Improved surface properties of AISI-304 by novel duplex cathodic cage plasma nitriding

In this work, novel duplex plasma nitriding is carried out on AISI-304 steel at fixed temperature of 400°C, using aluminum and austenite steel cages. The influence of (1-h) aluminum cage nitriding is investigated before (pre) and after (post) the (4-h) austenite steel cage nitriding. The treated samples are characterized using Vickers hardness tester, X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy. The results show that the post aluminum cage nitriding achieves excellent film quality, the highest surface hardness with aluminum nitride as a leading phase. This study shows that by using cathodic cages of various materials, cathodic cage plasma nitriding (CCPN) system can be effectively used for quick duplex treatment in a single setup. [Display omitted] •Duplex nitriding process is used for surface modification of AISI-304.•Austenite steel and aluminum cathodic cages are used for duplex nitriding.•The aluminum nitride is dominant phase in post-aluminum cage nitriding.•The hardness is significantly improved by post-aluminum cage nitriding.