The iron–tin alloy layer on commercial tinplate was shown to be severely disrupted as a result of drawing in a laboratory press. This resulted in increased alloy tin couple (ATC) values for the material which could be reduced by a heat treatment after drawing. Fortifying the alloy layer by heat treatment before drawing did not have the same effect. It is suggested that the low ATC values produced by the heat treatment were a result of changes in the electrode properties of the alloy layer which did not produce enhanced performance from tinplate subjected to an accelerated simulated can corrosion test. Additionally, the samples used in this corrosion test showed uneven detinning after drawing which persisted after the heat treatment.

AbstractThe inhibition of iron corrosion from damaged lacquered tinplate in oxygen free pH 4 citrate buffer solution by the addition of stannous tin has been demonstrated using an accelerated simulated can corrosion test. The inhibition was total for tinplate of nominal coating mass 2·8 g m−2 for additions of 5–15 ppm of stannous ion, but was only partial for tinplate of nominal coating masses 1·4, 1·0, and 0·5 g m− up to a 60 ppm addition. The extent of undermining of the lacquer from around a standard scratch was shown to be dependent on the tin coating mass remaining on the tinplate, rather than the presence of stannous ions in solution.

SummaryThe contact resistance of standard gold, thin gold, electroplated tin, electroplated tin-lead, hot dipped tin, hot dipped tin-lead and electroplated duplex tin on tin-nickel was measured unaged, after steam ageing and after salt spray testing. The results are compared and assessed for use as coatings on separable electrical connectors.

Introduction The International Tin Research Institute has approximately 80 staff working at the Headquarters and Laboratories of the organisation near London. Half of these are directly engaged in research into existing and potential uses for tin and the work is organised into two main Divisions. One of these, the Metallurgy and Tinplate Division contains a section devoted to tinplate research and additional support is drawn from the Analytical Chemistry and Metallography Sections as it is required.

AbstractThe efficacy of a simulated can test to accelerate some of the corrosion reactions occurring in canned foods has been demonstrated. This test has been used to deduce the distribution of results for the migration of lead, tin and ironfrom three-piece cans with aconventional soldered side-seam. The study also reports the effect of a number of can design and usage parameters on corrosion. These include the effect of oxygen in the headspace gas, and of processing and storing on the corrosion of 2%Sn/98%Pb solder in combination with lacquered and unlacquered tinplate. A second paper describes the further use of this procedure to study the relevance of otherfactors to side-seam corrosion.

SummaryThe effect of coating alloy composition on the corrosion resistance and porosity of laboratory produced terneplate is assessed. The results indicate that an increase in the tin content of a coating alloy is beneficial to coating quality whereas substitution of antimony for tin is detrimental to coating performance under test. The metallurgy of the bond between the steel substrate and alloy coating is considered, and the likely causes of pores occurring through the coating, which are the sites of subsequent corrosion, are reported.

Tin and solder coatings interact with substrates commonly used in the electronics industry to produce layers of intermetallic compounds at temperatures above and below the melting point of the coatings. Observations on the rates of compound growth at room temperature for durations of up to 12 years are reported and related to the published results for shorter times at higher temperatures. Recent results concerning the effect of intermatallic compound growth on the solderability of coatings and on the strength of soldered joints are presented. In both cases it is apparent that retarding the rate of compound growth could be useful and the use of barrier layers for this purpose is considered.

SummaryThe solid state diffusion of copper and tin to produce intermetallic compounds at the interface between a coating of tin on copper or brass may be severely restricted by the use of a barrier layer of electroplated iron. Ultimately the barrier fails by rupturing due to the growth of copper/tin intermetallic compounds at pores in the iron layer.

AbstractAn accelerated simulated can corrosion test has been used to study a number of factors relevant to the corrosion of the soldered seam used in the fabrication of three-piece tinplate containers. Using oxygen headspace concentrations in excess of those normally found in cans, the effects of solder composition and electrolyte composition on the corrosion of 2%Sn/98%Pb solder in the presence of lacquered and unlacquered tinplate have been studied. It has been shown that changing the composition of the solder can affect the amount of lead dissolved during the tests, while the existence of electrical contact between the solder and tinplate has been shown to be important in some cases. Electrochemical measurements were made in order to rationalise the observed effects.

SummaryThe autocatalytic deposition of tin onto steel, nickel, copper, polypropylene and ABS from a solution containing tin (II) and titanium (III) salts and complexing agents has been demonstrated. Coating continues at a rate of 4 g m−2 h−1 up to at least 10/μm. Preliminary experiments designed to demonstrate the reaction mechanisms involved have failed to identify the species in solution but it is believed that the reducing agent is a Ti3+ ion which has a tin-containing ligand in its coordination sphere.

AbstractInternal lacquering of food cans, by restricting dissolution of tin, may lead to undesired changes in some packed products and to increased dissolution of iron and of any exposed solder. It has been shown that the introduction of tin particles into the lacquer may overcome these disadvantages with an effectiveness that depends on the size of the particles in relation to film thickness. This dependence is explained in terms of the area of tin exposed when different size ranges of tin powder are present in the lacquer film.