An Effective Strategy to Inhibit Grain Coarsening: Construction of Multi-Element Co-Segregated Grain Boundary Complexion

When exposed to moderate to high temperatures, nanomaterials typically suffer from severe grain coarsening, which has long been a major concern that prevents their wider applications. Here, we proposed an effective strategy to inhibit grain coarsening by constructing grain boundary (GB) complexions with multiple codoped dopants, which hindered coarsening from both energetic and kinetic perspectives. To demonstrate the feasibility of this strategy, multiple selected dopants were doped into a ZrO2-SiO2 nanocrystalline glass ceramic (NCGC) to form GB complexions. The results showed that NCGC was predominantly composed of ZrO2 nanocrystallites (NCs) distributed in an amorphous SiO2 matrix. Ultrathin layers of GB complexions (similar to 2.5 nm) were formed between adjacent ZrO2 NCs, and they were crystalline superstructures with co-segregated dopants. In addition, a small amount of quartz solid solution was formed, and it adhered to the periphery of ZrO2 NCs and bridged the adjacent NCs, acting as a "bridging phase". The GB complexions and the "bridging phase" synergistically enhanced the coarsening resistance of ZrO2 NCs up to 1000 degrees C. These findings are important for understanding GB complexions and are expected to provide new insights into the design of nanomaterials with excellent thermodynamic stability.