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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Oxidation of metals 1 (1969), S. 73-91 
    ISSN: 1573-4889
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The interaction between gaseous oxygen and the surface of pure nickel oxide and NiO doped with Li2O was studied by means of work function measurements. It was observed that at low oxygen pressures in measurements carried out with a constant amount of the gas in the reaction chamber, rather than carried out at constant pressure, at the temperatures corresponding to the adsorption equilibrium, the work function initially increased and then decreased. It was concluded that this complex character of the observed work function changes versus time is due to the superimposition of two parallel effects, i.e., charging of the NiO surface during oxygen chemisorption and simultaneous discharging of this surface by diffusion of ions from the bulk. On the basis of the electric model of the NiO surface covered with adsorbed oxygen, a quantitative interpretation of the above processes was proposed and a kinetic equation was given. The proposed kinetic equation was solved with the aid of an analog computer, and good agreement between the experimental curves and the kinetic equation was obtained.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 155 (1959), S. 453-464 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Zusammenfassung Die Ergebnisse der Leitfähigkeitsuntersuchungen von polykristallinem ZnO im Temperaturbereich 100 bis 700° C unter verschiedenen Bedingungen des Druckes werden angegeben. Nach der Meinung der Autoren wird im Temperaturbereich über 450° C die Temperaturabhängigkeit der Leitfähigkeit durch die Änderungen des Gleichgewichtzustandes der O2-Chemisorption auf der Oberfläche von ZnO bestimmt. Bei 450° C wird die Chemisorptionsgeschwindigkeit gleich Null und deshalb ist bei niedrigeren Temperaturen das Oberflächengleichgewicht schon „eingefroren“. Die Temperaturabhängigkeit der Leitfähigkeit entspricht dann der thermischen Aktivierung von Donatoren. Infolge des in der Randschicht entstehenden Potentialgradienten können die Zwischengitterzinkionen bei Zimmertemperatur in der Richtung der Oberfläche diffundieren, wobei das Gitter angebaut wird. Dieser Prozeß ist als Ursache der zwischen 20 bis 450° C festgestellten irreversiblen Leitfähigkeitsänderungen anzusehen.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 10 (1975), S. 857-862 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Measurements of the kinetics of evaporation of Li2O from polycrystalline solid solutions of Li2O in NiO have been performed under varying temperatures (1340 to 1665 K) and solution concentrations (0.25 to 19.5 at.% Li). By taking into account the changes in specific surface area during annealing of the preparations, an equation has been derived describing the kinetics of the evaporation process.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 8 (1973), S. 545-558 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract On the basis of high-temperature studies of electrical conductivity of poly- and monocrystalline nickel oxide and making use of the results of studies on chemical diffusion coefficients obtained by several authors and in the present work, the structure of point defects in nickel oxide has been considered. It has been shown that in the temperature range 900 to 1300° C and at the oxygen pressure from 10−4 to 1 atm there occur in nickel oxide singly- and doubly-ionized cationic vacancies in comparable quantities. Assuming such to be the model of defect structure in Ni1−yO, the equilibrium concentration of cationic vacancies as a function of temperature has been calculated for the oxygen pressure of 1 atm. It has been shown that the results obtained are in good agreement with the results of direct determinations of concentration of cationic vacancies in NiO.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 294 (1958), S. 269-281 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Abhängigkeit der elektrischen Leitfähigkeit von ZnO + Cr2O3-Mischungen (im Molverhältnis 1:1) von den Bedingungen des vorhergehenden Erhitzungsprozesses wurde untersucht. Es wurden ferner Messungen der Abhängigkeit der Leitfähigkeit vom Sauerstoffdruck durchgeführt. Die Ergebnisse werden interpretiert.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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