ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1963.tb13760.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Single crystals of beryllia have been grown by two methods. One method exploits the high‐temperature reversible reaction BeO + H2O.Be(OH)2. The other is a flux method, in which BeO is dissolved and precipitated as single crystals in a lithium molybdate flux. Characteristics and remaining problems of the two methods are discussed, and the crystals produced are describe

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1963.tb13761.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Linear thermal‐expansion data are presented for PbAl2O4, Pb2GeO4, PbMoO4, PbWO4, the perovskite‐type structures Pb2MgWO6, Pb2FeTaO6, and Pb3Fe2WO9, and the apatite‐type structures Pb5(SiO4)(VO4)2, Pb5(GeO4)(VO4)2, and Pb5(GeO4)(PO4)2. X‐ray powder data are given, and the behavior of the compounds is correlated with previous information from the lit

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1963.tb13762.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

The diffusivity of the oxygen ion in vitreous silica has been directly determined by exchange measurements employing the stable isotope18O and mass spectrometer analysis. It was found that over the temperature range 925° to 1225°C the results can be represented by the equationD= 1.51 × 10−2exp (‐71,200/RT) cm2sec−1. These results are compared with other measurements of oxygen diffusion in silicate glasses. It is proposed that the controlling diffusion step in silicate glasses and nonstoichiometric silica is the rupture of a single oxygen bond to silicon and that the diffusion mechanism is interstitial motion through voids in the lattice. An analysis of theoretical expressions for the pre‐exponential termDOshows that present theories are unable to predictDOfor oxygen diffusion in glasses. It is also shown that the mechanism for electrical conduction in vitreous silica or in electrolytically purified quartz is not migration of o

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1963.tb13763.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

A method of depositing oxide glass films on a substrate is presented. The method involves the sputtering of a metal or semiconductor electrode in an oxidizing atmosphere (so‐called reactive sputtering). The films obtained are of good quality, unstrained, and adhere well to the substrate. Films of considerable thickness can be deposited and the substrate need not be heated during the process. The preparation of lead tellurite glass films, silica and germania glass films, silicate glass films, and stannate glass films is described. Some data on the kinetics of film growth and on the physical properties of these materials are presente

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1963.tb13764.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Arsenic‐sulfur‐iodine glasses, recently described by Flaschenet al.,were prepared and exposed to various neutral, acidic, and alkaline solutions. Chemical durability, reported in terms of weight loss per unit of surface exposed, was correlated with glass composition, test temperature, exposure duration, and solution pH. Physical properties, such as density, melting temperature, deformation temperature, linear thermal expansion coefficient, and relative fluidity at melting and room temperatures, are also reported. These low‐melting inorganic glasses were found to exhibit excellent resistance to moisture and to acids, including hydrofluoric acid. On the basis of interpretation of the test data, the structure appeared to be a random arrangement of long‐chain sulfur and branched‐chain arsenic‐sulf

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1963.tb13765.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Potential nuclear fuels in the system UO2‐ZrO2‐CaO were investigated. Cubic fluorite‐type solid solutions, as indicated by X‐ray diffraction patterns, were formed by sintering U3O8‐CaO‐stabilized ZrO2compacts in either air or hydrogen. A continuous solid solution was found between urania and stabilized zirconia after sintering in hydrogen at 1750°C. Sintering in air produced a limited solid‐solution region in the stabilized zirconia portion of the system at 1450°C. Results on phase identification, oxidation behavior, and water corrosio

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1963.tb13766.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Melting relations in the systems CaO‐manganese oxide and MgO‐manganese oxide in air have been determined at temperatures up to 1705°C. In the system CaO‐manganese oxide four crystalline phases have stable existence in equilibrium with liquids: lime (approximate composition CaO‐MnO), spinel (approximate composition Mn3O4‐CaMn2O4), and two ternary solid solution phases in which Ca/Mn ratios as well as oxygen contents vary over considerable ranges. One of these ternary solid solution phases may for the sake of simplicity be represented approximately by the formula CaMnO3and the other by the formula CaMn2O4. Three isobaric invariant situations exist, with temperatures and phase assemblages as follows: At 1588°± 10°C the two crystalline phases lime and CaMnO3coexist in equilibrium with liquid (40 wt% CaO, 60 wt% manganese oxide) in a peritectic situation. Another peritectic at 1455°± 5°C is characterized by the equilibrium coexistence of CaMnO3, CaMn2O4, and liquid (25 wt% CaO, 75 wt% manganese oxide). A eutectic situation exists at 1439°± 5°C with CaMn2O4, spinel, and liquid (18 wt% CaO, 82 wt% manganese oxide) present together in equilibrium. In the system MgO‐manganese oxide in air periclase‐manganosite solid solution (approximate composition MgO‐MnO) and spinel (approximate composition Mn3O4‐MgMn2O4) are the only crystalline phases present in equilibrium with liquids. Liquidus and solidus temperatures increase with increasing MgO content. A peritectic situation exists at 1587°± 10°C, with the two crystalline phases coexisting in equilibrium with liquid (1 wt

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1963.tb13767.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Phase equilibria in the condensed system NaF‐ThF4‐UF4were determined by cooling‐curve and thermal‐gradient quenching experiments from the liquidus to ∼450°C. A phase diagram of the ternary system was constructed, showing three singular points and eleven invariant points, including two eutectics, occurring in association with the primary phases of ten solid solutions and two pure solids. The eutectic mixture having the composition 75.5NaF‐10.5ThF4‐14UF4(mole %) melts at 575°C, the lowest liquidus temperature in the system. Except for NaF, NaF‐ThF4, and ThF4‐UF4solid solutions, phases crystallizing from molten NaF‐ThF4‐UF4mixtures are solid solutions formed by interchange of U4+and Th4+ions in NaF‐ThF4and NaF‐UF4compounds. No ternary compounds were found. Phase diagrams of the systems NaF‐ThF4and NaF‐UF4, revised in the course of this study to include the newly identified phases, 7NaF.2ThF4and 7NaF.2UF4, are presented. X‐ray diffraction and optical data are given for the pure crystal phases, 4NaF.ThF4, 7NaF.2ThF4, 7NaF.2UF4, 3NaF.UF4, and for 3NaF.2ThF4‐5NaF.3UF4solid solutions. The system is unique among the fluoride systems reported in containing so wide a variety of substitutional solid solutions and in containing a continuous solid solution formed of binary compound pairs 3NaF.2ThF4and 5NaF.3UF4which are isomorp

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1963.tb13768.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

The cohesive and surface energies of thorium and uranium dioxides were estimated theoretically by computations based on a Born‐Mayer type of model. The sensitivity of the results to changes in the data used for the calculations is illustrated and discusse

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1963.tb13769.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY