ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb13503.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

The tangential deflection was measured on glass‐steel strips that were heat‐treated below, as well as in, the transition zone of the glass. The change in tangential deflection after heat‐treatment was similar to the change in flexure breaking stress, thermal‐shock resistance, resistance to' fish scaling, and spalling of glass in an acid environment after heat‐

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb13504.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.tb13505.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.tb13506.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.tb13507.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.tb13508.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

An investigation of the ternary systems BaO‐TiO2‐SnO2and BaO‐TiO2‐ZrO2led to the discovery of two new compounds belonging to the system BaO‐TiO2. These compounds, Ba2Ti9‐O20and Ba2Ti9O20, are stabilized by minute additions of SnO2or ZrO2. The known compound BaTi2O5can be obtained only from the molten phase and decomposes below 1300°C. into Ba2Ti5O12and BaTiO2. In these systems no ternary compounds are found. The ternary phase diagrams can be divided into regions with high and low dielectric losses, which are in accordance with the phase relations. Tables with crystallographic data of the new compounds

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb13509.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

Electron micrographs and electron diffraction patterns of chemically pure and natural magnesite samples heated from 400° to 1050°C. were obtained and interpreted. It was found in general that at lower temperatures (400° to 600°C.), small MgO particles were formed by the decomposition of MgCO3(MgO + CO2). As temperatures were increased (600° to 800°C.), these particles grew into large secondary aggregates showing higher porosity. The porosity of the main particles (unchanged MgCO3) also increased. Sintering began at 850° C., and the particles seemed to adhere more strongly to each other and aggregation and porosity decreased. Sintering was completed at 1050°C., and sharply defined cubic crystals were observed in large numbers varying in size from 0.1 to 0.35 μ. In natural magnesites that contained traces of iron and aluminum oxides the decomposition began at higher temperatures than in the chemically pure samples, but the recrystallization process was delayed, which is contrary to expe

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb13510.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

The results of an investigation of densification and grain growth during the sintering of high‐purity NiO in various atmospheres are presented. The sintering of NiO powders is divided into three stages. Grain growth during the third stage follows the empirical equationD2=Kt, whereDis the average grain diameter,Ka rate constant,tthe sintering time. The activation energy of grain growth was found to be 55 kcal. per mole. The shrinkage and weight loss during the sintering process in vacuum were larger than in argon, air, and oxygen. Grain growth during sintering also differed with the sintering atmosphere. It was concluded that the sintering process is not explained reasonably by the theory of a semiconducto

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb13511.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

The effect of transition metal, alkali, alkaline‐earth, and heavy metal oxide additions on the sintering of magnesia was determined by measuring bulk density and shrinkage. Polished specimens were made on selected compositions and the grain structure was photographed. The unusual effect of titanium, zirconium, silicon, lithium, iron, and zinc oxides in promoting high sintered densities is explained on the basis of the defective crystal structure produced by these addition

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb13512.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY