The Effect of Time and Temperature of Nitridation-Oxidation Process on Properties and Corrosion Resistance of AISI 316L Steel

Yazdkhasti M., Hosseini S. A., Javadinejad H., Zare H., Rizi M., Abedi H.

SURFACE ENGINEERING AND APPLIED ELECTROCHEMISTRY, cilt.54, sa.5, ss.508-517, 2018 (ESCI, Scopus)

Özet

In this research, AISI 316L austenitic stainless steel has been subjected to plasma nitriding and oxidation- nitridation heat treatment at several temperatures for different times. Plasma nitriding of the samples was performed in N-2/H-2 = 1/3 atmosphere at temperatures of 425, 450, and 475 degrees C for 5 h. To study the effects of the combined nitridation-oxidation process on mechanical and physical properties, the samples have been exposed in O-2/H-2 = 1/5 oxidating atmosphere at 425, 450, and 500 degrees C for 15, 30, and 60 min, respectively. The mechanical and physical properties of the samples were studied after nitridation-oxidation heat treatment. The microstructural properties were examined by optical microscopy and scanning electron microscopy; the phases were analyzed by X-ray diffraction. The wear behavior of the oxidized-nitrided samples was studied using pin-on-disk tribotesting. The hardness and depth of the nitrided layer were measured by a Vickers hardness tester. The corrosion resistance of both untreated and treated samples was tested by the Tafel polarization and potentiodynamic polarization in 3.5% NaCl solution at ambient temperature. The results indicate that the combined nitridation-oxidation heat treatment improves both the pitting corrosion and wear resistances of AISI 316L steel and further increases its hardness.