The mechanical and tribological properties of polyetheretherketone (PEEK)- and PEEK + PTFE (polytetrafluoroethylene)-based composites loaded with and four types of nanoparticles (carbonaceous, metallic, bimetal oxide, and ceramic) under metal- and ceramic-polymer tribological contact conditions were investigated. It was found that loading with the nanofillers in a small content (0.3 wt.%) enabled improvement of the elastic modulus of the PEEK-based composites by 10–15%. In the metal–polymer tribological contact, wear resistance of all nanocomposites was increased by 1.5–2.3 times. In the ceramic-polymer tribological contact, loading PEEK with metal nanoparticles caused the intensification of oxidation processes, the microabrasive counterpart wear, and a multiple increase in the wear rate of the composites. The three component “PEEK/10PTFE/0.3 nanofillers” composites provided an increase in wear resistance, up to 22 times, for the metal–polymer tribological contact and up to 12 times for the ceramic-polymer one (with a slight decrease in the mechanical properties) compared to that of neat PEEK. In all cases, this was achieved by the polymer transfer film formation and adherence on the counterparts. The various effects of the four types of nanoparticles on wear resistance were determined by their ability to fix the PTFE-containing transfer film on the counterpart surfaces.
In this article, we present the results of the research into the characteristics of the conditions of heating and explosive destruction of Al-Cu, Fe-Ti, Fe-Cu, and Fe-Pb wires under a pulse of current with the density of 107 A/cm2. It has been shown that the energy that is deposited into the wire may depend on the relation between the thermophysical parameters and specific electric resistivity of the metals. It has been determined that under a pulse of current, the wires may explode synchronously or non-synchronously. During a synchronous explosion of wires, a single voltage pulse is generated. In the case of non-synchronous explosion, the wires explode in a succession, thus generating two voltage pulses. We suggested a dimensionless parameter that allows for predicting whether an electrical explosion of two wires of dissimilar metals is synchronous or non-synchronous. According to the research findings, non-synchronous nature of wire explosion may impact the formation of bimetallic particles through the explosion of two intertwined wires made of dissimilar metals.
Nanoparticles (NPs) possess a unique combination of physicochemical properties, which makes them promising materials for use in such fields of science and technology as materials science, biomedicine, and catalysis. This review presents data on the structural characteristics of metal, alloy, and composite NPs, as well as metals oxide, carbide, and nitride NPs, obtained by electrical explosion of wires (EEW). The main attention is paid to the relationship of the size distribution and phase composition of NPs with the EEW conditions and the parameters of the buffer medium (chemical composition, pressure) in which the explosion is performed. The analysis of the studies show that EEW makes it possible to obtain a wide range of NP-based powders.
Fe, Cu, and Ag nanoparticles, as well as Fe/Cu and Fe/Ag bimetallic nanoparticles, have been produced via the electric explosion of wires. The average size, shape, structure, chemical composition,...