Energy efficient sintering of high-performance ceramics

Developing high efficiency sintering technologies with mild conditions is crucial for reducing energy consumption and manipulating performances of ceramics. However, sintering ceramics at low temperatures in short times without pressure is challenging, due to their high melting points. Inspired by microwave resonance and dissolution-precipitation phenomena, an energy efficient sintering, microwave cold sintering process (MW-CSP), is proposed here to densify high-performance ceramics with significantly reduced sintering times and temperatures under pressureless conditions during the sintering stage. A range of ceramics including chlorides, oxides, phosphates and molybdates with various applications are shown to be well sintered by MW-CSP. TEM and phase-field simulation results demonstrate that the combination of transient liquid phase and microwave resonance improves the driving force of sintering. The mechanical and dielectric properties of selected materials are improved by 50 ~ 95%, while the energy consumption of MW-CSP is dramatically reduced by over 97% compared to other pressureless sintering technologies. These findings highlight the great potential of MW-CSP in efficiently densifying high-performance ceramics, opening up possibilities for energy saving sintering.