IPC has published a set of recommended test protocols for new lead-free solder alloys as a White Paper. Harmonisation of technical comparisons between new alloys and the conventional SAC305 should help to remove uncertainties for customers.

Despite efforts, particularly in the US, to narrow the number of lead-free solder alternatives, there rather been an increasing proliferation of alternatives. These have largely been lower cost low-silver products with different dopants used to compensate for lower performance. Other developments include 'high reliability' nanocomposite solders and now even 'magnetic' solders.

The SPVC white paper prescribes general requirements for determining critical physical and mechanical properties of bulk lead-free solder alloys. The document describes material tests that generate portable data for: (1) direct comparison of different alloys; (2) aiding in alloy acceptability determination for various applications; (3) development of reliability models; and (4) other uses.

Included in the white paper is a new sample preparation process from Auburn University with small rectangular section glass tubes. Compared with the conventional dog-bone or casting specimens, the thickness of the Auburn uniaxial specimen is close to that of real CSP (0.25~0.5mm) and BGA (0.5mm) solder joints. It is claimed that this new specimen replicates the solder joint thermal history of typical electronic packages and also separates the specimen from the effects of other variables.

A free download of the white paper can be found on the reference link below.