0000000000739728
AUTHOR
Louis-c. Dufour
Zeolite-gas systems and solar refrigeration : a study of the adsorptive properties at high pressures in the R22 freon-13X zeolite and ammonia-13X zeolite systems
The adsorption of ammonia and R22 freon on 13X zeolite was studied in the conditions of possible use of these fluids in heat machines for solar refrigeration. The ranges of temperature and pressure, investigated in this study, extended from 0 to 80 °C and from 10-1 to 6 105 Pa respectively. The adsorption isotherms were collected by microgravimetry using a thermobalance specially built to be used in aggressive gases at pressures up to 106 Pa. Weak hysteresis was detected when ammonia was desorbed below 80 °C. A critical study concerning both applicability of classical adsorption equations (Dubinin-Radushkevitch and Langmuir) and comparison with other zeolite-gas systems is presented. Compar…
Small Particles and Thin Films of Metals on Ceramic Oxides
This paper is aimed at presenting some recent ideas and experimental results on characterization and properties of small particles and thin films of metals on oxide surfaces. Analysis is restricted to metallic films on well-defined surfaces, mainly monocrystalline surfaces and to ceramic oxides having a marked ionic character. The properties of metallic films obtained by chemical reduction of oxides and those of deposits are compared. Nucleation and growth modes are described. Interfacial properties are analysed in terms of size or thickness effect and in the general framework of the ceramic-metal bonding.