Tin on copper

Tin on Copper and Copper Alloy (including Brass) Components... 

Ereer, J., and Morris, J., Microstructure and Creep of Eutectic Indium-Tin on Copper and Nickel Substrates, Journal of Electronic Materials, Vol. 21, No. 6,1992, pp.647-652. 

Hot air solder leveling (HASL) or reflowed tin on copper bond pads possess a thin intermetallic layer between the applied surface finish and the pads. During surface-mount technology (SMT) reflow, the addition of molten solder on top of this preexisting intermetallic layer will further its growth. Therefore, the TAL should be limited to minimize IMC but sufficient for good solder wetting. 

AF+ which is reduced to the elemental state. The distinct feature of the immersion plating process is therefore its reliance on a spontaneous reaction. Thus, the feasibility of the process is dictated by the relative nobility of the metals involved as film and substrate material. The relative nobihty is determined by the position in the electrochemical series yet can be altered and even reversed with respect to the dictate of the latter by recourse to complex chemistry. An example of reversed nobility is encountered in the immersion tin process used to deposit a thin layer of tin on copper substrate. 

The metal is slowly oxidised by air at its boiling point, to give red mercury(II) oxide it is attacked by the halogens (which cannoi therefore be collected over mercury) and by nitric acid. (The reactivity of mercury towards acids is further considered on pp. 436, 438.) It forms amalgams—liquid or solid—with many other metals these find uses as reducing agents (for example with sodium, zinc) and as dental fillings (for example with silver, tin or copper). 

Tin babbitts are based on the tin—antimony—copper system and commonly contain about 3—8% copper and 5—8% antimony. Within a soft, sohd-solution matrix of antimony in tin are dispersed small hard particles of the intermetaUic copper—tin, Cu Sn [12019-69-1] (13). 

Contrary to proponents assumptions, natural dyes are not necessarily environmentally friendly. First, large amounts of plant waste would be produced because of the low dye content in plants, eg, 170 million t of waste to color the cotton volume. Also, in order to dye fabric with natural dyes, "mordants," which are usually based on heavy metals, have to be used. For example, madder is appHed with tin (Sn) or aluminum (Al). Weld is appHed with tin salts. Salts based on copper and iron can also be used. 

Nickel on nickel Gold on gold Platinum on platinum Copper on copper Indium on indium Lead on lead Aluminium on aluminium Silver on silver Iron on iron Tin on tin Steel on tin alloy Steel on steel Steel on Pb alloy Steel on Al. bronze Steel on cast iron Steel on brass Steel on bronze Steel on Pb. brass... 

With industry proving to be so conservative about binary alloys it is hardly surprising that ternary alloys receive little attention. Nevertheless, two ternary alloys at least have become commercially available iron-chromium-nickel (so-called stainless steel) for both functional and domestic markets and an electronic connector and solderable alloy based on copper-zinc-tin. 

Alloy formation is faster on copper than on steel and tends to be more irregular. With coating thicknesses of 1 /im or less, the thickness of the alloy layer may amount to half that of the complete coating. It consists of a thin layer of CujSn adjacent to the copper and a thicker layer of Cu Snj adjacent to the tin. 

Table 13.13 Thickness suggested for electrodeposited tin coatings on copper and copper alloys with at least 50% copper...

Fairly stable in steel containers at 65°C. Stability improves with increasing purity. Attacks tin, magnesium, cadmium plated steel, some aluminums slight attack on copper, brass, lead practically no attack on 1,020 steel, Inconel and K-monel. 

In spite of higher capacity of tin electrode on tungsten current collector in comparison with tin electrode on copper current collector, specific capacities for unit of electrode mass have the reverse correlation (Table 3). 

If a piece of copper metal was placed in a solution of SrfNOj aq) there would be no reaction, since copper is lower than tin on the activity series. This table allows us to also predict that if sodium metal is placed in water, it will displace hydrogen, forming hydrogen gas ... 

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