Study of the characterization and corrosion in NaCl medium of duplex stainless steel obtained by powder metallurgy

The industrial sectors of oil extraction and refinement and oil and gas transportation has driven the appearance of alloys increasingly resistant to corrosion, for acting in environments with high content of chloride ions and with temperature variations, such as the marine environment. A much applied alloy in the facilities of these sectors is stainless steel of the duplex family, for presenting good mechanical behavior and resistance to corrosion. Recently, powder metallurgy has been used to obtain these alloys from the powder of their constituents, using sintering. The technique has shown a better cost-effectiveness compared to conventional casting techniques. However, little is known about the behavior of these sintered alloys as corrosion resistance in NaCl medium. In this way, this work had the objective to characterize the sintered duplex stainless steel and to study its corrosion resistance behavior in 1 mol dm^-3 NaCl medium at three temperatures, 25 °C, 35 °C and 45 °C. For this, non-solubilized and solubilized samples at the temperature of 1100 °C for 30 minutes and 60 minutes were used. Optical Microscopy, Scanning Electron Microscopy, X-ray Dispersive Energy and Electrochemical Techniques ware used for the investigation. The results revealed that the samples solubilized for 30 minutes presented better anticorrosive performance. (author)