Light-Figure Phenomena Revealed and Crystal Faces Developed by Chemically Etched Nickel-Copper Alloy Crystals

The light-figure phenomena have been observed with single crystals of nickel-copper alloys containing 5～95 percent copper, etched with various chemical reagents, in order to obtain information regarding crystal faces developed by etching and to examine the suitability of the observed light figures to the orientation determination. The etching with boiling saturated aqueous solution of ferric chloride produces distinct light figures, suitable for the orientation determination, for all of alloy crystals, while any other reagent reveals only indistinct or no light figure. The main crystal faces developed by etching with ferric chloride solution are the {hk0}. {110} and {111}-vicinal faces, hk0 varying from 910 for nickel crystals over 610 for 20%Cu alloy crystals to 210 for 95%Cu alloy crystals

On the Solution-Body Phenomenon and Anisotropy of Solution Rate in Bismuth Crystals

The solution-body phenomenon has been investigated with bismuth single crystals, of circular-rod and sphere forms, etched with various reagents and some information concerning the anisotropy of solution rate has been obtained. It has been found that 31.6 percent nitric acid is only one reagent that produced clear-cut solution-bodies characteristic to the trigonal symmetry of bismuth crystal and that the rates of solution along various crystallographic directions in this reagent are in the order of V_>V_>V_V_>V_, V_ where h+k+l = 0 and m and n = any rational number. It is also shown that solution rates in 50 percent aqueous solution of 1 : 2 mixture of hydrochloric acid and nitric acid are in the same order as in 31.6 percent nitric acid, though the anisortopy is far smaller

On the Production of Single Crystals of Zinc, Bismuth and Tin by Sucking Up from Their Melts

The preparation of single crystals of zinc, bismuth and tin by sucking up from their melts was tried by the use of simple equipment and procedure and the effect of growing conditions upon the percentage of success and orientations of single crystals produced was studied. Single crystals, 5 mm in diameter and 5～7 cm in length, could be made with 20, 50 and 50 percent success for zinc, bismuth and tin, respectively, and they show a dominant preference of crystal orientations nearly perpendicular to the principal crystallographic axis, namely the hexagonal axis [0001] for zinc, trigonal axis [111] for bismuth, or tetragonal axis [001] for tin

The Light-Figure Phenomenon Revealed and Crystal Planes Developed by Etching in Tetragonal Tin Crystals and the Determination of Their Crystal Orientations by the Light-Figure Method. II : Orientation Determination by Light Figures

The application of light figures to the orientation determination of single crystal rods of tetragonal tin has been studied and the procedure for the perfect, accurate, and rapid determination has been worked out. Full accounts are given of the geometrical relationships and etching technique required for the orientation determination, of the directly and accurately measurable ranges and kinds of orientation angles, of the stereographic representation of crystal orientations, and of the accuracy and actual examples of the determination. The perfect determination of crystal orientations can be made with an accuracy within 0.1°by the use of {001}, {100} and {101} light figures revealed by etching with concentrated aqua regia. It is shown that the orientation determination by this method agrees well with that by the X-ray diffraction method

Light Figures and Surface Structures Revealed by Chemically Etched Germanium Single Crystals

Light figures projected on a plate screen from germanium single crystals, polished mechanically and etched with various chemical reagents, are examined in order to find out light figures or etching directions suitable for the orientation determination. In. formation regarding surface structures of germanium single crystals developed by mechanical polishing and by chemical etching has been obtained from the analysis of the observed light figures and from microscopic observations of crystal surfaces. It has been found that distinct light figures suitable for the orientation work are obtained by a short time etching with concentrated nitric acid plus water (1 : 1 and 3 : 7 ; 70℃), with concentrated nitric acid plus water plus hydrofluoric acid plus silver nitrate (45 cc+45 cc+10 cc+50 or 20 mg, and 20 cc+40 cc+40 cc+2 g), with hydrofluoric acid plus hydroperoxide plus water (1 : 1 : 4), and with 30 percent hydroperoxide (100℃). Among these etchants, hydrofluoric acid plus hydroperoxide plus water (1 : 1 : 4) is most suited for accurate orientation determination. Generally, crystal faces developed by etching have been found to be those belonging to the principal crystal zones, but dilute nitric acid heated at 70℃ develops some additional high-index crystal faces belonging to a high-index crystal zone. There is a tendency that low-index crystal faces appear by a short time etching and high-index ones by a prolonged etching. It is to be added that relatively clear light figures are obtained on germanium crystals as polished with silicon carbide powder

Effects of Growth Rates and Cooling Rates on Defect Generation in Melt-Grown Copper Crystals(Physics)

Single crystals of zone-refined Cu were grown from the melt at growth rates ranging from 0.1 to 29.0 mm/min and with cooling rates of the crystal after growth varying from 0.24 to 45℃/min. It was found that the growth rate had a very important effect on the generation of dislocations and their arrays, but the cooling rate of the crystal after growth had an important effect only when the crystal had been solidified at a rate of 0.1 mm/min

Light Figures of Zinc Crystals

Light figures were observed on the three principal crystallographic planes {0001}, {1120} and {1010} of zinc crystals, which were etched for various time-intervals with variously concentrated aqueous solutions of various acids, alkalis, and salts. The suitability of observed figures for determining orientations of zinc crystals with the light-figure method was examined, and light figures obtained by etching for 20 minutes with boiling saturated aqueous solution of potassium hydroxide was found to be the most suitable for the perfect determination (the determination of all angles which the geometrically predominated axis of a crystal makes with the hexagonal axis and digonal axes of the first or second kind)