Cold Sintering Process: New sintering technique for fabrication of nano-structured ceramics below 300 °C - A review

Due to the conventional understanding of sintering phenomenon in ceramic materials, considering two words of “cold” and “sintering” together may arise a doubt to a ceramic engineer since the usual sintering process has been accompanied by a heating regime at elevated temperatures. Recently, a new technique called Cold Sintering Process (CSP) has been introduced and developed as an ultra-low temperature sintering technique for nano-structured ceramics. With the aim of this process, a variety of ceramic materials can be sintered under uniaxial pressure of 100-500 MPa and at temperatures up to 300 °C. The development of CPS helps to reduce the sintering time and temperature significantly. In addition, this is a promising method for reducing the economic costs, the amount of energy consumption and the environmental damages caused by the use of conventional sintering processes. Besides, some especial microstructures and properties can be expected from ceramics fabricated by CSP method due to such low-sintering temperatures. This review article aims to summarize the latest finding on the cold sintering process for the fabrication of nano-structured ceramics. The history of CPS, introduction of equipment and process components, proposed mechanisms for densification as well as opportunities and challenges are analyzed and discussed. Some ceramic materials which were produced using this method are briefly described with process parameters.