Synthesis, mechanical and physical properties of bulk Zr2Al4C5 ceramic

Bulk Zr2Al4C5 ceramics was synthesized by an in situ reactive hot-pressing process using ZrC, Al and carbon black as staring materials. The reaction path of synthesis was discussed based on differential thermal analysis, Raman spectra and X-ray diffraction results. Compared with the reported Zr2Al3C4, Zr2Al4C5 has a relatively high hardness (Vickers hardness of 12.2 GPa), superior strength (flexural strength of 420 MPa) and lower electrical resistivity (1.05 μΩ m). In addition, the room-temperature thermal conductivity value, 14.6 W (m K)−1 for Zr2Al4C5, was smaller than the value for Zr2A3C4 ceramics (15.5 W (m K)−1), and the heat capacity of Zr2Al4C5 is much higher than that of Zr2A3C4 in the overall temperature range. The results here indicated that Zr2Al4C5 is a potential high-temperature structural ceramic.