The tribological behavior of micrometer and nanometer TiO₂ particle‐filled poly(phthalazine ether sulfone ketone) composites

Abstract

Micrometer and nanometer TiO 2 particlefilled poly(phthalazine ether sulfone ketone) (PPESK) composites with various filler volume fractions from 0.5 to 7.5 vol % were prepared by heating compression molding. The friction and wear behaviors of the PPESK composites were evaluated using the block-on-ring test rig by sliding PPESKbased composite blocks against a mild carbon steel ring under dry friction conditions. The wear debris and the worn surfaces of the PPESK composites filled with micrometer and nanometer TiO 2 particles were investigated by using a scanning electron microscope (SEM), while the structures of PPESK composites and wear debris were analyzed with IR spectra. Experimental results show that antiwear properties of the PPESK composites can be improved greatly by filling nanometer TiO 2 particles, and the friction coefficient decreases when the filler volume fraction is below 2.5%, but when the filler volume fraction is above 2.5% the friction coefficient increases gradually with increasing filler volume fraction. In the case of micrometer TiO 2 filler, wear rates increase with increasing filler volume fractions under identical test conditions, and the friction coefficients are less sensitive to the filler volume fraction. It was also found that the wear mechanism of micrometer TiO 2 particle-filled PPESK is mainly severe adhesion and abrasive wear, while that of nanometer TiO 2 particle-filled PPESK is mainly slight abrasive wear. In the former case, there are no transfer film formed on the surface of the counterpart steel, and wear debris are in the form of long and large ribbon. While in the latter case, the wear debris was granule and their size was about 10 m. In case of 1 vol % nanometer TiO 2 particlefilled PPESK composites, the transfer film was fairly thinner and smoother, and the transfer film provided better coverage on the surface of steel ring, while that of 7.5 vol % was thicker and discrete. These account for the different friction and wear behavior of micrometer and nanometer TiO 2 particle-filled PPESK composite.

Polymer and ceramic nanocomposites for aerospace applications

“…Shao et al (Shao et al 2004) found that the frictional coefficient and wear rate decreased rapidly (Fig. 14) when 1 vol% nano-TiO 2 particles were added to PPESK copolymer.…”

Influence of boric acid additive size on green lubricant performance

“…Powder lubricants have been known to: (i) adhere to surfaces to form a protective boundary layer that prevents wear (Johnson & Vaughn 1956;Lancaster 1965Lancaster , 1966Heshmat 1995;Dareing & Atluri 1997), (ii) act as a lubricant in sliding contacts by accommodating relative surface velocities (Godet et al 1980;Godet 1984;Heshmat & Dill 1992;Heshmat 1995;Brendle et al 1996;Higgs et al 1999), and (iii) lubricate at high temperatures (Centers 1987;Heshmat & Shapiro 1989;Heshmat 1991a;Heshmat & Dill 1992;Heshmat & Walton 1993;Higgs et al 1999;Higgs & Tichy 2004). Several of these lubricants-molybdenum disulphide, tungsten disulphide, titanium oxide and boron nitride-were evaluated for their lubrication behaviour at a variety of sizes and found to exhibit excellent tribological performance (Prasad & Zabinski 1993;Shao et al 2004;Hu 2005;Hu et al 2005;Ilie & Tita 2008;Shankara et al 2008). Due to similar health, economic, environmental, and disposal issues encountered with liquid lubricants, efforts are being made to develop and implement powder lubricants that come from natural resources.…”

“…In addition, despite several patents (Erdemir 1995(Erdemir , 2004 on the subject, there are no studies in the archival literature that quantitatively investigate the performance of boric acid particle additives in the colloidal size range. In the literature, considerable efforts have been made to study the effect of powder lubricant size on system performance at both the microscale and submicro/nanoscale (Shao et al 2004;Hu 2005;Hu et al 2005;Ilie & Tita 2008). Sub-micrometric forms of these powder lubricants have been synthesized using chemical vapour deposition, liquid precipitation, electronic chemistry deposition, thermal desulphurization and mechanical grinding or milling.…”

Tribological properties and insulation effect of nanometer TiO2 and nanometer SiO2 as additives in grease

“…Several researches are about the influences of nanoparticles on enhancing tribological characteristics [6][7][8]. Many articles have been carried out on TiO 2 and SiO 2 as coating materials [9][10][11][12][13][14] or reinforcement in composite materials [15,16] for achieving better tribological performance. Some papers focus on the insulation improvement of TiO 2 in transformer oil [17,18].…”