Abstract
Bright tin-lead alloys containing 100-50% of tin were electrodeposited from a phenolsulfonate bath containing a condensation product of acetaldehyde with o-toluidine, a non-ionic surface active agent, and acetaldehyde. An alloy deposited from the bath at 2-5Amp/dm2 had a smooth surface and a good luster. The composition or lead content of the deposited alloy was nearly equal to that of the bath over a wide range of current densities from 0.25 to 10Amp/dm2. The additives showed brightening effect on a single tin deposit, but not on a single lead deposit; and well-defined orientation of tin crystals was recognized in the X-ray diffraction pattern of the panels deposited from the bath containing brighteners. Therefore, the brighteners seem to interact mainly with tin during electrodeposition. Anodic dissolution of alloys was smooth, and no passivation occurred in the bath. The throwing power of the bath was in the same degree as that of a fluoroborate bath.
