Densification and grain growth in ceramics fabricated by cold sintering: A review on the effect of process parameters

The cold-sintering process (CSP) has been developed as an alternative method for the densification of ceramics at significantly low temperatures (<300°C) and in a short time (<2 h), with potential applications in the fabrication of high-performance ceramics and for the reliable integration of dissimilar materials such as metals, polymers, and ceramics into multifunctional devices. Relying upon the combined use of transient liquid media, mechanical pressure, and heat, CSP offers both fundamental and technological advantages compared with conventional sintering, minimizing energy consumption and enhancing the efficiency of the sintering process. Besides a brief overview of the densification mechanisms of CSP, knowledge obtained from earlier studies thus far regarding the effects on densification and grain growth behavior of various materials and processing parameters, such as the powder characteristics, solvent chemistry, temperature, heating rate, pressure, and dwell time, is discussed in detail in this review. Efforts that have been made to bring CSP technology into mainstream manufacturing are also described. Challenges and opportunities related to the preparation of the starting materials, the tooling quality, optimization of the process parameters, and in situ and ex situ characterization of sintered materials for the development of high-performance ceramics by the CSP method are also explored.