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Studies have been made of ageing effects, both at room temperature and at 125°C, on the microstructure of 60:40 tin‐lead solders. A comparison was made of the effect of ageing on slow and rapidly cooled matrices. Precipitation of tin within lead dendrites was observed to occur very rapidly after solidification of the alloy. Subsequently the precipitates coarsened markedly over a period of a few weeks. The matrix of the alloy also coarsened at room temperature over this period. At elevated temperatures a similar sequence of events occurred, but substantially faster. The microstructural origins of the known loss in mechanical strength of solders with ageing are discussed.

A model SMD test‐piece has been developed which permits mechanical stressing of a solder joint in a similar mode to that occurring in the process of thermal fatigue. The failure mechanisms in the 60Sn40Pb alloy studied have been in agreement with those frequently observed in thermal fatigue. Further, the fatigue life of model joints was found to increase with increasing solder volume whilst, upon ageing at room temperature, fatigue resistance decreased. These effects were attributed to microstructural changes occurring within the solder.

This February meeting began in somewhat dramatic fashion—not with the actor's usual injunction to ’break a leg‘ but with the Chairman's announcement that Stuart Briggs, the fourth of the seven presenters, had broken an ankle. It subsequently transpired that he had evidently ’only‘ torn the ligaments, but his presence at the seminar was sorely missed and I know all will wish him a speedy recovery.

The meeting, held on 17 May 1990, was opened promptly by the Chairman Andrew Nicholson, who welcomed everyone to the Seminar and introduced Tony Harman, who gave a very good review of the present situation of cleaning electronics assemblies before turning to future developments. In his paper ‘An Assessment of CFC Replacements—Proposed UK Collaborative Programme’, Tony developed the ideas which had led the UK Government to support this work. He did, however, point out that the funding was only now becoming available and this had delayed the start of the programme. Nevertheless, the itinerary of the cleaning trials had been decided and the practical work would commence shortly. In general terms, the programme will cost £¾m and will use between 600 and 700 test boards. As this programme is funded by Central Government, the results will be widely disseminated, especially to Small and Medium Enterprises.

There is continuous pressure in the electronics industry towards miniaturisation. This has led to the development of fine pitch soldered devices, and this paper considers the concept of solder creams which use a restrictive flux system as suitable for this work, rather than those that employ finer powder. It is shown that the latter type of solder cream must use metal powders with a higher oxide content which will require the cream to contain a more active flux.

Joints made to the Surface Mount configuration for a chip capacitor using either 60Sn40Pb or 62Sn36Pb2Ag solders were found to weaken substantially during storage at room temperature. This loss in joint strength is attributed to microstructural changes in the solder, particularly precipitation of the β phase and recrystallisation of the matrix, i.e., the two solid solutions (α + β), and the subsequent coarsening of the microstructure.

Drive east from Frankfurt, upstream along the valley of the River Main, and in 25 kilometres or so you will reach Hanau, where once the brothers Grimm lived and collected the folklore which we now know as the famous Tales. Here too, in 1856, Wilhelm Carl Heraeus, a chemist and pharmacist, proprietor of the pharmacy which had carried the family name for many generations, succeeded in producing temperatures approaching 2000°C from an oxy‐hydrogen flame, temperatures sufficiently high to achieve the melting point of platinum and to allow him to melt substantial quantities of this metal for the first time. Hanau was then a centre for the jewellery manufacturing industry (and remains so today) so the smelting of platinum and other precious metals had an immediate commercial relevance.

Bryan Pledger, Chairman of the IMF Printed Circuit Group, chaired this meeting, held in London on 26 September, and introduced the panel of speakers, well‐known nationally and internationally, and specialists in the field of surface mounting.

Although the subject discussed at this meeting is one in which I have a personal and commercial interest, I will try to report the meeting in an unbiased manner. I must, however, point out that I asked only one question at the meeting and that was when one of the speakers compared solder cream to sand. I believe this type of comment shows a complete misunderstanding of the sophisticated material that is today's solder cream and especially of solder cream designed for ‘fine‐pitch soldering’.

The annual Autumn Conference of the British Association for Brazing and Soldering offers a forum for discussions between scientists and engineers involved with two technologies which, because of their obvious similarities, would be expected to be of mutual benefit and learning. In reality both the science and the practice of brazing and soldering are quite different. I suspect, with some regret, the BABS Management Committee decided that for the first time this division be formally recognised by offering soldering as the subject of the first day and brazing and diffusion bonding the subjects of the second. This report covers the soldering day only, during which seven papers were presented: