Effect of N{sub 2} + H{sub 2} gas mixtures in plasma nitriding on tribological properties of duplex surface treated steels

Journal Article · Mon Dec 15 04:00:00 EST 2008 · Materials Characterization

DOI:https://doi.org/10.1016/j.matchar.2008.04.010· OSTI ID:21192579

Taktak, Sukru ^[1]; Gunes, Ibrahim; Ulker, Sukru; Yalcin, Yilmaz ^[1]

---

1. Afyon Kocatepe University, Technical Education Faculty, Department of Metal Education, Afyonkarahisar (Turkey)

Thermo-reactive diffusion chromizing followed by pulsed plasma nitriding were carried out on AISI 52100 and 8620 bearing steels. The chromized samples were pulse-plasma nitrided for 5 h at 500 deg. C in various N{sub 2}-H{sub 2} gas mixtures. The coated steels were characterized using scanning electron microscopy, X-ray diffraction and microhardness testing. The unlubricated wear behaviors of only chromized and duplex treated steels were investigated in ball-on-disc system tests at room temperature. X-ray diffraction patterns of the duplex treated samples containing H{sub 2} indicated the formation of dominant CrN and Cr{sub 2}N nitrides as well as the formation of Cr{sub 3}C{sub 2} and Cr{sub 7}C{sub 3} carbides. Gas mixtures in the plasma nitriding, which was performed after chromizing, have a significant influence on the wear rate of the duplex treated steels. The wear and friction tests showed that the lowest friction coefficient and wear rates were observed for the samples duplex treated in a 50%N{sub 2} +50%H{sub 2} plasma. Conversely, the lowest wear resistance was observed on the samples duplex treated in a gas mixture of 75%N{sub 2} + 25%H{sub 2}, probably due to formation of a hard and brittle layer.

• OSTI ID: 21192579
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 12 Vol. 59; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM CARBIDES
CHROMIUM NITRIDES
DIFFUSION COATING
FRICTION
FRICTION FACTOR
HYDROGEN
LAYERS
MICROHARDNESS
PLASMA
SCANNING ELECTRON MICROSCOPY
STEELS
SURFACE TREATMENTS
SURFACES
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
WEAR
WEAR RESISTANCE
X-RAY DIFFRACTION