Preparation of (ZrTiCoNiNb)Ox high entropy ceramics by microwave sintering

Microwave sintering, owing to its unique volumetric heating mode and field effects, can significantly reduce the synthesis temperature and energy consumption of high-entropy ceramics, greatly enhance sintering efficiency, and promote interdiffusion among constituent elements. It is crucial for obtaining high-performance high-entropy ceramics with superior structures. (ZrTiCoNiNb)O x high entropy ceramics were prepared using microwave sintering at temperatures from 800 °C to 1100 °C. The effects of sintering temperature and heating rate on the samples during microwave preparation were investigated. The results indicated that high-entropy ceramics of (ZrTiCoNiNb)O x were successfully prepared at 800 °C for 20 min by microwave sintering. The unique thermal effects of microwave heating effectively facilitated low-temperature synthesis of high-entropy ceramics. As the sintering temperature increased, the porosity of the ceramics gradually decreases, and the Vickers hardness reached 6.712 GPa. At the same time, adjusting the heating rate helped reduce cracking due to thermal stress. The mechanical properties of the sample could also be further improved. At 1100 °C and a heating rate of 15 °C/min, the hardness increased to 7.165 GPa. Higher sintering temperatures and heating rates help improve the response to microwaves and the diffusion ability of the components in the samples. This study provided a new method for rapid and effective preparation of high-entropy ceramics.