Director, Materials Research Laboratory, The Pennsylvania State Univ., University Park, Pa.
Pages: 19 Published: Jan 1965
The usefulness of high pressures in materials synthesis and tailor-making is considered in two different pressure ranges: below and above 10 kilobars.
Below 10 kilobars, high-pressure technology has made possible the controlled synthesis of special phases containing volatile components such as water, carbon dioxide, and oxygen, etc. Examples range from synthetic zeolites and micas to special valence state ferrimagnetics prepared under high oxygen pressures. High water pressure is also an excellent solvent for crystal growth and the most effective catalyst for attaining equilibrium in the subsolidus region of anhydrous nonmetallic systems.
Above 10 kilobars, a systematic crystal chemical approach to the synthesis of new materials has produced a large number of new high-pressure materials which can be retained under ambient conditions. These include a variety of simple oxides (e.g. B2O3, ZnO, SiO2, TiO2 PbO2) halides (BeF2, MnF2), semiconductors (silicon, germanium, etc.), ternary phases (a whole series of Ln3+PO4, Ln3+VO4, CaCO3, various garnets), noncrystalline dense glasses, etc.
Paper ID: STP45125S