Thermodynamic Properties of the Tantalum and Tungsten Borides

Leitnaker, J.M.; Bowman, M.G.; Gilles, Paul W.

doi:10.1149/1.2425442

Cited by 15 publications

(6 citation statements)

References 4 publications

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“…Moreover, the activation energy was determined for the temperature range of 1400-1900 • C, which is consistent with the microstructure evolution under discussion (2000 • C). Leitnaker et al 72 suggested that the heat of formation of TaB was 160 kJ/mol, whereas other borides, including TaB 2 , should have the heat of formations between 160 and 270 kJ/mol. The results of the numerical simulation of the growth process for Ta 3 B 4 are presented in Figure 9 (see Section S5 and video files for details).…”

Section: 33mentioning

confidence: 99%

High‐temperature reactive synthesis of the Zr–Ta multiboride with a supercomposite structure

et al. 2022

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This study reports the formation of a ceramic composite consisting only of boride phases with an artificially created hierarchical superstructure. Such a composite was formed during the reaction‐driven consolidation process using a mixture of ZrB2, tantalum, and amorphous boron powders. The homogeneity of the reaction among these powders at 1900°C allowed the forming of a highly reproducible and repetitive superstructure where Ta3B4 forms a chain‐like mesh that entraps the ZrB2, ZrB, TaB, and (Zr,Ta)B2 phases. The multiboride ceramic composite exhibited extremely high hardness: 28.6 ± 3.2 or 22.6 ± 0.6 GPa. These were estimated using 98‐ and 196‐N loads, respectively. At 2000°C, the multiboride composite showed a strength of nearly 400 MPa and fractured in an elastic manner at the loading rate of 2.5 mm/min. This level of strength is usually observed for the bulk zirconium diboride at room temperature. The main factors leading to the improvement of the mechanical properties were considered to be the formation of the (Zr,Ta)B2 solid solution as well the composite structure.

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Section: 33mentioning

confidence: 99%

High‐temperature reactive synthesis of the Zr–Ta multiboride with a supercomposite structure

et al. 2022

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“…In treatments (3), (4), and (5) , the heat of formation is calculated assuming the boride phas e to be nonstoichiometric, however, an equivalent result is obtained if we assume the aluminum boride to be stoichiometric but accompanied by an e xcess of elemental boron. With the application of a correction for this excess , th e c alculation of the heats of formation of the stoichiometric and nonstoichiometric formulas become identical.…”

Section: Analysis Of Combustion Residuesmentioning

confidence: 99%

Heats of formation of aluminum diboride and a-aluminum dodecaboride

Domalski¹,

Armstrong²

1967

J. RES. NATL. BUR. STAN. SECT. A.

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The en e rgies of co mbu s ti on of AlB" and a-A lB" were me asured in a bomb . ca lor im e ter us in g Auorin e as th e ox idant. Major probl e ms of thi s inves tigation were the assessment of th e stat e and di s· tribution of impuriti es in the sa mpl es and the establi s hm e nt of the s toi c hiom etry of th e a luminum boride ph ase. W e obtain -16 ± .3 kcal mol -' and -48 ± 10 kcal mor' for th e heat s of formation of A I B, a nd a·AIB,", res pec tively. Th e unce rtainti es c it ed are th e overa ll ex pe rim e ntal errors. Their magnitud es a re c hi e Ay du e to uncertainti es in th e impurity co rrec tion appli ed and th e un ce rtainties in the heats of formation of th e co mbustion produc ts.

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“…As there is no relevant data on the phase of TaB in FactSage database, the Gibbs free energy change curve of TaB generated by Ta and B reaction cannot be calculated by FactSage. Therefore, CrB is used to judge the difficulty of the reaction between Ta and B, which has the same crystal structure with TaB 31–33 . Therefore, in the initial stage of high‐energy ball milling, solute tantalum tends to dissolve carbon atoms first, followed by nitrogen atoms, and then boron atoms 34 .…”

Section: Resultsmentioning

confidence: 99%

Ta(B, C, N) and (Ta, Mi)(B, C, N) (Mi = Nb, W) ceramics by high‐energy ball milling: processing and solution mechanisms

Guan

Yang

et al. 2022

J Am Ceram Soc.

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In order to study the solid‐solution process between amorphous BCN and metal Ta, Ta(B, C, N), (Ta, Nb)(B, C, N), and (Ta, W)(B, C, N) ceramics were prepared by high‐energy ball milling, and their phase composition, microstructures, and binding bonds have been analyzed. The results show that all the three ceramics are hard agglomeration state, formed by stacking of nanoparticles. The mechanical alloying process is accompanied by the formation of chemical bonds, such as B–Ta, N–Ta, C–Ta, and O–Ta for Ta(B, C, N) ceramic, and the order of solid solution is C > N > B. When heated at 1500°C, a second diboride phase precipitates from (Ta, Nb)(B, C, N) ceramic, whereas the second phase of WC gradually dissolved from (Ta, W)(B, C, N) ceramic. This work provides theoretical and data supporting to analyze the solid‐solution process of Ta(B, C, N) ceramic.

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Thermodynamic Properties of the Tantalum and Tungsten Borides

Abstract: not Available.

Cited by 15 publications

References 4 publications

High‐temperature reactive synthesis of the Zr–Ta multiboride with a supercomposite structure

High‐temperature reactive synthesis of the Zr–Ta multiboride with a supercomposite structure

Heats of formation of aluminum diboride and a-aluminum dodecaboride

Ta(B, C, N) and (Ta, Mi)(B, C, N) (Mi = Nb, W) ceramics by high‐energy ball milling: processing and solution mechanisms

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