First-principle calculations of thermodynamic properties of ZrC and ZrN at high pressures and high temperatures

First‐principles study of the thermal properties of Zr2C and Zr2CO

“…For the present study, calculation of the heat capacity of ZrC is used to validate the methods used to predict heat capacities for Zr 2 C and ZrCO. The black line in Figure 5A is the heat capacity of ZrC calculated by the current method, which fits well with the previous results calculated using quasi‐harmonic Debye, Debye–Slater, and Debye–Grüneisen models 35,36 . Heat capacities of Zr 2 C and Zr 2 CO at constant pressure are also shown in Figure 5B.…”

“…Thermal expansion coefficients of ZrC, Zr 2 C, and Zr 2 CO as function of temperature are shown in Figure 6. The volume thermal expansion coefficient of ZrC calculated using the methods in the current study is compared with values from simulations using the quasi‐harmonic approximation, 36 as well as with experimental values 37 as shown in Figure 6A. Values from the theoretical studies are higher than the experimental values because the simulations do not consider defects, flaws, or impurities.…”

Polymer‐Derived Ultra‐High Temperature Ceramics (UHTCs) and Related Materials

“…No experimental measurements of fusion enthalpies for Ti, Zr, Hf, and Ta carbides, borides and nitrides have been reported. First principles computations are increasingly used to evaluate thermodynamic properties of these compounds: thermal expansion and heat capacities were computed for ZrC and ZrN up to 3000-K [76] and the effect of carbon vacancies on miscibility gap in TiC-ZrC carbides was analyzed, [62] and melting temperatures were studied in the Hf-C-N system. [77] Since carbides, borides, and nitrides of transition metals are good electrical conductors, most of the measurements of their melting temperatures were performed by direct bulk heating of the samples with electric current using an experimental arrangement known as Pirany furnace.…”

The thermal shock behavior of Zr3[Al(Si)]4C6 and in situ (ZrB2+ZrC)/Zr3[Al(Si)]4C6 composite

“…As a result, Zr 3 [Al(Si)] 4 C 6 matrix composites reinforced by ZrB 2 and ZrC have been developed in our previous work, in which Zr 3 [Al(Si)] 4 C 6 matrix was toughened and strengthened significantly by the in situ incorporation of ZrB 2 and ZrC [13]. Moreover, in consideration of higher thermal conductivity of ZrB 2 and ZrC compared with monolithic Zr 3 [Al(Si)] 4 C 6 [5,14,15], improved thermal shock resistance of (ZrB 2 + ZrC)/Zr 3 [Al(Si)] 4 C 6 composite should also can be expected. So far, however, there are no relevant reports about the thermal shock behavior of monolithic Zr 3 [Al(Si)] 4 C 6 ceramic and Zr 3 [Al(Si)] 4 C 6 matrix composites.…”