Samples were also prepared without ball milling. Using a mortar and pestle, a total of 2 g of the same precursor powders in the same proportions were ground together for 45 min under Ar. They were then pressed and sealed as before. After ramping to 800 • C at 10 • C/min, they were held for 144 h before being quenched in an ice bath. Pellets were then ground before repeating the pressing and sealing process. The new tube was then placed in a preheated, 800 • C oven. Three 144 h cycles were completed.