| Abstract Scope |
Compression is an effective method to induce crystal transformation. Pressure as one key thermodynamic parameter can probe the driving force behind phase transition and equilibrium. In combination with regulating hosting metal, dopant concentration, and particle size, pressure can help access thermodynamic parameters of materials, which are the driving force for phase transition.
Two case studies using in situ high pressure XRD are shown. First is about a nuclear waste ceramic candidate orthosilicate zircon (ZrSiO4), crystallized into the I41/amd space group. Metals occupying the Zr site can be Ce, U, Th leading to isomorphic phases stetindite (CeSiO4), thorite (ThSiO4), coffinite (USiO4), and uranothorite (UxTh1-xSiO4). Changing of host and guest atoms both impact high-pressure phase transition to huttonite (P21/n) or to scheelite (I41/a). In the second case, a ternary I-III-VI2 semiconductor CuInSe2 was evaluated for the transition of metastable wurtzite-like nanocrystals, with implications for tailoring functional materials under extreme conditions. |