Accession Number : AD0680675

Title :   GROWTH OF CRYSTALS BY CENTRIFUGATION.

Descriptive Note : Research Communication no. 71,

Corporate Author : DOUGLAS AIRCRAFT CO INC HUNTINGTON BEACH CALIF ADVANCED RESEARCH LABS

Personal Author(s) : Shlichta,Paul J. ; Knox,Robert E.

Report Date : SEP 1968

Pagination or Media Count : 28

Abstract : When a solution is rotated in a centrifuge, the solute ions, being denser than the solvent, tend to concentrate toward the outer edge of the cell. If the solution is initially near saturation, then the outer portions of the redistributed solution become supersaturated and crystal growth can occur. Under these conditions, many of the difficulties usually encountered in growing single crystals, such as dirt particles, air bubbles, or spurious seed crystals formed by evaporation at the solution surface, tend to be minimized or eliminated. On the other hand, there is some danger of crystal deformation due to the high force fields involved. Observations of crystal growth by centrifugation can also be used to measure several crystal growth parameters. Measurements of the threshold centrifugal field for crystallization of unseeded solutions can provide improved data on the supersaturation required for homogeneous nucleation. Determinations of the equilibrium form of the crystal at high g values can provide hitherto unobtainable measurements of crystal surface energy. Preliminary experiments have demonstrated the essential feasibility of these techniques, but numerous experimental difficulties must be overcome before usable crystals can be produced or accurate measurements made. (Author)

Descriptors :   (*CRYSTAL GROWTH, CENTRIFUGE SEPARATION), CENTRIFUGAL FIELDS, CENTRIFUGES, SINGLE CRYSTALS, NUCLEATION, SCHLIEREN PHOTOGRAPHY, LEAD COMPOUNDS, NITRATES

Subject Categories : Physical Chemistry
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE