Jiří Buršík, J. Sopousek, J. Zalesak, Vilma Buršíková

Proc: ANALYTICAL ELECTRON MICROSCOPY OF LEAD-FREE NANOPOWDER SOLDERS

NANOCON 2010, 2ND INTERNATIONAL CONFERENCE (2010) pp.336-339

Published by TANGER LTD

During the last decade, the EU legislative regulations enforced lead-free solders and hence initiated an extensive search for the best replacement of lead-containing solders. Parallel to new binary and ternary bulk solders, metal nanoparticles are also considered as potential candidates for solder materials. It is known that physical, electric and thermodynamic properties of nanoobjects are significantly different from those of the bulk materials. The oxidation, high reactivity of the surfaces and aggregation are frequent problems of nanotechnology applications. The nanoparticles of pure metals and alloys exhibit the depression of the melting point compared to bulk material, hence they are able to aggregate and to form firm interlayer joints at low temperatures. Exploiting this effect can save energy, work and materials. In this work we study the quality of bulk materials produced of Ag nanopowders annealed at various temperatures. Ag nanoparticles were prepared by the chemical wet synthesis and studied in a transmission electron microscope. Sandwich structures were prepared of Cu disks and a layer of Ag nanopowder. The sandwiches were annealed in the range 200-350 degrees C, metallographic cross sections were prepared from annealed samples and the microstructure and quality of joints was studied by analytical electron microscopy and depth sensing indentation technique.

You may also contact one of the authors: vilmab@physics.muni.cz