Equipment mild steel

Anodes must be filmed. (An oxide film is deposited on the anode by plating it at a high current density.) Unfilmed anodes cause formation of stannite (Cu2FeSnS4), which inhibits plating.

Temperature. Temperatures in the high end of the range increase the tin content and cause the cyanide to break down. Low temperatures decrease cathode efficiency and lower the percentage of tin.

Current densities at the low end of the range result in tin-rich deposits.

Electrolyte Concentrations. The proportions of zinc and tin in the deposit vary with the amounts in the solution. Higher concentrations of zinc in solution result in higher levels in the deposit, and likewise with tin. Higher levels of free potassium hydroxide increase the percentage of zinc in the deposit. Small changes in free cyanide content have little effect, because the solution contains more cyanide than is necessary. Excessively low levels of cyanide decrease tin content (Ref 9).

Tin-Nickel Plating. The intermetallic compound 65Sn-35Ni can be plated from several commercial electrolyte solutions. The finish has high lubricity and a bright, chromelike appearance with excellent corrosion resistance, especially in seawater environments. It is used more often for general industrial applications than for electronic components, because it is more difficult to solder than other tin-alloy coatings. The solution composition is:

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