# A Study of the Thermodynamic Properties of Nd-C and Ce-C TRISO Fission Product Binary Systems
## 3 Results
### Experimental Results
#### 3.4.1 Neodymium-Carbon  
A temperature-composition isobaric phase diagram of the Nd-C system is shown in Figure 18, providing a comparison of the results from the DSC measurements completed in this work with existing data in the open literature, and Figure 19 shows the low-temperature eutectic region. The basis for the predicted phase changes is derived from the work by [PERSON] et al., with experimental data referenced accordingly. Note that the predicted phase \begin{table}
\begin{tabular}{c c c c c} \hline
**Compound** & **Phase Transition** & \(\Delta\)H\({}_{f}\) (25 \({}^{\circ}\)C) [kJ/mol] & \(\Delta\)H\({}_{fxn}\)[kJ/mol] & **References** \\ \hline Ce\({}_{0.8}\)C\({}_{0.2}\) & Eutectic & - & \(-0.11\) & This work \\ Ce\({}_{0.68}\)C\({}_{0.32}\) & \(\gamma\)Ce + Ce\({}_{2}\)C\({}_{3}\) = Ce\({}_{2}\)C\({}_{3}\) + L & - & \(-0.01\) & This work \\ Liquidus & - & \(-0.01\) & This work \\ Ce\({}_{0.33}\)C\({}_{0.67}\) & \(\alpha\)CeC\({}_{2}\) \(\leftrightarrow\beta\)CeC\({}_{2}\) & - & \(-2.62\) & This work \\ Ce\({}_{0.33}\)C\({}_{0.67}\) & - & \(-104.7\) & - & [25] \\  & & \(-62.7\pm 21\) & - & [41] \\  & & \(-81.6\) & - & [33] \\  & & \(-97.1\pm 5.4\) & - & [40] \\  & & \(-76.2\pm 4.2\) & - & [34] \\  & & \(-120.1\pm 11\) & - & [30] \\  & & \(-88.5\pm 10.5\) & - & [42] \\ Ce\({}_{0.4}\)C\({}_{0.6}\) & - & \(-88.3\pm 2.9\) & - & [40] \\ \hline \end{tabular}
\end{table} 
Table 10: Measured enthalpies of fusion of Ce-C from this work and enthalpies of formation from the open literature. \begin{table}
\begin{tabular}{c c c c} \hline
**Compound** & **Phase Transition** & \(\Delta\)H\({}_{f}\) (25 \({}^{\circ}\)C) [kJ/mol] & \(\Delta\)H\({}_{fxn}\)[kJ/mol] & **References** \\ \hline Nd\({}_{0.9}\)C\({}_{0.1}\) & HCP + Nd\({}_{2}\)C\({}_{3}\) \(\rightleftharpoons\) HCP + L & - & \(-1.1\) & This work \\ HCP + L \(\equiv\) BCC + L & - & \(-0.96\) & This work \\ Liquidus & - & \(-3.52\) & This work \\ Nd\({}_{0.84}\)C\({}_{0.16}\) & HCP + Nd\({}_{2}\)C\({}_{3}\) \(\rightleftharpoons\) HCP + L & - & \(-0.41\) & This work \\ Liquidus & - & \(-0.35\) & This work \\ Nd\({}_{0.8}\)C\({}_{0.2}\) & Eutectic & - & \(-0.35\) & This work \\ Nd\({}_{0.75}\)C\({}_{0.25}\) & HCP + Nd\({}_{2}\)C\({}_{3}\) \(\rightleftharpoons\) Nd\({}_{2}\)C\({}_{3}\) + L & - & \(-0.01\) & This work \\ Nd\({}_{0.7}\)C\({}_{0.3}\) & HCP + Nd\({}_{2}\)C\({}_{3}\) \(\rightleftharpoons\) Nd\({}_{2}\)C\({}_{3}\) + L & - & \(-3.26\) & This work \\ Liquidus & - & \(-6.87\) & This work \\ Nd\({}_{0.65}\)C\({}_{0.35}\) & HCP + Nd\({}_{2}\)C\({}_{3}\) \(\rightleftharpoons\) Nd\({}_{2}\)C\({}_{3}\) + L & - & \(-1.82\) & This work \\ Nd\({}_{0.6}\)C\({}_{0.4}\) & HCP + Nd\({}_{2}\)C\({}_{3}\) \(\rightleftharpoons\) Nd\({}_{2}\)C\({}_{3}\) + L & - & - & This work \\ Liquidus & - & \(-10.8\) & This work \\ Nd\({}_{0.4}\)C\({}_{0.6}\) & - & \(-34.1\pm 3\) & - & [22] \\ Nd\({}_{0.33}\)C\({}_{0.67}\) & - & \(-29.2\pm 1.4\) & - & [22] \\ Nd\({}_{0.33}\)C\({}_{0.67}\) & - & \(-90.8\pm 6\) & - & [29] \\  & - & \(-17.4\pm 3\) & - & [25] \\  & - & \(-29.33\pm 3\) & - & [22] \\ \hline \end{tabular}
\end{table} 
Table 8: Measured enthalpies of fusion of Nd-C from this work and enthalpies of formation from the open literature.