Spark Plasma Sintering: A Brief Survey of Recent Patents

The Spark Plasma Sintering (SPS) process has dramatically changed the way scientists and engineers sinter materials. Using the SPS near theoretical packing densities can be attained for a wide variety of materials at a lower sintering temperature in a shorter period of time than other sintering processes due to the highly localized Joule heating, electric current/field enhanced mass transport, spark plasma/discharge, and applied pressure. Importantly, the SPS process allows for a greater control of micro-morphology. To date, the SPS process has been widely employed for various applications such as the processing and synthesis of functional materials. In particular, the field of thermoelectricity has found a large interest in the SPS process, where considerably higher thermoelectric performance has been achieved due to the use of SPS in materials processing. In addition, metallurgists and material scientists have found that the SPS process helps fabricate more robust rare earth magnets and fuel cell constituents. This short review will mainly focus on the recent patents of SPS process, especially those in the category of nanomaterials/composites for mechanical use, thermoelectric materials, electromagnetic functional materials, and fuel cell components.