THERMAL STUDIES OF METAL-FILMS PREPARED WITH OXYGENATED SOLVENTS .12.
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1994
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Abstract
Copper, silver and gold colloids have been prepared by Chemical Liquid Deposition (CLD) with dimethoxymethane, 2-methoxyethyl ether and ethylenglycol dimethyl ether. The metals are evaporated to yield atoms which are solvated at low temperatures and during the warm up process colloidal sols with metal clusters are obtained.
Evaporation of the solvent was carried out under vacuum generating metal films. These films are showing very low carbon/hydrogen content and were characterized by elemental analyses and infrared spectroscopy.
The thermal stabilities of these metal films have been studied by thermogravimetry (TG) between 25 and 550-degrees-C under nitrogen flow. The decomposition temperature was obtained from the maximum of the first derivative from TG curve. The kinetic parameters of the thermal decomposition were determined by the Arrhenius equation. All these films degrade in a single step. The kinetic data thus obtained show that the thermostabilities decrease in the order: Au-DMM > Au-EDE > Cu-DMM > Cu-EDE > Ag-EDE > Ag-DMM > Au-2-MEE > Ag-2-MEE > Cu-2-MEE.
The thermal stability seems to depend on the metal and on the size of the ligand.
The decomposition reaction order is zero for Au, Ag-DMM and Au-EDE. However, n = -0.25 was obtained for the other films. This means that we are in the presence of a multistep decomposition mechanism. The pre-exponential factor, the reaction order, the decomposition temperature and the activation energy of the decomposition reaction for Ag, Au and Cu films have been determined.
Evaporation of the solvent was carried out under vacuum generating metal films. These films are showing very low carbon/hydrogen content and were characterized by elemental analyses and infrared spectroscopy.
The thermal stabilities of these metal films have been studied by thermogravimetry (TG) between 25 and 550-degrees-C under nitrogen flow. The decomposition temperature was obtained from the maximum of the first derivative from TG curve. The kinetic parameters of the thermal decomposition were determined by the Arrhenius equation. All these films degrade in a single step. The kinetic data thus obtained show that the thermostabilities decrease in the order: Au-DMM > Au-EDE > Cu-DMM > Cu-EDE > Ag-EDE > Ag-DMM > Au-2-MEE > Ag-2-MEE > Cu-2-MEE.
The thermal stability seems to depend on the metal and on the size of the ligand.
The decomposition reaction order is zero for Au, Ag-DMM and Au-EDE. However, n = -0.25 was obtained for the other films. This means that we are in the presence of a multistep decomposition mechanism. The pre-exponential factor, the reaction order, the decomposition temperature and the activation energy of the decomposition reaction for Ag, Au and Cu films have been determined.