Challenges for cold sintering techn

Challenges for cold sintering technology exist scientifically and industrially. The most pressing scientific challenges are associated with our beginner’s knowledge of densification in the presence of pressure, temperature, and ions in solution, and our appreciation for the dynamic nature of this process. The importance of many factors need to be addressed: examples of which we are aware include grain size, grain morphology, particle size distribution, die sealing, rate of pressure application, and liquid phase viscosity. For select materials we understand several of these factors, but a generalized framework that can be applied to many compositions needs developing. While there are many formulations amenable to cold sintering, there is an equal number that challenge the process. In particular, extremely low solubility binary oxides like Ta2O5, ternary compounds with very disparate cation solubilities like LaNbO3, and compounds with very stable hydroxides or carbonates like MgO and CaO respectively, provide significant processing challenges. These challenges, however, are not fundamental, rather they are limitations presented by incomplete understanding and unexplored processing space. For example, hydroxide and carbonate phases can be mediated by an alternative liquid phase. We have only scratched the surface of cold sintering experimental space and anticipate rapid advances as additional researchers engage the opportunity.