Wear Characteristics Of Iron Research Articles

Fatigue wear characteristics of iron based sintered materials

Fatigue wear characteristics of iron based sintered materials

Effect of nitrided-layer microstructure control on wear behavior of AISI H13 hot work die steel

Gas nitriding has become a popular thermo-chemical surface treatment, which is being used to develop thermal/mechanical fatigue and wear characteristics of iron and steels. In this study, the gas nitriding of AISI H13 hot work die steel was carried out in flowing NH3 gas at 550°C for 5–15h. By adjusting the nitrogen potential ranging from 0.18 to 2.8, three types of nitrided surface layer consisting of ε-Fe2-3N and γ′-Fe4N phases, γ′-Fe4N single-phase, as well as the α-(Fe, N) phase had been prepared, respectively. The corresponding microstructure, hardness and thickness of the nitrided layer were systematically characterized. A contrastive analysis of influence of nitrided-layer microstructure control on wear behavior of AISI H13 hot work die steel was conducted. The nitrided surface layer consisting of ε-Fe2-3N and γ′-Fe4N phases showed excellent wear resistance under loads of 100N but poor wear properties at 300N. The wear mechanism was revealed based on the microstructure characteristics, surface hardness and toughness of each nitrided surface layer.

Effect of dissolved oxygen on the formation of iron fluoride, friction and wear in an iron/iron frictional system under perfluoropolyether fluid lubrication

The formation of iron fluoride, and the friction and wear characteristics of iron on an iron frictional system were studied in a vacuum and in various gas atmospheres of different oxygen content under branched perfluoropolyether (PFPE) fluid lubrication and dry sliding. The results showed that the friction and wear with PFPE lubrication is almost independent of the dissolved oxygen content, except for high wear in the vacuum caused by the formation of intensely corrosive iron fluoride at the fresh iron surface formed by wear. Dissolved oxygen reduces the harmful fluoride formation by forming an iron oxide film. The PFPE molecules react, however, at the oxide surface to form iron fluoride, the formation of which increases with an increase in the dissolved oxygen content because of the increased formation of the iron oxide.

Effects of Ion Implantation Conditions on the Tribology of Ferrous Surfaces

The effects of implanted nitrogen ion dose and target surface temperature during implantation on the wear characteristics of iron (ferrite) and 304 stainless steel (austenite) have been studied systematically. Wear test results obtained using an oscillating pin-on-disk tester show that high dose rate, high dose implantation into these materials when they are being held at an elevated temperature (near 400°C) induce dramatic improvements in their wear characteristics. Surface and near-surface analysis techniques are used to demonstrate that implanted ion dose and surface temperature can be controlled to produce a desired microstructural state and thickness of the nitrogen-implanted layer. The most wear resistant surfaces are produced when γ’-Fe4N is formed in the ferrite and a concentrated solid solution of nitrogen is produced in the austenite. Implanted layer thicknesses greater than ~ 1 μm (an order of magnitude beyond the ballistic implantation depth) are observed in the austenite.

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