ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb15446.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

The thickness of oxide layers formed on enameling iron at short times was measured as a function of temperature to compare the effects of three pretreatments: (1) sulfuric acid pickle, (2) nickel flash, and (3) phosphate coating. The oxides present were examined by X‐ray diffraction and metallographic techniques. Nickel‐flashed specimens exhibited lowered oxidation rates. The phosphate coating produced significantly rougher metal‐oxide interfaces under the process conditions

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb15447.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

Solid‐state reactions between Li2O and Al2O3were studied in the region between Li2O.Al2O3and Al2O3. The compound Li2O Al2O3melts at 1610°± 15°C. and undergoes a rapid reversible inversion between 1200° and 1300°C. Vaporization of Li2O from compositions in the system proceeds at an appreciable rate at 1400°C, as shown by fluorescence. Lithium spinel, Li2O ‐5Al2O3, was the only other compound observed. The effect of Li2O on the sintering of alumina was inv

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb15448.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

The crystal structure and thermal expansion of titanium carbide, nickel, and two titanium carbide‐base cermets were determined between room temperature and 1100°C. (2012°F.). No structural changes were observed. An abnormal rate of expansion was observed for pure nickel near the Curie temperature, 353°C. (665°F.), and for the nickel and carbide phases in the cermets at about 816°C. (1500°F.). The expansion coefficient of pure nickel and the nickel phase in the cermets was found to be approximately twice that of pure titanium carbide and the carbide phase in the cermets. The brittleness and poor impact strength of the cermets was attributed to the large residual stresses present in these materials as a result of this difference in thermal expansion. The stress‐strain relations were interpreted on the basis of a mechanical interaction between the phases in the cermets. The carbide phase was found to be essentially under triaxial compression and the nickel phase under a triaxial tension of 158,000 lb. per sq. in. At elevated temperatures, increased solid solubility of carbide in the nickel phase and plastic deformation of this phase was believed to influence the stress‐strain relations and the thermal‐expansion behavior of the phases. It was concluded that replacement of the nickel phase in the cermets with a metal or alloy, such as a nickel‐chromium‐molybdenum alloy, which has a coefficient of thermal expansion similar to the carbide phase in the cermets, would improve the impact strength of these bodies. Equations were developed for the thermal expansion of titanium carbide and nickel. Values of the expansion coefficient were computed for each of the materials by differentiation o

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb15449.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

A general procedure is presented whereby all the internal stresses in a glass cylinder can be calculated from birefringence observations. The method applies to circular cylinders, either rods or tubes, where the stress distribution may be any arbitrary function of the radial coordinate and where the observation path is far enough from the ends of the cylinder so that end effects are negligible. The method is applied to an oil‐tempered solid glass rod and the calculated stress is compared with that expected from a constant cooling rat

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb15450.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

A factorial design of experiment is one in which a variable is evaluated at all levels of all other variables. This type of experiment was applied to the unit operations in body preparation and forming by extrusion. Drying and firing unit operations were not considered, and the variance due to these operations was minimized by duplication. The variables or factors were (1) particle‐size distribution at three levels, (2) water of plasticity at two levels, (3) entrapped air at two levels, and (4) two replications. Analysis of variance was used to determine the significant effects. It was found that 95%.0f the total variance of the drying shrinkage was accounted for by the particle‐size distribution, water of plasticity, and two interactions; 95% of the total variance of the dry modulus of rupture was accounted for by particle‐size distribution, water of plasticity, entrapped air, and two interactions; 52% of the total variance of the firing shrinkage was accounted for by the particle‐size distribution; 87% of the total variance of the fired modulus of rupture was accounted for by the particle‐size distribution, water of plasticity, entrapped air, and three interactions. Since a tunnel kiln makes it possible to control the firing operation closely and with no changes in composition, close control of the particle‐size distribution, water of plasticity, and entrapped air should make it possible to produce more uniform ware. The slope constants for the factors were also determined which show the most efficient path leading to the development of optimum conditions necessary for maximizing a desir

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb15451.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb15452.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY