Infrared spectrum and compressibility of Ti3GeC2 to 51 GPa

Using a synchrotron radiation source and a diamond anvil cell, we measured the pressure dependence of the lattice parameters of a polycrystalline Ti3GeC2 sample up to a pressure of 51 GPa. No phase transformations were observed. Like Ti3SiC2, and most other compounds belonging to the same family of ternary carbides and nitrides, the so-called MAX phases, the compressibility of Ti3GeC2 along the c axis is greater than that along the a axis. The bulk modulus is 197 ± 4 GPa, with a pressure derivative of 3.4 ± 0.1. We also characterized Ti3GeC2 by infrared spectroscopy; four of the five expected infrared modes were observed for this material.