Engineering topics
Publications and source records attributed to Miyagawa, I..
Hole-drilling technique uses special crystal driller in which drill bit rotates at fixed position at speed of 30 rpm while crystal slowly advances toward drill. Technique has been successfully applied to crystal of Rochell salt, Triglycine sulfate, and N-acetyglycine. Technique limits heat buildup and reduces strain on crystal.
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Growth of organic compounds from solution, in particular Rochelle salt and triglycine sulphate, was investigated. Ground-based experiments showed that gravity-driven convection currents in the growth solution influenced defect production in crystals, degraded ferroelectric quality, and indicated that an experiment done in a zero-gravity environment would be beneficial. A crystal of Rochelle salt was grown on board Skylab-4. The quality of this crystal was compared to earth-grown crystals and its unusual features were studied. A typical defect produced in this convection-free environment was a long straight tube extending in the direction of the c crystal axis. These tubes were much longer and more regularly arranged than in similar earth-grown crystals. The crystal was actually several crystals with corresponding axes parallel to each other. Ferroelectric hysteresis experiments showed that some parts of the crystal had many defects, while other parts were of extremely good quality.
The quality was investigated of a crystal of Rochelle salt grown from a solution placed in the zero-gravity environment of Skylab 4. The crystal has the following unique features: (1) the typical cavity is a long tube extending along the c-axis, the average length being 4mm, compared to 0.1mm that is the average size for earth-grown crystals; and (2) the crystal consists of several single crystals, the axes of which are parallel to each other. A preliminary measurement was made on the ferroelectric hysteresis curve of this Rochelle salt crystal.