ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11181.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

In a previous study of the constitution of lithium‐sodium‐potassium phosphate glasses slight but definite cationic effects were observed. The constitution of lithium‐rubidium phosphate glasses withn̄, the number average chain length, varying from 1.25 to 9.00 was determined by paper chromatographic methods to follow the effect of substituting the rather large rubidium ion (1.47 A) for the small lithium ion (0.68 A). Systematic changes were observed; these changes, however, were numerically small. With the increase in the rubidium substitution for lithium the pyrophosphate content of the glass decreased and the tripolyphosphate content increased. Glasses withn̄ values as low as 1.5 (Li/Rb = 1/1) could be made by quenching the platinum crucible containing the melt in water. Then̄= 1.25 glass, however, devitrified when thus made. It could be prepared only by the new copper‐block‐cooled strip furna

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11182.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

In a study of the interfacial reactions between SiO2and the refractory metals Ta, Nb, V, and Mo, a wide range of reactions was observed. Investigation of normal and tapered sections at the interface showed considerable reaction and solution in the case of V, reactions in the cases of Ta and Nb, and very little reaction in the case of Mo. The major interfacial reaction was oxygen corrosion followed by (most possibly) reaction with silica glass to form silicates. X‐ray data showed that the oxides were the principal components at the interface. Evidence was obtained for the formation of silicides in the case of the system Ta‐SiO2. A very low melting silicate was formed in the case of V and sil

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11183.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

A study was made of the decarburization of an Fe‐Ni‐Co glass sealing alloy in wet hydrogen and its effect on glass‐to‐metal sealing. Rods of this alloy were decarburized in wet hydrogen, and the decarburization process was found to be controlled by a diffusion mechanism whereDo=8.5 × 10‐3cm2per second andQ= 25.6 kcal per mole. The decarburized rods were then sealed with glass and the effects of the various decarburization treatments on glass‐to‐metal sealing were observed. These effects are described, and a decarburization schedule for productio

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11184.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Phase relations at liquidus temperatures in the system La2O3‐TiO2were studied in air. The existence of two previously unreported compounds, La2O3. TiO2and 2La2O3‐TiO2, is postulated on the basis of X‐ray and microscopic examination of crystalline samples, and in the case of La2O3.‐TiO2, on a maximum in the liquidus curve at that composition. Quenched liquids of the primary‐phase field of rutile were found to be semiconducting. This property was related to oxygen loss from both liquid and crystalline phases and is discussed in the light of weight loss experiments, microscopic examination of quenched samples, and information obtained from the literature. Dielectric constant and loss factor of the compounds La2O3‐TiO2, La2O3‐2TiO2, and 2La2O3‐9TiO2are reported at 1 Mc over the temperature ran

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11185.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Phase relations in the binary system between SiO2‐P2O5and SiO2were investigated by the quenching method using sealed platinum tubes to prevent the loss of P2O5. The compound Si02‐P2O5exists in two forms, the low‐temperature β form inverting sluggishly but reversibly to the high‐temperature β form at 1030°C. The β form melts congruently at 1290°C. The compound 2SiO2‐P2O5melts incongruently at 1120°C to a silica‐rich liquid and SiOa‐P2O5. In the region between 5 and 25 mole % PO2, reactions were so sluggish that no data could be ob

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11186.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

A direct electron‐optical method of observing an insulator surface is described and applied to a series of alumina ceramics. The surface of the object requires no previous treatment of any kind, and a resolving power of 2000 A has been obtained with a depth of focus of about 50p. Different phases and components can be distinguished. Fractured surfaces, a fault region, and polished surfaces of various alumina ceramics are examine

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11187.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

The natural and autoclave moisture expansions of a fired clay containing kaolinite, hydrous mica, and quartz were studied. A relation was established between the two expansions, which, together with a moisture‐expansion peak at about 1000°C, is explained in terms of the poorly crystalline and noncrystalline phases developed during firing. When low‐fired specimens that were exposed to moisture were desorbed by re‐firing, the shrinkage that accompanied the loss of moisture was interrupted by an expansion at about 5OOOC. This expansion depended on the firing temperature and probably was caused by the dehydroxylation of hydrous mica regenerated from mica anhydride by moisture sorbed after firing. In the case of specimens fired above the moisture‐expansion peak, the moisture responsible for expansion must be held in much the same way in the natural and in the autoclaved specimens. A study of the kinetics of moisture expansion showed a linear relation between the magnitude of expansion and the log of time for the period during which the specimens were exposed to moisture in the air. A similar relation existed for specimens fired from 1000° to 1150°C and autoclaved from 2 to 200 hours. It is further shown that it was possible, using preexisting data, to estimate, from the magnitude of expansion after a short period, the expansion to be expected at any time within the period to which the preexisting dat

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11188.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Hot‐pressing powdered magnesium fluoride resulted in a polycrystalline compact with essentially the density and transmittance of a single crystal. Compacted powdered MgF2was heated to 650°C and held under a pressure of 30,000 psi for 15 minutes. The starting material had to be free from impurities which would form a second phase, and the presence of water and bound hydroxyl groups had to be minimized. Overheating caused the starting material to resist hot‐pressing. It is postulated that mechanical bulk decrease was followed by plastic deformation during pressing and that both solid and surface diffusion of material took place to complete the coalescence of the gr

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11189.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

The dislocation structure in plastically deformed single crystals of corundum (α‐A12O3) was studied by etching and optical techniques. A special method of deformation was used which encouraged the participation of both the basal (0001), (1120) and the prismatic (1210), (1010) slip systems concurrently. This deformation resulted in highly stressed crystals which fractured spontaneously once the outside surface was scratched. Incoherent surface like imperfections, accompanied by distinctive dislocation arrays, were found embedded in the deformed crystals. These “surfaces” appeared as discontinuities, on each side of which dislocations etched differently. A possible origin of observed failure making use of the dislocation reaction ± [1010] = 3=1/3[2110]± 1/3[1120] is suggested. A mechanism for the observed strain hardening in prismatic bending is p

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11190.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY