scholarly journals Equilibria between Alumina Crucible and Carbon Dissolved in Iron

1962 ◽  
Vol 26 (12) ◽  
pp. 769-773
Author(s):  
Kichizo Niwa ◽  
Masahiro Shinmei ◽  
Takeshi Kudo ◽  
Kou Miyamura
Keyword(s):  
Author(s):  
A. R. Landa Canovas ◽  
L.C. Otero Diaz ◽  
T. White ◽  
B.G. Hyde

X-Ray diffraction revealed two intermediate phases in the system MnS+Er2S3,:MnEr2S4= MnS.Er2S3, and MnEr4S7= MnS.2Er2S3. Their structures may be described as NaCl type, chemically twinned at the unit cell level, and isostructural with CaTi2O4, and Y5S7 respectively; i.e. {l13} NaCl twin band widths are (4,4) and (4,3).The present study was to search for structurally-related (twinned B.) structures and or possible disorder, using the more sensitive and appropiate technigue of electron microscopy/diffraction.A sample with nominal composition MnEr2S4 was made by heating Mn3O4 and Er2O3 in a graphite crucible and a 5% H2S in Ar gas flow at 1500°C for 4 hours. A small amount of this material was thenannealed, in an alumina crucible, contained in sealed evacuated silica tube, for 24 days at 1100°C. Both samples were studied by X-ray powder diffraction, and in JEOL 2000 FX and 4000 EX microscopes.


1988 ◽  
Vol 124 ◽  
Author(s):  
S. L. McGill ◽  
J. W. Walkiewicz ◽  
G. A. Smyres

ABSTRACTThe effect of power level on the microwave heating characteristics of a variety of reagent-grade chemicals and minerals has been determined in a Bureau of Mines study. Heating rates of the powdered samples are presented for incident power ranging from 500 to 2,000 W at 2.45 GHz. The apparatus consisted of a WR 975 waveguide-applicator mounted to WR 284 waveguide sections and connected to a 3-kW power source. Tests were conducted in an alumina crucible enclosed in a fused-quartz beaker that was fitted with a Teflon lid to allow for a controlled inert atmosphere and thermocouple insertion. In general, heating rates increased as input power increased. Exceptions to this were some very high-lossy (microwave receptive) and very low-lossy materials that showed negligible changes with increased power. Microwave data collected should provide insight as to possible chemical and mineral processing applications as well as to assist in predictions of processing parameters.


1968 ◽  
Vol 7 (12) ◽  
pp. 1539-1539
Author(s):  
Yasuaki Nakagawa ◽  
Shin-ichi Nakamura

2010 ◽  
Vol 1265 ◽  
Author(s):  
Sergey Stefanovsky ◽  
Alexander Ptashkin ◽  
Oleg Knyazev ◽  
Olga Stefanovsky ◽  
James C Marra

AbstractSavannah River Site Defense Waste Processing Facility (DWPF) Sludge Batch 4 (SB4) high level waste (HLW) simulant at 55 wt % waste loading was produced in the demountable cold crucible and cooled to room temperature in the cold crucible. Appreciable losses of Cs, S and Cl took place during the melting. A second glass sample was subjected to canister centerline cooling (CCC) regime in an alumina crucible in a resistive furnace. X-ray diffraction (XRD) study showed that the glass blocks were composed of vitreous and spinel structure phases. No separate U-bearing phases were found.


