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Polytetrafluoroethylene (PTFE) has been widely used in industrial field for sealing parts. However, it is well known that PTFE is always subject to serious wear at high temperature (over 150 °C), which has become the main drawback limiting serve life of important equipment such as compressors. In this paper, a new solution is proposed for improving the wear resistance of carbon fibers-reinforced PTFE (CFRPTFE). Multilayer Ti-TiCx/DLC film is prepared and used as the counterface of CFRPTFE. Friction and wear tests at high temperature (200 °C and 250 °C) are carried out. The uncoated 17-4PH steel disks precisely polished by abrasive papers with different grain sizes are used as the reference counterface (SS80 and SS7000). It is found that by sliding against Ti-TiCx/DLC film, the tribological behaviors of CFRPTFE at high temperature can be improved. The friction coefficient between CFRPTFE and DLC under different test conditions can be kept in stable state. The wear rates of CFRPTFE reduce by 50%–70% compared to SS80, and reduction of 20%–40% can be observed when compared to SS7000. It can be found that graphitization transition at high temperature promotes the transfer layer formation and contributes to lower friction and lower wear compared to traditional processed counterface at high temperature. These significant improvements can prolong the lifetime of CFRPTFE moving parts used in high-temperature and heavy-load applications. Finally, engineering verification of the proposed friction pair is carried out in miniature oil-free high-pressure compressor. [ABSTRACT FROM AUTHOR]

Powder Bed Fusion (PBF) is an additive manufacturing technology used to produce metal-based materials. PBF materials have a unique microstructure as a result from repeated and sharp heating/cooling cycles. Many researches have been carried out on relations between processing parameters of the PBF technology, obtained microstructures and mechanical properties. However, there are few studies on the tribological properties of PBF materials at various contact conditions. This article describes previous and recent studies related to the friction performance. This is a critical aspect if PBF materials are applied to friction pair components. This paper discusses wear rates and wear mechanisms of PBF materials under dry friction, boundary lubrication and micro-motion conditions. PBF materials have higher hardness due to fine grains. PBF materials have a higher wear resistance than traditional materials due to their solid solution strengthening. In addition, hard particles on the surface of PBF components can effectively reduce wear. The reasonable combination of process parameters can effectively improve the density of parts and thus further improve the wear resistance. This review paper summarized the wear behavior of PBF materials, the wear mechanism of metal materials from dry friction to different lubrication conditions, and the wear behavior under fretting wear. This will help to control the processing parameters and material powder composition of parts, so as to achieve the required material properties of parts and further improve the wear performance. [ABSTRACT FROM AUTHOR]

This study explored the modulatory role of independent/interdependent self-construal on ensemble perception. Two experiments were conducted to study the effect of self-construal on ensemble coding of multiple-face identities (Experiment 1) and dot size (Experiment 2) separately. Before the implicit ensemble perception task, participants in both experiments were either primed with independent or interdependent self-construal via a well-validated pronoun circle task, in which they were exposed to either singular (" I ," " me ," and " my ") or plural (" We ," " us ," and " our ") pronouns in essays. The results showed that interdependent self-construal (vs. independent self-construal) featured as global processing and emphasizing interconnectedness with others enhanced the ensemble coding of high-level features (e.g., identity in Experiment 1) but not of low-level features (e.g., size in Experiment 2). To the best of our knowledge, this study was the first to investigate the role of self-construal on ensemble representations. In sum, the results of the current study supported the domain-specific mechanism of ensemble perception on one hand, and extended the effect of self-construal on single face recognition to multiple face recognition on the other hand.