ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1964.tb14630.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Thermodynamic works of adhesion between a porcelain enamel and gold, platinum, palladium, graphite, and a gold‐base metal alloy were determined from surface‐tension and contact‐angle measurements. Theoretical shear strengths in the order of 80,000 psi were calculated from these data. Mechanical strength tests indicated values, however, of only 3000 to 10,000 psi for these interfaces. Wetting forces were therefore strong enough to account for the observed interface strengths. The strengthening effect of metal oxides on the bond strength is discussed in terms of the polarization and dislocation the

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1964.tb14631.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Large (10 to 20 g) macroscopically sound ZnO crystals suitable for preliminary transducer and other studies have been grown hydrothermally at rates of from 10 to 15 mils per day. The factors found to be important in achieving good growth were (1) base concentration of growth solution, (2) temperature difference between dissolving and growth regions, (3) presaturation of growth solution, (4) warm‐up procedure, (5) addition of Li+ to the growth solution to suppress dendrite formation, (6) etching to remove seed damage, and (7) nutrient size. Each of the foregoing factors was studied and is discusse

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1964.tb14632.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Single crystals of hexagonal ferrites up to 1/2 in. long were grown from the system NaFeO2‐Fe2O3‐BaO‐MeO, where Me = divalent Zn, Co, Ni, or Mg. NaFeO2was the flux from which crystals were grown in platinum crucibles from a maximum temperature of 1250° to 1375°C. More than 150 single‐crystal growth experiments were attempted and the reaction products were studied by X‐ray diffraction and optical microscopy. Stability data for the principal single‐crystal products are given for initial compositions lying in quaternary planes. Such planes were considered for BaO/MeO ratios corresponding to the compounds 1/1 for Ba2Me2Fe12O22(Y)and Ba2Me2Fe28O46(X), 3/2 for Ba3Me2Fe24O41(Z), 2/1 for Ba4Me2Fe36O60(U), and 1/2 for BaMe2‐Fe16O27(W)(Me = Zn, Co, Ni, or Mg). A number of adjoining planes were also considered. All the five known structure types were grown as single crystals. A series of four new hexagonal ferrite structures was discovered. These were derived fromZby systematically adding blocks ofY.Magnetization as a function of temperature and field was investigated for crystals of two structure types. The room‐temperature ferromagnetic resonance and effective anisotropy were studied for substituted crystals of the same tw

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1964.tb14633.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Electrochemical cells using the oxygen electrode reactions of Förland and Tashiro were constructed from soda aluminosilicate glasses (containing up to 34.8 wt% alumina) and sodium silicate glasses. The emf developed by these cells was measured as a function of temperature. The relative acidities of the glasses, as indicated by the activities of the soda, increased with increasing alumina content, the rate of change increasing when the Al/Na ratio reached 1. The entropy change for the cell reaction went through a maximum. These properties are correlated with the measurements of, and the structural model used in, the previous three parts of this series. Measurements were made to show that the emf values obey an additive relation

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1964.tb14634.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

The effect of inorganic surface treatments on the orientation of lithium disilicate crystals formed in Li2O·2.75SiO2glass fibers was studied. Glass fibers 0.5 mm and 9μ in diameter were subjected to various surface treatments at room temperature and then heated between 550O and 800°C. It was observed that metal salt solutions applied to the fiber surfaces at room temperature decreased the degree of orientation during heating only if the metal entered the glass and formed nucleation sites within the fibers. Orientation could also be decreased by removing lithium from the glass surfaces. Comparison of the crystallization characteristics of untreated and AgNO3‐treated fibers indicated that the crystallization behavior was controlled by either a growth process or a nucleation process, depending on whether the temperature was below or above 625°, respect

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1964.tb14635.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

The liquidus, solidus, and subsolidus in the system MgO‐MgCrz04 were redetermined. Petro‐graphic studies indicated that 47 wt% Cr203 could enter into the periclase lattice at about 235OO C. X‐ray and optical data showed that the solid solution decreased to 32 wt% Cr202 at 2165OC, 11 wt% at 1600°C, 5 wt% at 1400°C, 2.5 wt% at 1200°C, and 0 wt% at 1000°C. Petro‐graphic studies also suggested that picrochromite could contain about 5 wt% MgO in solid solution. The liquidus was much higher than has been indicated on previously published phase equilibri

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1964.tb14636.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Magnesium uranate was prepared by standard solid‐state synthetic techniques. Decomposition pressures were measured between 1000° and 137OOC. At oxygen contents less than MgUO3.5a solid solution of fluorite structure was found. Above MgUO3.75the orthorhombic magnesium uranate phase was observed. The two phases were in equilibrium in air at 126OOC. The heat of solution of O2in the fluorite phase was 45 kcal mole−1and the heat of the reaction MgUO3.5+ 0.12O2→ MgUO3.75was 83.3 kcal mole

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1964.tb14637.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Measurements of the rate of dissolution of single crystals of sapphire in molten CaO‐A12O3‐SiO2slag from 1340° to 1550°C under conditions of molecular diffusion, free convection, and forced convection reveal that the rate of dissolution was controlled by transport in the molten silicate. The results were self‐consistent in that the independently calculated apparent binary diffusion coefficient agreed well for all three cases. This binary diffusion coefficient at temperatures above 1450°C coincided remarkably well with that of the tracer diffusion coefficient for the silicon ion. For a number of reasons the significance of this agreement should not be overe

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1964.tb14638.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

The reactions between boron and phosphorus to form the boron phosphides are described. The elements were compacted into pellets and dropped into a preheated reaction zone. The reaction between zinc phosphide and boron also resulted in the formation of the boron phosphides and the complete removal of zinc in the vapor phase. Cubic BP formed initially and decomposed into the rhombohedral B13P2above 1130°C. The formation of B13P2by decomposition of BP was rapid and complete at 1600°C. Some properties of BP and B13P2 are summarized. The B13P2formed by decomposition was a very fine powder and large crystals were grown in metallic melt

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1964.tb14639.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY