Wear Volume Loss Rate Research Articles

Micro-abrasive wear study of a low-temperature plasma nitrided Inconel 625 superalloy

ABSTRACT In this study, the microabrasive wear of a plasma nitrided Inconel 625 superalloy was studied. Nitrogen supersaturation in the expanded FCC layer promoted hardening due to the higher compressive residual stresses. The results showed the formation of a nitrided layer consisting of nitrogen expanded FCC phase (γN) and CrN nitride, respectively. Friction coefficient, mechanical failure mode and critical loads for damaging the nitrided case, using the linear scratch test, were carried out at a linearly increased normal force. The scratch test results showed that the nitrided layer strongly decreased the apparent friction coefficient in comparison with the non-nitrided alloy. Tensile cracking was the prevalent mechanical failure mode of the nitrided layer. Microabrasion results showed that the nitriding layer improving the wear resistance. For the nitrided samples, wear coefficients were determined for the nitrided layer and the substrate, indicating a change in the wear volume loss rate with the test distance.

Investigation of two-body wear resistance of composite materials for biomaterial application in oral environment: the influence of antagonist material

ABSTRACTThe purpose of this study was to investigate the effect of antagonist material on two-body wear resistance of modern composite dental materials. Kalore, 3M ESPE P60, Grandio and Heliomolar dental composite materials were exposed to in vitro chewing simulation tests using different antagonist materials. The mean volume loss of the worn surfaces was measured with a non-contact 3D profilometer after chewing test procedures. As a result of the interactions between antagonist material and mean volume loss of composite materials were found to be significant. Among the tested materials highest two-body wear volume loss rate was obtained when P60 composite material was used as an antagonist. To reduce volume loss of contact-wear mechanism that the use of the harder structure of antagonist composite material should be avoided or if it is a hard fill the particles be reduced to nano size.

Assessment of tribological properties of plasma nitrided 410S ferritic-martensitic stainless steels

Low Temperature Plasma Nitriding (LTPN) is a surface treatment that promotes surface hardening without harming the corrosion resistance of martensitic stainless steels. LTPN and conventional plasma nitriding (CPN) treatments were carried out to compare the influence of the obtained nitrided layers on the abrasive wear resistance of AISI 410S ferritic-martensitic stainless steel. The samples were plasma nitrided for 20 h in a gas mixture of 75% N2: 25% H2, at 250 Pa. LTPN was carried out at 400 °C, obtaining a 50 µm thick expanded martensite layer. CPN done at 530 °C, resulted in a 170 µm nitrided layer, with an outermost compound layer 15 µm in thick. Nanoindentation tests to assess the mechanical properties and the energy dissipation coefficient were carried out. Scratch and micro-abrasion tests were conducted to evaluate the friction coefficients, failure modes, critical loads and wear resistance. Tensile cracking was the prevalent mechanical failure mode of the nitrided layers. Micro-abrasion results showed that LTPN and CPN samples exhibited similar wear volume losses. A change in the wear volume loss rate with sliding distance was observed for the nitrided samples. A change from grooving to rolling abrasion explains the change in the wear rate.

Microstructure and Wear Resistance of Laser Cladded Ni-based Coatings with Nanometer La 2 O 3 Addition

Ni-based coatings with nano-sized feedstock rare earth element (RE, La2O3) addition were produced by laser cladding. Bed of high energy ball milling mixed Ni60A and La2O3 powders were pre-placed onto the substrate 30CrMnSiNi2A before laser cladding. Results show that La segregates in inter dendrite and thus secondary dendrites growth and ripening are limited. The microstructure is refined. Top surface of the cladded coatings displays better refined microstructure which is caused by high La concentration, and this phenomenon is verified in EPMA results. The cracks and pores cannot be found in cladded coatings in which microstructure refinement and purifying effect caused by RE is clearly reflected in SEM microstructure, hardness and especially the wear resistance test results. The COF (coefficient of friction) of the coatings is apparently lower than that of substrate steel; the wear volume loss rate and the microhardness of coatings are less than 1/10 and about 4 times higher than that of substrate metal, respectively. This research forms the basement of metal surface anti-wear layer on the work surface of high speed heavy duty gear set in helicopter transform system.