Hybrid laser-microwave sintering of zirconia-base ceramics

Abstract

The development of microstructures and properties in sintered ceramic materials is known to depend on the temperature-time processing path. A new hybrid process for ultra-rapid sintering zirconia-base (3Y2O3-ZrO2) ceramics has been reported combining irradiation by a pulsed Nd:YAG laser and a continuous, multi-mode, 2.45 GHz microwave energy source. With this hybrid laser-microwave process, it is possible to heat samples at ultra-high rates to 1700 C and beyond, and to produce dense, crack-free samples with an average grain size of 20 nm. In this paper, it is shown that the hybrid laser-microwave process heats to higher temperatures than is possible if the microwave heating is replaced by resistance heating. Further, our results suggest that microwave irradiation sustains plasma bursts observed when microwave heating is replaced by resistance heating. The unique time-temperature path attained in the hybrid process establishes the synergy of microwave and laser energy sources. Owing to this path, the hybrid process produces sintered microstructures that have not been attained employing microwave heating, laser heating or resistance furnace heating alone.The development of microstructures and properties in sintered ceramic materials is known to depend on the temperature-time processing path. A new hybrid process for ultra-rapid sintering zirconia-base (3Y2O3-ZrO2) ceramics has been reported combining irradiation by a pulsed Nd:YAG laser and a continuous, multi-mode, 2.45 GHz microwave energy source. With this hybrid laser-microwave process, it is possible to heat samples at ultra-high rates to 1700 C and beyond, and to produce dense, crack-free samples with an average grain size of 20 nm. In this paper, it is shown that the hybrid laser-microwave process heats to higher temperatures than is possible if the microwave heating is replaced by resistance heating. Further, our results suggest that microwave irradiation sustains plasma bursts observed when microwave heating is replaced by resistance heating. The unique time-temperature path attained in the hybrid process establishes the synergy of microwave and laser energy sources. Owing to this path, the hybri...