Eletrodeposição da liga Co-W-P resistente a corrosão.

Abstract

The study for obtaining Co-W-P alloys have been developed in recent years and is considered one of the most effective methods for improving the chemical and physical properties of metal surfaces. Electroplating is an alternative method for producing such coatings. The Co-W-P alloy has owned eletrocatílicas for hydrogen production, magnetic properties and has low thermal expansion. This work aims at obtaining and characterization of Co-W-P alloy using electrochemical techniques. The alloys were characterized for their deposition efficiencies, corrosion resistance, and chemical composition. As a tool for optimizing the electrodeposition process was used for response surface methodology. The plating bath used in the electrochemical Co-WP was composed of the following chemical reagents: 46.0160 g/l sodium tartrate cobalt sulfate 8.4330 g/l sodium tungstate 3.2986 g/l Ammonium Sulfate 2.6428 g/l sodium hypophosphite 2.1198 g/l. The pH of the bath was maintained constant with a value adjusted to 9.0 and adding ammonium hydroxide or sulfuric acid. From the results it can be concluded that the optimum values found for the current density, and bath temperature Co-W-P alloy are 30 mA/cm2 and 80 ° C respectively. To this was achieved a higher efficiency of filing and polarization resistance. Regarding the composition of the alloy the best experiment had the following composition: 86 wt% Co, 12 wt% W and 2 wt% of P.