Third Body Behavior During Dry Sliding of Cold-Sprayed Al-Al2O3 Composites: In Situ Tribometry and Microanalysis

Reciprocating sliding wear experiments were conducted on cold-sprayed pure aluminum and Al-22.6 wt% Al2O3 coatings using a custom-built in situ tribometer. Using a transparent sapphire counterface for the wear tests, the dynamic behavior of third body material in the contact was optically observed. The presence of Al2O3 particles led to greater stability of the transfer films adhering to the sapphire counterface, as well as greater stability of the friction coefficient and lower wear rates. Ex situ microanalysis of material in the wear tracks and transfer films suggests that the presence of Al2O3 particles promoted strain localization during sliding. This produced more uniform third body microstructures and protected the underlying aluminum matrix from deformation, which slowed the rate of transfer to the counterface.