ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1971.tb12220.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

The magnetic behavior of β‐NaFeO2precipitated in compositions along the Na2SiO3‐Fe2O3join of the Na2O‐Fe2O3‐SiO2system is reported from magnetic susceptibility data and Moessbauer studies. The anomalous magnetic properties observed are discussed in terms of the possibility of the presence of super‐par

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1971.tb12221.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

The free energy change for the reaction RuO2(s)+4Cu(s) = 2Cu2O(s)+Ru(s) was determined from 600° to 1000°C from emf measurements on a solid oxide galvanic cell using a stabilized ZrO2electrolyte. The cell was designed to minimize the reduction of RuO2by the gas phase. The results were used to develop an equation for the standard molar free energy of formation of RuO2:The standard molar enthalpy and entropy of formation of RuO2at 298°K were calculated to be −72,430 ±200 cal/mol and –40.44±0.2 eu, respectively, using the available heat capacity data. The absolute entropy of RuO2at 298°K was calculated to be 15.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1971.tb12222.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

The effects of kiln atmosphere on a low‐maturing shale and a moderately refractory fireclay fired in a pilot shuttle kiln using natural gas were studied. Bricks were fired in both oxidizing and reducing atmospheres, with emphasis on variable water vapor concentrations. The chemical and physical benefits of proper atmosphere selection and control are shown. Kiln atmosphere influenced absorption, shrinkage, strength, scumming, lime popping, frost resistance, and temperature uniformity. Results indicate that firing techniques with rapid schedules and significant reductions in maturing temperatures are feasible without sacrificing product qualit

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1971.tb12223.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Color development of shale and fireclay bricks fired and cooled in various atmospheres was evaluated. Iron oxide is the primary colorant in most brick clays; the key to color development and control flexibility is control of the oxidation state and physical or mineralogical state of the iron in the brick, e.g. whether iron is present in a glassy phase, as free oxides, or in a more complex crystalline phase. The influence of H2O vapor on black core elimination was studied. Increasing H2O vapor concentrations in oxidizing atmospheres greatly accelerate the elimination of carbon by the water‐gas reaction. The improved burnout depends on the type of carbon in the raw material, since carbon must be present above the temperature at which the water‐gas reaction becomes effect

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1971.tb12224.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

The weight loss of Cr2O3in oxidizing environments (Po2= 1 to 10−3atm) at 1200°C was measured. Both hot‐pressed and sintered Cr2O3pellets were investigated in O2/Ar gas mixtures, and the dependence of the weight loss on the O2partial pressure, the gas flow rate, and the total pressure was determined independently. The experimentally determined O2partial pressure dependence (rate ∝ PO23/4) corresponds to that expected for the reaction Cr2O3(s)+3/2O2⇌2CrO3(g). The flow rate and total pressure dependencies show that mass transport through a gaseous boundary layer is the rate‐controlling step in the oxidation/vaporization of Cr2O3. Evaporation coefficients for the loss of CrO3(g) under the experimental conditions

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1971.tb12225.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

The emf method was used to determine the lower limit of oxygen activity for essentially pure anionic conduction in Th0.85Y0.15O1.925from 775° to 1000C. The results show that the oxygen transference number is ≥0.99 when logPO2≥−6.5(104/T

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1971.tb12226.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

Complexes of dicalcium silicate and lithium, sodium, and potassium fluorides were prepared by solid‐state reactions. X‐ray diffraction powder pattern data are presented for the complexes. Phase transformations were found below 1000°C for the Li and K complexes, but not for the Na complex. The inversion point for the Li complex is between 915° and 920°C and that for the K complex is between 805° and 810°C. Between 940° and 950°C the Li complex fuses to a colorless glass‐like melt which on cooling shows evidence of partial conversion to

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1971.tb12227.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

X‐ray diffraction powder patterns were used to determine the cell constants for the complexes 2CaO·SiO2·LiF and 2CaO·SiO2·KF by Lipson's method of indexing, assuming orthorhombic structures. The resulting cell constants are α0= 18.2, b0=20.6, and c0=7.2 Å for the Li complex and α0=18.7, b0=20.5, and c06.9 Å for the

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1971.tb12228.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

A procedure is described for determining the stress profile in a plate from length changes during etching. Data for a tempered glass plate and an ion‐exchanged glass‐ceramic are gi

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1971.tb12229.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY