Shape Control of MAX Phases by Biopolymer Sol-Gel Synthesis: Cr₂GaC Thick Films, Microspheres, and Hollow Microspheres

The class of MAX phases represents intriguing materials, as they combine ceramic and metallic properties quite exotically. Although many potential areas of application have been identified, a commercialization is still to be realized. This is particularly odd considering their existence of more than 60 years, however, less so considering the common synthesis techniques used. In fact, MAX phases are typically studied in either bulk or thin films, considerably hindering their integration into highly functional applications. Here, a facile and versatile sol-gel-based approach for the biopolymer-templated synthesis of MAX phase Cr₂GaC is introduced, capable of preparing the layered ternary carbide in a variety of technological useful shapes. We demonstrate for the first time how our wet chemical synthesis strategy immensely increases the accessibility of specific shapes and morphologies via the targeted synthesis of thick films, microspheres, and hollow microspheres.