During the run-up to the change to lead-free solders by July 2006, a number of end users have expressed concerns about the reliability of soldered joints formed by mixtures of tin/lead (SnPb) and lead-free materials. These will arise when lead-free components are soldered using SnPb alloys, something already happening in many production lines, and later when SnPb components are soldered with lead-free alloys. The latter issue may be a significant problem for companies that have had to invest in lifetime purchase of components. Several workers have already published information that suggests that small levels of lead contamination in lead-free joints can significantly reduce joint performance.

Many of those concerned end-users approached National Physical Laboratory (NPL, Teddington, UK) to assist with clarification of any reliability issues during the transition period. A consortium of 16 contributing companies was formed with a work program. The work will cover reliability assessment of lead-free joints to SnPb components; reliability assessment of SnPb joints to lead-free components; evaluation of hot-peel strength of lead-contaminated lead-free joints; and applicability of lead indicator kits for paints for recognition of lead-containing components

The work, lead by Martin Wickham, is underway and results are expected in the next 12 months.

Participating partners include:

Aeroflex International Ltd.
AMS Space UK
BAE SYSTEMS (Operations) Ltd.
Celestica Ltd.
Department of Trade & Industry
Dolby Laboratories Inc.
Eurotherm Ltd.
Goodrich Engine Control Systems
Hansatech Group
National Physical Laboratory
Robert Bosch GmbH
Rolls Royce Naval Marine
TRW Automotive
Thales Missile Electronics Ltd.

For more information please contact Dr. Chris Hunt: +44(0)20 8943 7027; email: chris.hunt@npl.co.uk.

www.npl.co.uk

Copyright 2004, UP Media Groups. All rights reserved.

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