaining challenges and proposed some suggestions to the emerging research of MHs. Based on the findings obtained in this review, the combination of two or more compatible techniques, e.g., synthesis of metal alloy materials through mechanical alloying followed by surface modification (metal deposition, metal-metal co-deposition or fluorination), may provide better hydriding kinetics.

show abstract

On the phase stability of CaCu5-type compounds

Cited by 5 publications

References 26 publications

Ahead by a Century: Discovery of Laves Phases Assisted by Machine Learning

Ahead by a Century: Discovery of Laves Phases Assisted by Machine Learning

APd₂Zn₃ (A=Ca, Sr, Eu) with a CaCu₅ superstructure

A Comprehensive Review on Hydrogen Absorption Behaviour of Metal Alloys Prepared through Mechanical Alloying

Contact Info

Product

Resources

About

On the phase stability of CaCu5-type compounds

Cited by 5 publications

References 26 publications

Ahead by a Century: Discovery of Laves Phases Assisted by Machine Learning

Ahead by a Century: Discovery of Laves Phases Assisted by Machine Learning

APd2Zn3 (A=Ca, Sr, Eu) with a CaCu5 superstructure

A Comprehensive Review on Hydrogen Absorption Behaviour of Metal Alloys Prepared through Mechanical Alloying

Contact Info

Product

Resources

About

APd₂Zn₃ (A=Ca, Sr, Eu) with a CaCu₅ superstructure