The Effect of the Polymer Structure in Composite Alumina/Polyetheretherketone Coatings on Corrosion Resistance, Micro-mechanical and Tribological Properties of the Ti-6Al-4V Alloy

Abstract

This paper describes ways of improving the tribological properties of the Ti-6Al-4V titanium alloy at room and elevated temperatures by electrophoretic deposition of Al 2 O 3 /PEEK708 composite coatings and postheat treatment. The microstructure of the coating components and the coatings was examined by scanning and transmission electron microscopy as well as x-ray diffractometry. The influence of cooling rate after heating of the coated alloy on the PEEK structure and coating surface topography was investigated. It was found that slow cooling with a furnace produced a semi-crystalline structure, whereas fast cooling in water generated an amorphous polymer structure. The semi-crystalline coatings exhibited a more developed surface topography than the amorphous ones. The coatings with a semi-crystalline structure revealed higher scratch resistance than the amorphous ones. The corrosion resistance of the uncoated and coated specimens was examined using electrochemical techniques in a 3.5 wt.% NaCl aqueous solution. Both coatings increased the corrosion resistance of the alloy. The friction and wear properties of the coated specimens against an alumina ball in dry sliding contact at room temperature and elevated temperatures of 150 and 260°C at ball-on-disk were examined. Both amorphous and semi-crystalline coatings increased the wear resistance and decreased the friction coefficient of the titanium alloy at room temperature. In addition, the semi-crystalline coating was also very effective in improving the titanium alloyÕs tribological properties at elevated temperatures. The obtained results clearly show that the composite alumina/PEEK coatings are promising for tribological applications in mechanical engineering.

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

“…[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.…”

“…[18] Unfortunately, virgin PEEK and some PEEK-based composites, despite excellent mechanical properties and wear resistance, have a relatively high COF. [7,14,16,19] In previous works, [7,14,16] the COF of coatings obtained in a ball-on-disc test during dry friction in cooperation with an Al 2 O 3 ball at RT was 0.27, 0.26, and 0.25 for the PEEK 708, Si 3 N 4 /PEEK 708, and Al 2 O 3 /PEEK 708 coatings, respectively. In another work, [19] the COF of PEEK in a ball-on-disc test during dry friction in cooperation with a bearing steel ball was around 0.25.…”

“…These may be carbon fibers [11] or glass fibers [12] as well as various particles such as Si 3 N 4 , [13,14] ZrO 2 , [15] or Al 2 O 3 . [16] For example, Wang et al [17] proved that the addition of SiC whiskers in a low content of 1.25 wt pct resulted in a decrease in the PEEK wear index. In terms of mixing and processing, reinforcing phases in the form of spherical or spherical-like particles are more favorable than fibers.…”

Process Optimization of Via Plug Multilevel Interconnections in CMOS Logic Devices

“…The resistivity of each film is shown in Table 1, and the deposition conditions are shown in Table 2. The resistivity was obtained by depositing 5000 Å of plasma-enhanced tetraethylorthosilicate (PETEOS) on the bare wafer, 200 Å of IMP Ti [34,35], 100 Å of CVD TiN, and 300 Å of IMP TiN [34], and measuring the sheet resistance using an Omnimap [36][37][38][39]. The resistivity of each film is shown in Table 1, and the deposition conditions are shown in Table 2.…”

“…Thus, the possibility of W residue remaining on the wafer edge after the W CMP process was fundamentally excluded. Deposition conditions at this time were SiH 4 0.025 slm, H 2 6 slm, and WF 6 0.28 slm [34,39,40]. The temperature was 395 • C, and the SiH 4 reduction time of the W seed formation step was 12 s [41,42].…”