Sérgio Deitos Bittencourt

Analysis of different current density conditions in the electrodialysis of zinc electroplating process solution

ABSTRACT The use of currents below and above the limiting one for the treatment by electrodialysis of a solution prepared as a surrogate of a rinse water of the acid zinc electroplating processes was studied. The ionic transport behavior was evaluated by chronopotentiometry. The limiting current values were obtained through current–voltage curves. The trials performed with different current densities showed that the electrodialysis removed at least 98% of the contaminants without insoluble species precipitation on membrane surfaces. The water reuse is possible after electrodialysis treatment with current densities above the limiting one and considering a demineralization rate of 60%.

Influence of Milling Time During the Mechanical Alloying Process on the Properties of Fe-3Si-0.75P Alloy

In this study the soft magnetic alloy Fe-3Si-0.75P (wt%) was obtained by mechanical alloying through powder metallurgy. The processing included the formulation of metallic powder, wet milling for 1 h, 3 h, 6h and 9 h, in an attritor mill using alcohol P.A. as a lubricant. Cold compaction was then performed in a floating die under 600 MPa pressure and, finally the ring-shaped test specimens were sintered at 1150 °C for 1h. The electrical, physical and magnetic properties were then analyzed using the following assays: Laser granulometry, density, metallography, hysteresis curve and AC permeability, resistivity and XRD. The results showed a strong influence of milling time on magnetic properties of the alloy. There was a decrease in grain size with the milling time, which is likely the cause of increased in magnetic properties.