Tribological Properties of Polyether–Ether–Ketone-Based Coating under Mixed and Boundary Aviation Kerosene-Lubrication Condition

Jihai Jiang,Geqiang Li,Cunran Zhao

doi:10.3390/coatings10010001

Abstract

Because of its excellent tribological performance, polyether–ether–ketone (PEEK)-based coatings have been used extensively under mixed and boundary water-lubrication conditions. To verify that the PEEK-based coating is applicable to aviation kerosene, one advanced coating was proposed and two typical metals, namely, alloy steel 38CrMoAlA and tin bronze ZQPb17-4-4, were selected as counterparts. Four sets of experiments that involved a scuffing (step load) and Stribeck curve (step speed), constant load, and strengthened load were carried out, which showed that the counterpart material’s properties, such as its hardness, thermal conductivity, and composition, had an important effect on the tribological performance of the PEEK-based coating. Scuffing experiments showed that the PEEK-based coating against ZQPb17-4-4 exhibited better scuffing performance. Stribeck curve experiments showed that the PEEK-based coating against 38CrMoAlA was under the mixed lubrication condition over a wider range of speeds, and wear experiments (constant load and strengthened load) showed that the PEEK-based coating against 38CrMoAlA exhibited a relatively low coefficient of friction and low wear rate. The formation and appearance of the tribofilm on the surface of the counterparts influenced the wear mechanism of the PEEK-based coating. The PEEK-based coating showed excellent properties, especially when rubbed against 38CrMoAlA.

Highlights

During normal operation of mechanical equipment, a friction pair will produce an oil film by the hydrodynamic effect
The analysis indicates that the main wear mechanism of the PEEK-based coating sliding against ZQPb17-4-4 is fatigue wear
The following conclusions could be drawn: (1) Scuffing experiments showed that the PEEK-based coating had a good scuffing resistance against

Summary

Introduction

During normal operation of mechanical equipment, a friction pair will produce an oil film by the hydrodynamic effect. The oil film will be damaged because of a start–stop, overload operation, and manufacturing assembly error, and the friction pair will be under a mixed and boundary lubrication [1]. Direct contact of rough peaks of the friction pair will result in deformation, adhesion, wear, and fatigue. The most critical approach to control friction and reduce wear is to reduce the contact number of rough peak points of a friction pair [2]. A tribofilm with a good lubrication performance can reduce the material friction coefficient and wear rate and prevent catastrophic equipment failure caused by copper burning and gluing of the friction pair [3]. To improve the durability and reliability of friction pairs, the friction and wear behaviors of materials under mixed and boundary conditions should be understood

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Results

Conclusion