One‐step Preparation of Nanosized Ag‐Pd Co‐powder and its Alloy Formation at Low Temperature

Nano‐sized silver‐palladium co‐powder has been synthesized from silver nitrate‐palladium chloride by wet chemical method. The present experimental conditions are applied for the first time for Ag‐Pd co‐powders wherein sodium formaldehyde sulfoxylate (SFS) has been used as an external reducing agent to simultaneously reduce respective metal salts. SFS reduces the metal salts at room temperature thus prevents formation of bigger particles of the respective metals in co‐powder. Powder X‐ray diffraction measurements (XRD) and Transmission electron microscopy (TEM) suggest the formation of nano‐sized Ag‐Pd co‐powder with particle diameter in the range of about 25 nm. SEM shows that the powder morphology changes with temperature. Heat treatment of 90:10 (Ag:Pd) composition showed shift in XRD peaks indicating alloy formation of Ag/Pd at lower temperature. Thick‐films generated by use of the co‐powder resulted in Ag/Pd alloy at about 500°C as confirmed by the XRD. Thermal analysis showed that Ag/Pd co‐powders initially gain the weight due to oxidation followed by the weight loss.

Keywords:

• Noble metal
• transition metal
• nano‐powder
• chemical synthesis
• alloy

We thank Department of Information Technology (DIT), Govt. of India, for financial support through grant no. 20(7) 2003VCND and Executive Director for encouragement. We thank Mr. S. Deshmukh for general assistance for experimental work.