| From research efforts in medicine to cutting edge technology, nature has often been the greatest resource for innovative experimentation and clairvoyance. Likewise, nature has set the precedence for the origin of hydrothermal synthesis. Originating from mineralogical studies, the initial attempts at hydrothermal synthesis endeavored to duplicate the natural process of mineral paragenesis. In recent years, synthesis via hydrothermal techniques has found some application in growing single crystals of inorganic origin. Creating avenues of synthesis for metal oxides to complex silicates, hydrothermal synthesis is employed not only for the growth of crystals but also in the study of the behavior of substances under hydrothermal conditions. In 1943, hydrothermal synthesis transitioned from exploratory mineralogical work to a legitimate synthetic technique as Bell Laboratories began continental industrial growth of alpha-quartz.; Although there is some ambiguity, hydrothermal synthesis generally refers to heterogeneous reactions in aqueous media above 100°C and 14.9 PSI. However, it is important to note that advancements in the reaction vessels have afforded temperatures and pressures well in excess of this generic definition. The evolution of reaction vessels from simple shotgun shells to sophisticated high-temperature, high-pressure metal alloy based reaction vessels, allow the researcher to comfortably work in conditions >500°C and >40kPSI. This range of flexibility allows further exploitation of the positive aspects of hydrothermal synthesis (i.e. PVTC relations) and dares to supersede incumbent high temperature growth techniques such as flux laser heated pedestal growth, floating zone method, top seeded solution growths and Czochralski (CZ) pulls.; The following thesis will emphasize the fundamental studies utilized to investigate the hydrothermal growth of select crystal systems. The inaugural study is an exploratory investigation into the hydrothermal synthesis of sodium iron phosphates. Within this work, the effect of variant pH and temperature will be analyzed in efforts to influence and tailor the hydrothermal growth of a crystal. Motivation for this research lies within the search for open framework structures equipped with large voids or channels and redox active transition metals for application in rechargeable batteries. The latter projects (KTP, YVO4 and TiO2) will focus on the hydrothermal synthetic technique in preparation from industrial growth. |
