Tribological Properties of Tin and Bronze Coatings Electrodeposited from Acid Baths

L.N. BENGOA; N. ZABALA; W.R. TUCKART; W.A. EGLI

Buenos Aires

Workshop; 2º International Workshop of Tribology-TRIBaires 2013; 2013

Asociación Argentina de Tribología

The aim of this work is to develop an acidic non-cyanide electrolyte for the electrodeposition of high quality bronze coatings and evaluate their tribological behavior. To this end Cu+2 additions were done to PSA and MSA based tin-plating electrolytes. Tin deposits were also obtained from both baths. For the PSA electrolyte industrial additives were used. In the case of the MSA solution a study of organic additives was necessary previously to obtain a homogeneous deposit. Cyclic voltammetry was used to study different organic additives added to the solutions. The deposits obtained were characterized with scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction The friction coefficient and wear resistance of tin, copper and copper-tin alloy coatings was studied through dry sliding wear tests carried out with a homemade ball on ring system. A novel cyanide-free bath for the electrodeposition of bronze was developed. The deposit obtained has a mono-phase (α-phase) matrix (77%Cu-23%Sn). Tin coatings were electrodeposited from different electrolytes and these coatings presented differences in morphology and tribological properties. The tin coating electrodeposited from a PSA-bath has a lower coefficient of friction and higher wear resistence than tin deposit obtained from a MSA electrolyte and bronze coating.