1986 ◽  
Vol 77 ◽  
Author(s):  
A. F. Jankowski ◽  
R. O. Adams ◽  
L. Williams

ABSTRACTThe binary alloy series of Ti-X metallic, composition modulated layered structures has been fabricated via magnetron sputtering. The Ti-X systems (where X is Ta, Mo, or V) explored are exemplary of solid solution systems, such as the supermodulus systems of Cu-Ni, Ag-Pd, Au-Ni, and Cu-Pd (which all feature fee crystalline compatibility). In the present case, the beta-phase of Ti sought in these Ti-X systems suggests bec crystalline compatibility, with interlayer misfit strains not exceeding 10%.The Ti-X series examined, matches elements of high and low atomic number. (Z of Ti, V, Mo, and Ta are 22, 23, 42, and 73, respectively.) Difficulties which arise in a conventional tungsten basket - alumina crucible physical vapor deposition process, i.e. obtaining thr vaporization temperatures for Ti, V, Mo and Ta of 1235, 1332, 1822, and 2240 °C at 130 mPa, respectively, are overcome by magnetron sputtering. Thin films produced by alternate deposition of Ti with V, Mo, or Ta, are desired with individually unique, regular repeating layer thicknesses which range from 1.5 to 15 nm.An initial characterization of the Ti-X composition modulated alloys has been conducted using X-ray diffraction. The pole figure constructions of the various composition wavelengths give a qualitative look at the strain accomodation within the thin films and possible manifestations in mechanical properties.


1986 ◽  
Vol 27 (5) ◽  
pp. 372-381 ◽  
Author(s):  
Takehiro Dan ◽  
Noriyoshi Aritomi ◽  
Kazuyuki Ogawa ◽  
Yoshisuke Nakamura

Author(s):  
D. L. Ellis ◽  
G. M. Michal

A material with high thermal conductivity and mechanical strength at elevated temperatures is required for certain aerospace applications. Copper based alloys precipitation hardened with near zero solubility phases are candidate materials. Utilizing rapid solidification technology, elements such as Cr and Nb can be dissolved into liquid copper and fully precipitated out in the solid state. However, such elemental precipitates readily coarsen at elevated temperatures. The aim of this work was to create a more stable refractory metal intermetallic phase, C2Nb, in an essentially pure copper matrix via melt spinning.Ribbon was produced by induction melting a master alloy in an alumina crucible with a hole diameter of 1 mm (0.040-inch) using a graphite susceptor under an argon atmosphere. The alloy was heated to 1593°C (2900°F)and ejected onto a Cu wheel with a surface velocity of 20 m/s using a pressure of 0.07 MPa (10 psi). The resulting composition of the ribbon was 1.95 a/o Cr and 0.48 a/o Nb as determined by bulk spectrographic analysis.


1996 ◽  
Vol 60 (398) ◽  
pp. 115-130 ◽  
Author(s):  
Jon K. Seedhouse ◽  
Colin H. Donaldson

AbstractCompositional convection in magma chambers is thought to be an important process in the fractionation of liquid from crystals during the differentiation of magmas. It has been tested for in this study by undertaking isothermal crystal growth experiments in a silicate melt at atmospheric pressure in air. The melt used is a synthetic basalt in which iron is replaced by cobalt to minimise redox problems. Co-Mg olivine rims were overgrown on forsteritic olivine seeds cemented to the floor of a 2.4 cm deep alumina crucible. Following quenching and sectioning, glasses were examined optically for colour variations and by EPMA for compositional variations. It had been expected that the colour intensity of the blue glass would diminish in the Co-depleted zone that develops around crystal overgrowths, whereas in fact little difference is normally found, except for a slight fading of colour in glass above the apex of a seed in a few experiments. By contrast EPMA revealed zones up to 50 μm wide around seeds that are depleted in Co and Mg by up to 25 % at the crystal-glass interface and in patches above some crystals. Contour maps of X-ray count-rate data obtained in grids of analytical points show Co- and Mg-depleted glass around the overgrowths and in patches above the highest point of each seed, demonstrating that convection in the melt does occur during growth of individual crystals. As the experiments were carried out in a stable temperature gradient and the crystal seeds had no contact with the melt meniscus, thermal and surface-tensional convection are both eliminated, and the convection is inferred to be caused by a density difference resulting from compositional variation across the chemical boundary layer around a growing crystal. The density difference between the inside and outside of a boundary layer is calculated to be approximately −1%.


Sign in / Sign up

Export Citation Format

Share Document