Abstract
The initial sintering and gas release characteristics were examined for the slow oxidation treated Ag ultrafine powders. The sintering characteristics were examined by measuring the surface areas and the dimensional changes. The neck growth of the Ag ultrafine powders occurred at room temperature, and the densification occurred at temperatures above 473 K.
The released gases detected with a quadrupole mass spectrometer were mainly CO, CO2, H2O and H2. The peaks of these gases were observed in the neighborhood of 370, 480, 530, 620 and 710 K. These desorption peaks were explained as follows. (1) The peak at 370 K was the release of CO and CO2 produced by the reaction of adsorbed oxygen with surface carbon impurity. (2) The peak at 480 K was the release of CO2 due to the decomposition of the adsorbed surface carbonate CO3 (a). (3) The peak at 620 K was the release of CO, CO2, H2O and hydrocarbon accompanied with the decomposition of Ag2O. (4) The peak at temperatures above 710 K was the release of CO and CO2 by the reaction of sub-surface oxygen with surface carbon impurity.
