Jianrong Sun

Preparation and Tribological Behavior of Self-Lubrication Composites Ni-W-Cr-Fe-Cu-MoS2-Graphite at Elevated Temperature

The composites of Ni-W-Cr-Fe-Cu-MoS2-Graphite with nano-MoS2 were prepared by powder metallurgy. Its tribological properties were investigated using the UTM-2 Nano+Micro Tribometer from room temperature to 600°C. The effects of amount of MoS2 and Ni-W-Cr prealloy powder, load, and temperature on the tribological properties were investigated and discussed. The results indicated that the addition of 43~45wt.% Ni-W-Cr prealloy powder had a strengthening effect on the hardness, anti-press and tensile strength. The tensile strength of the composite decreases with the addition of Nano-MoS2 and graphite, and the friction coefficient decrease with increase of the additives over the wide temperature range of 25°C∼600°C. The friction coefficients and wear rates of the composites reach the optimization value at 2.5wt.% MoS2,While its wear rates increase with the increasing temperature and load.

Tribological Properties of Ni-Cr-W Matrix High Temperature Self-Lubrication Composites Sintered by Hot Isostatic Pressing

The high temperature self-lubrication Ni-Cr-W matrix composites were prepared by powder metallurgy and sintered by hot isostatic pressing (HIP). Atomized Ni-Cr-W powder was mixed with friction components of MoS2 and Graphite. The mixed powders were cold pressed 450MPa and sintered at 1100°C~1200°C in the presence of argon atmosphere for 1 hour under 180MPa hot isostatic pressing with respect to their application in slide bearing bushing. The tribological properties are investigated on UMT-2 tester in ball-on-disc against alloy steel ball. The results showed that the appropriate addition of MoS2 show excellent antifriction and wear resistance. And the friction coefficients and wear rates decrease over the wide temperature range of 25°C~600°C compared that of the composites by pressureless sintered method. The results indicated that HIP technology had an obviously strengthening effect on the density, and anti-press strength.