Corrosion Behaviour of 17-4 PH Stainless Steels Produced by Adding Different Amounts of Alloying Element and Aged at Different Times

Abstract

In this study the corrosion behaviour of 17-4 PH (precipitation hardening) stainless steel alloys, produced by adding Ta different amounts with the method of powder metallurgy, and aged at different times was investigated. Four different amounts tantalum (0.15, 0.30, 0.45 and 0.60% weight) was added to the alloy. The prepared powders were produced green compacts at ∅10 × 6 mm dimensions (800 MPa) after mixing with turbule for 2 hours. Green compacts produced were sintered for 1 h at 1300°C under a vacuum of 10^–6 mbar. The sintered samples were aged 1, 4 and 8 hours at 480°C after being in solution at 1050°C. Polarization measurements were performed in a corrosion cell, using three different electrode technique. In the corrosion tests, 0.1 M H₂SO₄ was used as the electrolyte medium. As a result of the studies, the alloy the hardness and densities were increased with increasing Ta amount. Similarly, the hardness and densities of produced samples were with increasing aging time. The corrosion tests revealed that increasing the amount of Ta added to the alloy increased the alloy’s resistance to corrosion. The alloy’s corrosion resistance decreased as aging time increased. The active corrosion mechanism was seen to be pitting corrosion in all alloys.