Open menu
Nanowerk

Nanotechnology General News

The latest news from academia, regulators
research labs and other things of interest

New nanoalloys for high temperature soldering

(Nanowerk News) Removing lead from manufacturing processes and products is high priority for the EU. A European research programme has tackled the problem of high-temperature solders used in the electronics industry.
On soldering components on a printed circuit board, it is crucial that the joints do not remelt in subsequent soldering operations. The electronics industry is therefore inclined to use solder material containing a high percentage of lead with a higher melting point (300 C and above).
One solution is to use so-called nanosolders based on tin-antimony (Sn-Sb) alloys. Nanoparticles have a lower melting point than the bulk substance. Funded by the EU, the project 'A chemical approach to lead-free nanosolders' (Nanosold) aimed to develop new lead-free high-temperature solders with Sn-Sb-M alloys. M is silver (Ag), copper (Cu) and nickel (Ni).
Concentrating on the two ternary alloy systems Sn-Sb-Ag and Sn-Sb-Cu, the Nanosold project investigated the thermodynamic properties, the sum of the features of the individual phases. The team used the so-called 'Computer coupling of phase diagrams and thermochemistry' (Calphad) method enabling the scientists to reliably predict the thermodynamic properties without experimental information.
To refine the phase relations in the Sn-Sb-Ni system, Nanosold used other complementary methods. These included powder X-ray diffraction, electron probe micro-analysis, scanning electron microscopy and differential thermal analysis.
A reduction in melting point of up to 11 C was achieved using nanoalloys rich in Sn prepared by a chemical reduction method. Particle size was modified to be in the range of 50 to 150 nm which would translate into a size-dependent lowering of soldering temperature in any practical application.
Although there are further problems to be worked on, solder pastes based on nanoalloys would achieve a decrease in melting point. From an environmental point of view, the new nanoalloys remove a very toxic element from electronic appliances' manufacturing.
Source: Cordis
Subscribe to a free copy of one of our daily
Nanowerk Newsletter Email Digests
with a compilation of all of the day's news.
 
These articles might interest you as well: