ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12554.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Research studies have resulted in the development of an oxygen‐deficient zirconia material modified in a novel way to make it thermally stable and inert to molten titanium. It is possible to melt titanium in crucibles of this material with no significant increase in hardness. However, limitations regarding overheating and soaking must be taken into accoun

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12555.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Phase equilibria in the binary system BaTiO3–SrTiO3were studied above 1200°C. This system is characterized by a complete series of solid solutions with a minimum at 2.5 mole % SrTiO3and 1585°C. The hexagonal BaTiO3phase is suppressed to a region extending no farther than 0.5% SrTiO3at 1600°C. No immiscibility gap was f

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12556.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Sapphire single crystals exhibit the same qualitative creep properties over the temperature range 900° to 1400°C. as do comparable metal single crystals at room temperature. The creep of sapphire under constant load has four portions: (a) a period of increasing creep rate, (b) a period of decreasing creep rate, (c) a period of constant creep rate, and (d) a final period of increasing creep rate. The stress required to initiate creep falls smoothly from about 780 kg. per sq. cm. at 900°C. to about 130 kg. per sq. cm. at 1400°C. After creep is initiated, it will continue at a lower stress (the addition of chromia increases the stress required to initiate creep). The electrical resistivity of sapphire is apparently increased by plastic deformation and decreased by subsequent heating near 1800°C. Slip lines in periclase and rutile were studied and slip systems were identi

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12557.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

The chief problems in glazing alumina bodies at high temperatures are (1) high porosity of the body with high capacity for absorption at the glaze‐fusion temperature, (2) difference in thermal expansion between body and glaze, and (3) chemical activity of body and glaze materials. It is preferable to use feldspathic glazes with the RO group composed of alkalis from high‐potash feldspars augmented if necessary by small amounts of potash frits. The effects of varying alumina and silica, with the RO group composed entirely of alkali, are illustrated for a typical glaze field. The glazes were applied to four alumina bodies containing 0 to 30% clay. The specimens were fired to cone 18, one‐fire and two‐fire. The results show that the area of best glazes was centered around 1.0 RO, 1.5 Al2O3, 15.0 SiO2and 1.0 RO, 1.75 Al2O3, 15.0 SiO2for one‐fire and two‐fire glazing, r

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12558.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Experiments are described which show the effects of solution temperature, concentration, container material, and specimen position on the rate of dissolution of sheet‐steel and cast‐iron enamels by alkaline solutions. The results indicate that in designing apparatus to measure such corrosion rates the solution temperature should be controlled to at least ±0.1°C., that no glass parts of the apparatus should be exposed to the solution, and that, in the absence of stirring, consideration should be given to the positioning of the specimens. Corrosion test apparatus is described which was designed to meet these require

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12559.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Diffusion coefficients for bulk diffusion of argon in a potassium‐lime‐silica glass have been determined at temperatures in the range 308° to 470°C. by a radioactive counting technique. Argon diffusion was found to follow classical bulk diffusion theory within the limits of experimental accuracy. From a plot of logDversus 1000/T, an activation energy of 42 kcal. per mole was obtained for the argon diffusion process. The activation energy and diffusion coefficients obtained for argon by the radioactive counting technique are compared with values for helium and argon obtained by other investigators by use of the permeation tech

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12560.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY