Elaboration and Experimental Characterizations of Copper-Filled Polyamide Micro-Composites for Tribological Applications

Abstract

Polyamide 66 (PA66) has been used for dynamic bearing applications due to its good wear and abrasion resistance, hardness, and rigidity. PA66/copper micro-composites were studied with respect to micro-mechanical, tribological, and structural properties. A mixing step followed by injection molding was used to develop the different composites: PA66+5 wt.% Cu, PA66+10 wt.% Cu, and PA66+15 wt.% Cu. The morphological aspects of the composites were studied using scanning electron microscopy and microtomography. Good dispersion and adhesion of Cu particles across the matrix were also seen. DSC analysis showed a slight improvement in the % of crystallinity and thermal characteristics of the composites, particularly with 5 wt.% filler. Additional crystallization enhanced the tensile performance of the composites, including the modulus, elongation at break, and tensile strength. Nanoindentation tests also indicated an increase in indentation hardness and elastic modulus as a function of the filler fraction. A pin-on-disk tribometer was used to study the friction and wear properties of neat PA66 and copper-filled PA66 composites. It was found that the composite with 5 weight percent copper had the best wear resistance. A progressive decrease in the friction coefficient was also seen. Copper filler increases hardness and may effectively reduce the temperature at contact interfaces during rotating cycles.