title: Phase formation in selected surface-roughened plasma-nitrided 304 austenite stainless steel.
abstract: Direct current (DC) glow discharge plasma nitriding was carried out on three selected surface-roughened AISI 304 stainless steel samples at 833 K under 4 mbar pressures for 24 h in the presence of N2:H2gas mixtures of 50 : 50 ratios. After plasma nitriding, the phase formation, case depth, surface roughness, and microhardness of a plasma-nitrided layer were evaluated by glancing angle x-ray diffractogram, optical microscope, stylus profilometer, and Vickers microhardness tester techniques. The case depth, surface hardness, and phase formation variations were observed with a variation in initial surface roughness. The diffraction patterns of the plasma-nitrided samples showed the modified intensities of the α and γ phases along with those of the CrN, Fe4N, and Fe3N phases. Hardness and case depth variations were observed with a variation in surface roughness. A maximum hardness of 1058 Hv and a case depth of 95 μm were achieved in least surface-roughened samples.
authors.affiliation: Materials Science Centre, Indian Institute of Technology, Kharagpur 721302, West Bengal, India.
authors.forename: Gajendra Prasad
authors.initials: GP
authors.lastname: Singh
authors.affiliation: FCIPT, Institute for Plasma Research, B15 - 17/ P, GIDC, Sector 25, Gandhinagar 382044, Gujarat, India.
authors.forename: Alphonsa
authors.initials: A
authors.lastname: Joseph
authors.affiliation: FCIPT, Institute for Plasma Research, B15 - 17/ P, GIDC, Sector 25, Gandhinagar 382044, Gujarat, India.
authors.forename: Prakash Manohar
authors.initials: PM
authors.lastname: Raole
authors.affiliation: Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215, Jharkhand, India.
authors.forename: Prema Kanta
authors.initials: PK
authors.lastname: Barhai
authors.affiliation: FCIPT, Institute for Plasma Research, B15 - 17/ P, GIDC, Sector 25, Gandhinagar 382044, Gujarat, India.
authors.forename: Subroto
authors.initials: S
authors.lastname: Mukherjee
keywords: AISI 304 steel; hardness; phase analysis; plasma nitriding