Reinvestigation of the Ce–Co–Al ternary system: Isothermal section at 973K

Nasri, N.; Gastebois, J.; Pasturel, Mathieu; Belgacem, B.; Péron, Isabelle; Gouttefangeas, Françis; Hassen, R. Ben; Tougait, Olivier; Noël, H.

doi:10.1016/j.jallcom.2014.12.184

Cited by 5 publications

(2 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among the large number of equiatomic CeTX intermetalllics (T = electron-rich transition metal; X = element of the 3rd, 4th or 5th main group) [1][2][3][4][5], CeCoAl [6][7][8][9][10][11][12][13][14], CeCoGa [6,[15][16][17], and CeRuSn [18][19][20][21][22][23][24][25][26][27][28][29] exhibit unusual crystal chemistry. These three intermetallics have the same valence electron count and the same subcell structure which derives from the Bi 2 Pd type [30][31][32], space group C2/m, through an ordering of the cerium and aluminum (gallium, tin) atoms on the bismuth sites.…”

Section: Introductionmentioning

confidence: 99%

Intermediate-valent CeCoAl – a commensurate modulated structure with short Ce–Co distances

Niehaus

Hoffmann

Tencé

et al. 2015

Zeitschrift Für Kristallographie - Crystalline Materials

View full text Add to dashboard Cite

CeCoAl was synthesized by melting of the elements in a sealed niobium tube in an induction furnace. Annealing of the sample gave access to a single phase sample. Its structure was refined on the basis of single-crystal X-ray diffractometer data at different temperatures. Above 271 K CeCoAl crystallizes in its own structure type in the space group C2/m [a = 1107.4(2), b = 440.6(1) and c = 479.6(1) pm, β = 104.6(1)°]. Data obtained at 300 K lead to 511 F 2 values with 20 variables and a residual of [I ≥ 3σ(I)] wR = 0.0539. Below 271 K satellites give rise to the superspace group C2/m(α0γ)00; α = 2/3, γ = 2/5 with a temperature independent q-vector. For the 90 K data (also for 180 and 220 K) the commensurate modulated structure could be refined with 4817 F 2 values, 129 variables and residuals of wR = 0.0347 (main), wR = 0.1927 (satellites 1st order), wR = 0.1541 (satellites 2nd order) and wR = 0.1768 (satellites 3rd order) [a = 1107.5(1), b = 440.3(1) and c = 479.0(1) pm, β = 104.7(1)°]. For the three temperatures only minor variations of the modulation amplitudes are observed. The relation of the low temperature (3+1)D 3a × 5c approximant and the room temperature 3D structure is discussed on the basis of a group-subgroup relation. By investigation of the heat capacity, the phase transition could be identified as a second order one with a transition temperature of 271 K. Magnetic measurements clearly prove the intermediate cerium valence which is in line with the short Ce-Co distances.

show abstract

Section: Introductionmentioning

confidence: 99%

Intermediate-valent CeCoAl – a commensurate modulated structure with short Ce–Co distances

Niehaus

Hoffmann

Tencé

et al. 2015

Zeitschrift Für Kristallographie - Crystalline Materials

View full text Add to dashboard Cite

show abstract

“…The distribution confirmed occurrence of three structural elements: dendrites rich in Co, Al and W ("A"), interdendritic spaces containing only Co, Al and W ("B"), and ternary Ce-Co-Al phases located in the intedendritic region ("C"). Taking into account equlibrium conditions at higher temperatures [23,24], the following ternary phases Ce-Co-Al phases were found: CeCoAl, CeCoAl The further part of studies concerned TG/DTA analysis of the investigated alloys (Fig. 4).…”

Section: Resultsmentioning

confidence: 99%

Archives of Metallurgy and Materials

Migas,

Liptáková,

Moskal

2021

View full text Add to dashboard Cite

The γ/γ′ Co-based alloys are a new class of cobalt superalloys, which are characterized by remarkable high temperature strength owing to strengthening by γ′-Co 3 (Al, X) phases. In this investigation, the effect of cerium addition on oxidation behavior of model Co-Al-W alloys was studied. The introduction of Ce aimed at improvement of the oxidation resistance of γ′-forming Co-based superalloys. The minor additions of cerium (0.1, 0.5 at.%) were added to the base alloy Co-9Al-9W. The alloys were prepared via induction vacuum melting (VIM). Further, a primary microstructure of the alloys was analyzed with particular regard to a segregation of Ce. The thermogravimetric analysis (TG) under non-isothermal conditions was used to preliminary estimate the oxidation behavior of alloys at different temperatures. During experiment, differential thermal analysis (DTA) was performed simultaneously. After this test, cyclic oxidation expermients was carried out at 800°C for 500 h.In as-cast state, Ce segregates to interdendritic areas and forms intermetallic phases. The effect connected with melting of interdendritic precipitates was observed at 1160°C. Ce-containing alloys were less prone of oxide spallation. Moreover, oxidation rate of these alloys substantially decreased after 100h of oxidation, whereas mass of the sample corresponding to base alloy continued to increase.

show abstract

Enthalpies of Mixing in Al−Ce−Co Liquid Alloys

Usenko,

Ivanov,

Kotova

2024

ChemistrySelect

View full text Add to dashboard Cite

The enthalpies of mixing in liquid alloys of the ternary Al−Ce−Co system were determined along four sections (with a constant mole fraction ratio xCe/xCo=0.77/0.23 and xCe/xCo=0.35/0.65 up to xAl=0.2 at 1700 K; with xAl/xCo=0.76/0.24 up to xCe=0.3 and xAl/xCe=0.30/0.70 up to xCo=0.23 at 1823 K) via isoperibolic calorimetry. The enthalpies of mixing in the liquid Al−Ce−Co alloys are large exothermic values. A comparison of the experimentally obtained results for the enthalpies of mixing of liquid alloys and those calculated by the regular Redlich‐Kister‐Muggianu model, taking into account only the data for binary constituent systems, indicates the specific exothermic ‘ternary’ contribution to the energy of formation of Al−Ce−Co ternary alloys. Data on the partial enthalpy of mixing of cobalt at infinite dilution indicate the involvement of cerium 4 f‐electron in the process of alloy formation.

show abstract

Reinvestigation of the Ce–Co–Al ternary system: Isothermal section at 973K

Cited by 5 publications

References 26 publications

Intermediate-valent CeCoAl – a commensurate modulated structure with short Ce–Co distances

Intermediate-valent CeCoAl – a commensurate modulated structure with short Ce–Co distances

Archives of Metallurgy and Materials

Enthalpies of Mixing in Al−Ce−Co Liquid Alloys

Contact Info

Product

Resources

About