# A Study of the Thermodynamic Properties of Nd-C and Ce-C TRISO Fission Product Binary Systems
## 2 Materials and Methods
### Sample Cutting  
An MBRAUN Labstar Pro glovebox (sourced from MBRAUN, Garching, Germany) was used to store all carbide samples, and perform sample cutting as it provides an inert atmosphere of ultra-high purity argon gas, i.e., 99.999% Ar. The glovebox is equipped with H\({}_{2}\)O and O\({}_{2}\) sensors that were used to regulate atmospheric conditions, ensuring water vapor and oxygen levels remained at approximately 1-5 ppm. These sensors were monitored during the initial opening of the carbide samples from UTSA to assess if oxygen ingress occurred in the packaging. No noticeable increase in water or oxygen levels was observed. A small and a large antechamber are equipped on the side of the glovebox to permit ingress and egress of materials, and two lockable gloveports on the front of the glovebox allowed manipulation of tooling and equipment without exposure. The exhaust of both antechambers was fitted to a vacuum pump, with adjustable valving to inject either air or argon gas into the chamber. Use of the antechamber required its volume to be evacuated using the vacuum pump for 30 s, then re-filled with the necessary atmosphere, cycling three times before opening. The gloveports housed two black rubber gloves that were connected via pressed o-rings to maintain a pressure boundary, and the gloves were dressed with disposable extra-large nitrile gloves to prevent cross-contamination during sample work within the glovebox. An overview of the glovebox setup is provided in Figure 5. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Item** & **Mol\%C** & **Mol\%Ce** & **Compound** & \(\Delta\)**H\({}_{f}\) (25 \({}^{\circ}\)C) [k/mol]** & **Method** & **Ref.** \\ \hline
1 & 60 & 40 & Ce\({}_{2}\)C\({}_{3}\) & \(-88.3\pm 2.9\) & Calorimetry; & [40] \\ \hline
2 & 67 & 33 & CeC\({}_{2}\) & \(-104.7\) & Knudsen Cell Effusion; & [25] \\
3 & 67 & 33 & CeC\({}_{2}\) & \(-62.7\pm 21\) & Knudsen Cell MS; & [41] \\
4 & 67 & 33 & CeC\({}_{2}\) & \(-81.6\) & Knudsen Cell Effusion; & [33] \\
5 & 67 & 33 & CeC\({}_{2}\) & \(-97.1\pm 5.4\) & Calorimetry; & [40] \\
6 & 67 & 33 & CeC\({}_{2}\) & \(-76.2\pm 4.2\) & Calorimetry; & [34] \\
7 & 67 & 33 & CeC\({}_{2}\) & \(-120.1\pm 11\) & Quadruple Mass Spectrometer; & [30] \\
8 & 67 & 33 & CeC\({}_{2}\) & \(-88.5\pm 10.5\) & Electromotive Force; & [42] \\ \hline \end{tabular}
\end{table} 
Table 4: Cerium carbide enthalpy of formation values in the open literature. The small size and high hardness of the carbide samples introduced difficulty with resizing. Additionally, as rare earth carbides readily oxidize, any mechanical work required an inert environment, and therefore, had to be performed within the argon-filled glovebox. To perform the sample cutting, the following materials were required:  
1. Extra-large nitrile disposable gloves;
2. Anti-static weighing boats;
3. Kimtech wipes;
4. One pair of tweezers approximately 15 inches long;
5. One adjustable wrench;
6. Ziploc sandwich bags pre-labeled with the sample identity and unique numbering;
7. Ziploc large freezer bags to house the components for sample cutting and store the Ziploc sandwich bags containing the cut samples;
8. A large chisel approximately 12 inches long and 0.25 inches wide at its cutting face;
9. A rubber mallet approximately 3 inches in diameter at the contact face;
10. Three flat stainless steel electrical outlet cover plates to prevent damage to the glovebox were used;
11. Peelable sticky pads for holding the sample during cutting and cleaning the glovebox;
12. One DSC crucible for fit testing cut samples. Within the glovebox, the three stainless steel plates were stacked together with the curved side facing upwards, and peelable sticky pads were placed on top with the sticky side facing upwards. Next, Kimtech wipes were placed on the bottom surface inside of an unlabeled Ziploc freezer bag to assist in identifying cut samples. The plates and sticky pads were then inserted into the Ziploc freezer bag on top of the Kimtech wipes.