Ultrafast high-temperature sintering to avoid metal loss toward high-performance and scalable cermets

Summary

Cermets embrace the high hardness of a ceramic and the good ductility of a metal. Therefore, they potentially meet the ever-increasing demands of new materials for harsh environments in energy generation and conversion. However, cermet sintering faces many challenges, such as metal volatilization, grain coarsening, and poor wettability of the metal with the ceramic, which affect the microstructure and thus mechanical properties. Herein, we apply an ultrafast high-temperature sintering (UHS) method to sinter cermets at a high temperature in only seconds. The high temperature leads to good wettability of the metal with the ceramic, while the short sintering time limits the loss of metal components and accurately controls the grain growth. We demonstrate the UHS method using a model cermet composed of a Ni-based superalloy and aluminum oxide, where we obtain dense microstructure, minimal nickel loss, and uniform grain size. Owing to these merits, good mechanical properties and oxidation resistance are achieved.