372595893

JPRS-UMS-92-003 16 March 1992

PREPARATIONS

35

Growing of Single Crystals of Cul and Its Certain Properties

927D0068K Moscow IZVESTIYA AKADEMII NAUK SSSR: SERIYA NEORGANICHESKIYE MATERIAŁY in Russiart Vol 27 No 12, Dec 91 pp 2624-2628

[Articlc by V.I. Popolitov, Crystallography Institute imeni A.V. Shubnikov at the USSR Academy of Sciences]

U DC 542.65

[Abstract] The changes in the structure and lattice con-stants of copper monoiodide single crystals with an increase in temperaturę whereby the cubic lattice of the y-phase is reordered into a wurtzite-type lattice of the p-phase, then again becomes cubic while the high-temperature Cul a-phase has a superionic conduction, are investigated and the solubility of copper iodide in aąueous Solutions of HI is examined in a 200-300°C temperaturę rangę at a constant 5.05 x 10⁷ Pa pressure. The dependence of the single crystals of copper iodide on the HI concentration at various temperatures, the dependence of the solubility logarithm of the copper iodide crystals on the inverse value of temperaturę at various concentrations of HI, the dependence of the (111) face growth ratę of Cul single crystals on the HI concentration at various temperaturę gradients, the exciton reflec-tion spectra of Cul single crystals under optimum and nonoptimum conditions, and Cul single crystal photolu-minescence spectra are plotted. An analysis reveals the following optimum growth conditions of the principal tetrahedral face of Cul single crystals: an HI concentration of 32-25% by mass, a temperaturę of 230-270°C, and a temperaturę drop of 25-30°. The dependence of the growth ratę of the fast growing tetrahedral (111) face on the HI concentration and temperaturę is exponential, and linear on the temperaturę drop. Figures 5; references 3.

Growing of MgGa₂S₄ Single Cry stals and Their Photoelectric Properties

927D00680 Moscow IZYESTIYA AKADEMII NAUK SSSR: SERIYA NEORGANICHESKIYE MATERIAŁY in Russian Vol 27 No 12, Dec 91 pp 2655-2656

[Article by N.A. Moldovin, Applied Physics Institute at the Moldova Academy of Sciences]

UDC 546.784731

[Abstract] The issue of developing detectors with a spectral response in the ultraviolet (UF) band for solid-state photoelectronics applications is addressed and an attempt to grow MgGa₂S₄ single crystals and examine their photoelectric properties is described. The single crystals were produced in a closed system by the method of iodide Chemical transport with preliminary fusion ofa charge of elementary components taken in a stoichio-metric ratio. The photoconduction and transmission spectra of MgGa₂S₄ and MgAlo^Ga, ₈S₄ crystals are investigated and plotted. The photoconduction mecha-nism which determines the position of the red photoelectric threshold is examined and the limit of aluminum atom concentration at which the MgAl_xGa₂._xS₄ single crystal stability is maintained under exposure to mois-ture and air is established. It is demonstrated that MgGa₂S₄ crystals are characterizcd by considerable pho-tosensitivity to ultraviolet radiation and their photoconduction is intrinsic in origin. This compound’s forbidden gap width is found to be equal to E_g = 3.4 eV at a 300K temperaturę. Figures 1; references 4: 3 Russian, 1 Western.

Production of Promising Types of Metal Products by Continuous Horizontal Two-Sided Casting Method

927D0061C Moscow STAŁ in Russian No 12, Dec 91 pp 16-17

[Article by V.M. Sinitskiy, A.I. Mayorov, L.P. Zakov, M.V. Panin, M.D. Zharnitskiy, All-Union Science Research Institute of Metallurgical Machine-Building]

UDC 621.746.27.047

[Abstract] The advantages of two-sided continuous horizontal casting are outlined and recent development in the field of making thin Steel slabs by this method are discussed; the principal factors afTecting the stability of the casting process and products are examined. The microstructure of a thin slab cast from transformer Steel and the microstructure of bimetal produced by this method are investigated. The process makes it possible to cast 40-50 mm Steel slabs and two-layercd clad metal billets with a 1:2.5 ratio of base metal to cladding in a continuous casting machinę (MNLZ); the method also makes it possible to expand the rangę of slab brands and dimensions, including those from electrical sheet and transformer Steel with a 3% Silicon content and corrosion resistant Steel. Studies demonstrate the good ductility of the resulting slabs. The use of the method is especially efTicient at small-scale metal works and other specialty Steel plants. Figures 2; references 3.

Correcting Titanium Content Within Narrow Rangę in Continuous Casting Machinę During Pipę Steel Making

927D0061D Moscow STAL in Russian No 12, Dec 91 pp 18-19

[Articlc by A.I. Trotsan, B.F. Belov, V.M. Dolgan, D.Yu. Levin, O.V. Nosochenko, G.A. Nikolayev, Mechanics Problems Institute at the Ukrainian Academy of Sciences, Central Scientific Research Institute of Ferrous Metallurgy, and Azovstal Integrated Iron and Steel Works]