Zhuhui Qiao

Tribological Behavior of Tin-Based Babbitt Alloy Lubricated by Seawater

ABSTRACT In this article, the tribological behaviors of tin-based Babbitt alloy ZChSnSb 8–8 sliding against AISI 302 stainless steel lubricated by seawater were investigated. The results indicated that the friction coefficient decreases with increasing load and sliding speed, and the wear rate increases slightly with load but decreases with sliding speed. The low friction coefficient and wear rate are attributed to the unique “concrete structure” and seawater. As a lubrication medium, seawater has lubricating, cooling, and corrosive effects on the sliding couple.

Effect of Counterface on the Tribological Behavior of Ti3AlC2 at Ambient

In this paper, we investigated the effect of counterface of AISI 52100 steel and ceramics of SiC, Al2O3, and Si3N4 on the tribological behavior of Ti3AlC2 at ambient. The results showed that the tribological properties of Ti3AlC2 are strongly dependent on the counterfaces. Under present test conditions, the tribocouple of Ti3AlC2/SiC exhibits lower coefficient of friction (CoF) 0.40, Ti3AlC2/AISI 52100 steel shows a rising CoF from 0.1 to 0.63, both Ti3AlC2/Si3N4 and Ti3AlC2/Al2O3 tribopartners exhibit higher CoF of 1.22 in average. The Ti3AlC2 exhibits the lowest wear rate sliding against AISI 52100 steel, the wear rate of Ti3AlC2 sliding against Al2O3, Si3N4, and SiC are higher and comparable. The morphologies of the worn surfaces of the Ti3AlC2 are observed by scanning electron microscopy, and the element states are analyzed by X-ray photoelectron spectroscopy. The wear mechanisms are discussed.

Tribological behavior of Fe3Al-60 wt.% Fe3AlC0.5 composite under air and vacuum conditions

Abstract The tribological behavior of Fe3Al composite with 60 wt.% Fe3AlC0.5 under air and vacuum was studied. The composite exhibited a lower wear rate but somewhat higher friction coefficient under air than vacuum. The wear rates increased and the friction coefficients decreased with increasing the applied load under both conditions. The sub-layer of the worn surface under vacuum suffered from severe plastic deformation. This was not the case under air due to protection by surface oxide films. The dominant wear mechanisms were plastic deformation and adhesion under vacuum and oxidative wear and slight delamination under air.

The effects of the main components of seawater on the tribological properties of Cu–9Al–5Ni–4Fe–Mn alloy sliding against AISI 52100 steel

A high strength and wear-resistance nickel-aluminum bronze alloy was successfully prepared by hot-pressing sintering. The tribological performances of it sliding against AISI 52100 steel were studied in distilled water, seawater, divalent salt solutions and monovalent salt solutions. The effects of the main components of seawater on the tribological properties were first investigated. The results show that Cu–9Al–5Ni–4Fe–Mn alloy has a lower friction coefficient and wear rate in seawater and divalent salt solutions. The Cl− and SO42− adsorbed by the surface can accelerate corrosion and promote the formation of Cu2O, Al2O3, FeOOH and Fe2O3, which has an influence on the tribological performances. The distribution of CaCO3 and Mg(OH)2 on the surface also plays an important role in the reduction of the friction coefficient and wear rate. In addition, many substances transfer from the alloy to the steel surface and form a transfer layer during the friction process.

Friction and wear behavior of nanoeutectic Fe1.87C0.13 under air and vacuum conditions

In this paper, the tribological behavior of nanoeutectic Fe1.87C0.13 alloy and its coarse-grained-eutectic counterpart under air and vacuum was investigated. The results showed that the wear rate of both alloys was lower in air than in vacuum, and their friction coefficient was related to applied load and testing atmosphere. The nanoeutectic Fe1.87C0.13 alloy exhibited lower wear rate than the coarse grained counterpart in both environments. The wear rate of both alloys increased but the friction coefficient decreased with increasing applied load under both air and vacuum. The dominant wear mechanisms were adhesion wear in vacuum but oxidation wear along with slight delamination in air.

Facile fabrication, microstructure, and corrosion resistance of high-strength, high-hardness pure bulk aluminum

Abstract High-strength pure bulk aluminum was fabricated by mechanical alloying and press forming, and its electrochemical properties and corrosion behavior in 0.5 M NaCl solution were investigated by means of potentiodynamic polarization and electrochemical impedance spectroscopy. Microstructural characterizations revealed that in addition to a Vickers hardness of 144 HV, the refined grain (0.2–1 μm) enhanced tensile and yield strengths to 560 and 520 MPa, respectively. Electrochemical data demonstrated that pure Al exhibited higher corrosion resistance than its alloys AA5083 and AA2024. Ultrafine, compact structure and homogeneous composition ensured a dense film formation during passivation. Moreover, the defect-free passive film protects the substrate by providing a high barrier against the aggressive chloride ions.