Effect of the Processing and Heat Treatment Route on the Microstructure of MoS₂/Polyetheretherketone Coatings Obtained by Electrophoretic Deposition

Abstract

In this work, molybdenum disulfide nanosheets were electrophoretically co-deposited with PEEK 708 microparticles to fabricate composite coatings on Ti-6Al-4V titanium alloy substrates. Different dispersion media, pure ethanol and ethanol with the addition of cationic chitosan polyelectrolyte have been studied. The co-deposition mechanisms were indicated based on zeta potential measurements and investigation of the interaction between particles in the suspension using electron microscopy. The composite coatings deposited from the suspension containing a low amount of MoS 2 stabilized by chitosan were homogeneous. The polymer morphology changed as a result of heat-treatment from granular in the as-deposited coating into a dense, continuous matrix in the heat treated coating. The separate MoS 2 nanosheets and their packages were relatively homogeneously distributed and formed arrays that were mainly parallel to the coating surface. The coatings exhibited an amorphous structure regardless of the applied cooling rate after heating. The amorphization of the coating, slowly cooled after heating above the melting point, is due to the partial diffusion of sulfur from MoS 2 to PEEK 708 and its sulfonation. The obtained results provide new knowledge regarding the co-deposition mechanisms of MoS 2 and PEEK in the presence of chitosan and polymer sulfonating at elevated temperatures.

The Influence of Electrophoretic Deposition Parameters and Heat Treatment on the Microstructure and Tribological Properties of Nanocomposite Si3N4/PEEK 708 Coatings on Titanium Alloy

“…These two methods can also occur simultaneously as electrosteric stabilization [48]. Based on our previous studies [32,49], a cationic chitosan polyelectrolyte was used. To determine the stability of suspensions, a zeta potential of Si 3 N 4 and PEEK 708 particles were examined in pure ethanol and in ethanol-based dispersion media containing the addition of 15, 25 and 50 vol % of chitosan polyelectrolyte.…”

Nanocomposite coatings obtained by electrophoretic co-deposition of poly(etheretherketone)/graphene oxide suspensions

“…Nanocomposite performance depends on different factors such as dispersion, matrix-filler interactions, and, in case of flake and fibre reinforcements, alignment [10]. In this respect, EPD is useful to develop specific microstructures from multicomponent suspensions [14]; for instance, in the study of PEEK/MoS 2 coatings by electrophoretic codeposition, MoS 2 was found to align preferentially, parallel to the coating surface [15]. Similar preferential alignment of graphene oxide (GO) nanosheets has been reported in the EPD process [16][17][18][19][20][21].…”

Effect of Low-Friction Composite Polymer Coatings Fabricated by Electrophoretic Deposition and Heat Treatment on the Ti-6Al-4V Titanium Alloy’s Tribological Properties

“…Extensive literature exists on the EPD of different PEEK-based coatings. [35][36][37][38][39][40][41] These works and our previous experience [14,42] proved that EPD and post-EPD heat treatment is a suitable method to produce pure PEEK 708 and PEEK 708-based coatings on titanium alloy substrates for tribological applications. The previously obtained PEEK 708, [7] Si 3 N 4 /PEEK 708, [14] and Al 2 O 3 / PEEK 708 [16] coatings on the Ti-6Al-4V alloy, despite a significant improvement in wear resistance in cooperation with an Al 2 O 3 ball at RT, had a relatively high COF of 0.27, 0.26, and 0.25, respectively.…”