抄録
The baths containing a mixture of silver cyanide and stannous pyrophosphate were prepared for studying improvement in anti-tarnish property of Ag alloy deposits. The bath compositions and electroplating conditions for obtaining the deposits having about 10% of tin content and the properties of the deposits were examined.
The results obtained were as follows:
(1) A bright Ag alloy deposit (80-95% Ag) was obtained with stirring from a bath containing free K4P2O7 75-150g/l, free KCN 15-25g/l, Sn2+7-15g/l, Ag+8-16g/l and H2O2 (30%) 1-3ml/l by electrolysis under cathodic current density of 0.3-1.0Amp./dm2.
(2) The bath became turbid and precipitate was formed with the lapse of time. However the process could be retarded to some extent by addition of a small amount of H2O2.
(3) As compared with single Ag deposit, Ag-Sn alloy deposits had higher hardness and lower anti-tarnish property.
