Copper-tin electrodeposits are used in protective and decorative finishing of metals. For the commercial electroplating of copper-tin alloys, the stannate-cyanide bath is broadly employed but it is not desirable to use the cyanide baths in respect of pollution controll. The reference to the use of the pyrophosphate bath containing no cyanides is poor except for Rama Char's works. In the present work, studies on the electrodeposition of copper-tin alloys from the pyrophosphate bath containing no cyanides were undertaken with a view to establishing: 1) the effect of concentration of sodium pyrophosphate and ammonium oxalate on the cathodic polarization 2) the effect of plating variables on the composition, current efficiency and the structure of deposits. 3) the relations between tin content in deposits and lattice constant, macro stress and microstrains of electrodeposited α-Cu alloys.
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