Investigation of tribological properties of Al 2O 3-polyimide nanocomposites

Abstract

Polyimide (PI) nanocomposites with different proportions of nanoparticle Al 2O 3 were made by compression molding at elevated temperature. The mechanical and tribological properties of the resulting PI-based nanocomposites were investigated. The bending strength and microhardness of the nanocomposite specimens were determined, and the tribological behavior of the nanocomposite blocks in dry sliding against a plain carbon steel ring was evaluated on an M-2000 friction and wear tester. The morphologies of the worn nanocomposite surfaces and transfer films on the counterpart steel ring were observed on a scanning electron microscope. Results indicated that the PI-based nanocomposites with appropriate proportions of nanometer Al 2O 3 exhibited lower friction coefficient and wear volume loss than PI under the same testing conditions. The nanocomposite containing 3.0wt.%–4.0wt.% nanometer Al 2O 3 registered the lowest wear volume loss under a relatively high load. The differences in the friction and wear behaviors of PI and PI–Al 2O 3 nanocomposites were attributed to the differences in their worn surface morphologies, transfer film characteristics, and wear debris features. The agglomerated abrasives on the worn composite and transfer film surfaces contributed to increase the wear volume loss of the nanocomposites of higher mass fractions of nanometer Al 2O 3.