Microwave-assisted ceramic calcination and sintering process: an alternative heat treatment to save energy

To obtain a more sustainable production of high-temperature superconductor ceramics according to the UN Sustainable Development Goals (SDGs), we propose the use of microwave-assisted heating. As example material, the Y ₃ Ba ₅ Cu ₈ O ₁₈ (Y358) compound with a superconducting transition temperature above 100 K was chosen, where the microwave heating was not previously applied. The calcination process of the Y358 compound was carefully studied by thermogravimetric analysis (TG/DTA) to define the range of the best-suited sintering temperatures. On this base, samples produced by employing conventional, resistance-heated furnaces are compared to the ones produced by microwave-assisted sintering. The microstructures of all samples were investigated in detail using XRD and SEM/EDS. Due to the shorter sintering time in the case of the microwave-assisted heating, the samples exhibit smaller grain sizes as compared to the conventional sintered samples. Combining the one-pot synthesis route developed previously with the microwave-assisted sintering, an effective and environmental-friendly processing route can be established.