ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15359.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Samples of basic and alumina brick were examined after service in copper anode furnaces. Copper oxides penetrating the brick had reacted with the chrome grains, with the periclase, and with the alumina. These reactions were studied by examining the stability of the compounds formed when copper oxides were heated with various spinels and oxides. In general, spinels of the series CuO R2O3decomposed to the compound CU2O R2O3with the liberation of R2O3, when R was Al3+, Cr3+, or Fe3+. With magnesia, cupric oxide formed the mineral güggenit, CuO–MgO, which during heating decomposed with the evolution of oxygen to MgO and Cu

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15360.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

As a preliminary to the investigation of the ternary systems Li2O‐B2O3‐P2O5and Li2O‐SiO2‐P2O5the existence of the previously reported lithium ortho‐, pyro‐, and metaphosphate compounds was confirmed. A rapid, reversible inversion takes place in Li4P2O7at 630°C. New data on the melting points, optical properties, and X‐ray diffraction patterns of each of the compounds

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15361.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Measurements were made of temperature and ternary composition for coexisting liquid and crystalline phases on the air isobar in the system Fe2O3‐Fe3O4‐YFeO3with particular regard to the stability range and compositional limits of yttrium iron garnet. Phase equilibrium relations were determined by conventional quenching techniques combined with measurements of loss in weight at the reaction temperature to locate true ternary compositions. The intersection of the air isobar with the ternary univariant boundary curve for coexisting magnetite, garnet, and liquid phases results in a eutectic‐type situation at the composition Y0.27Fe1.73O2.87and 1469°± 2°C. A similar intersection of the isobar with the boundary curve for coexisting garnet, orthoferrite, and liquid phases gives rise to a peritectic‐type reaction at 1555° 3°C. and Y0.44Fe1.56O2.89The yttrium iron garnet crystallizing from liquids within these temperature and composition limits contains up to 0.5 mole % iron oxide in excess of the stoichiometric formula in terms of the starting composition 37.5 mole % Y2O3, 62.5 mole % Fe2O3. At 1470° C. the garnet phase in equilibrium with oxide liquid contains 2 mole % FeO in solid solution. The small solubility of excess of iron oxide and partial reduction of the garnet phase in air are unavoidable during equilibrium growth

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15362.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

The microwave properties of a number of polycrystalline mixed garnets have been studied. The compositions investigated included solid solutions of yttrium iron garnet with gadolinium iron, samarium iron, yttrium aluminum, yttrium gallium, and yttrium chromium garnets. Ball‐mill mixing techniques were employed in specimen preparation. Line width, saturation magnetization, and effective g‐factor measurements were made as a function of composition and temperature for all specimens studied. Curie temperatures were also measured for each specimen. The merits of using these garnet compositions for microwave component applications are amplified by the fact that some of their properties may be independently controlled. Data on temperature compensation and high‐power effects are presented as well as a discussion of the applicability of these materials to microwave solid‐state

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15363.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

A study has been made of the growth of barium ferrite single crystals from a sodium carbonate flux. Crystals weighing up to 5.6 gm. have been grown by cooling melts slowly from about 1250°C. The phase diagram of the system BaO‐Na2O‐Fe2O3has been studied in the region of the BaFe12O19composition. The effects of variations in batch composition, heating cycle, and seeding have been studied from the point of view of crystal yield and qua

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15364.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Subsolidus equilibrium relations in a portion of the system Li2O‐Fe2O3‐Al2O3 in the temperature range 500° to 1400°C. have been determined nearpo2= 0.21. Of particular interest in this system is the LiFe5O8‐LiAl5O8join, which shows complete solid solution above 1180°C. Below this temperature the solid solution exsolves into two spinel phases. At 600°C. approximately 15 mole % of each compound is soluble in the other. The high‐temperature solid solution and the low‐temperature exsolution dome extend into the ternary system from the 1:5 join. There is no appreciable crystalline solubility of LiFeO2or of α‐Fe2O3in LiFe5O8. An attempt to confirm HFe5O8as the correct formulation of the magnetic ferric oxide “γ‐Fe2O3” was inconclusive, but in the absence of positive evidence, the retention of γ‐Fe2O3is recommended. All the metallic oxides of the Group IV elements increase the temperature of the monotropic conversion of ‐γ‐Fe2O3to α‐Fe2O3. Silica and thoria have a greater effect on this conver

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15365.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

A glass scintillator which can be used as one of the main components of a slow‐neutron time‐of‐flight spectrometer has been developed. This sodium aluminoborate glass containing 73 mole % B2O3and 8.0 mole % Ce was melted under highly reducing conditions in a series of cerium‐activated very high boron‐containing glasses. This glass is water white with very high light transmittance for wave lengths greater than 3800 a. u. It has a neutron‐detection efficiency which is 25 to 30% greater than any other known glass scintillator in the energy range 102to 104e.v. and is considerably better than any other type of detector. It was found that the neutron pulse height increases with increasing cerium content up to a maximum and then decreases with further increases in the cerium content. The molar content of cerium required to obtain a maximum pulse height for each B2O3concentration increases linearly with the increase in the B2O3content. However, the maximum pulse height decreases gradually with the B2O3content from 17.0 arbitrary units at 54.5 mole % to 6.7 at 73.4 mole %. This lower pulse height is still considerably above the photomultiplier noise at room

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15366.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Deflocculation of suspensions results from the formation of surface charges on particles. The strongest charges are obtained by the hydrogen bonding of polar ions or molecules on particle surfaces. Measurements were made of the deflocculation of alumina in both polar and non‐polar liquids using various acids, bases, and electrolytes. The pH of suspensions was found to be temperature‐dependent, the pH decreasing with increasing temperature. The results of these experiments are not compatible with the double‐layer theory for the deflocculation of suspensions. The polar‐screen theory explaining deflocculation by the hydrogen bonding of polar ions or molecules to electronegative surfaces is presented. The polar ions or molecules provide the surfaces with a charged screen. Predictions are made on the basis of this theory and are experimentally v

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15367.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

The formation of Cr3O8, Cr2O5, CrO2, and Cr2O3by the decomposition of anhydrous CrO3under a high oxygen pressure and their physical and chemical properties are presented. The crystal structure of CrO2is a rutile type and its lattice constants do not vary with the ratio O/Cr. The specific gravity of CrO2decreases with an increase in the ratio O/Cr. This is explained by assuming that the crystal structure of CrO2contains an excess of Cr ions at interstitial sites. This crystal model is supported by the low electrical resistivity of CrO2. An electron microscopic examination showed an abnormal grain growth of CrO2during the decomposition of Cr2O5to CrO2. The activation energies of the decomposition of Cr2O5and CrO2to Cr2O3in air are 61.7 and 48.2 kcal. per mole, respectively. The pressure‐temperature diagram of various chromium oxides has been determined. From the pressure‐temperature curve of CrO2‐Cr2O3the heat of decomposition is found to be 26.3 kcal. per

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1961.tb15368.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY