Per: Lucas de Mendonça Neuba (Instituto militar de engenharia), Alexsandro de oliveira (UniFOA), Sergio neves monteiro (Instituto militar de engenharia), Alexandre alvarenga palmeira (Universidade estadual do rio de janeiro)
Abstract:
The constant search for the improvement of projects and products is of extreme importance to guarantee the product availability and reliability of them. The comparative study done in the present work relates the characteristics of sealing rings using CuAl bronze with tin surface (Sn) as a material with CuAl brass rings with superficial Pb, both applied in a positive displacement or volumetric displacement pump. 6 samples of SAE-68D aluminum bronze, with dimensions of 2.5 x 2.5 x 50 cm, were used to obtain a superficial layer of superficial Pb. 3 SAE-68D aluminum bronze rings, having internal diameter dimensions 35.4mm and external diameter 46.9mm, were used as samples. Through a thermochemical treatment process, after with periods of treatment different from 3, 4 and 5 hours. For these periods a diffusion of lead occurred on the surface of the rings. Analyzes made from captured images of each brass ring with shallow Sn by a scanning electron microscope and 2 samples for the Pb were sectioned in order to prove the migration of the lead. Pb showed an easiness diffusion on the base metal surface, however, it does not diffuse in the inner layers of the base metal without altering the properties.