In situ tribometry of cold-sprayed Al-Al2O3 composite coatings

► Pure Al and composite Al-Al2O3 coatings were deposited by cold spray. ► Dry sliding wear tests were conducted using an in situ tribometer. ► Observations at the interface were correlated with friction, wear, and subsurface features. ► Coatings of higher alumina volume fraction formed stable transfer films. ► Transfer film stability was linked to stable friction and low wear rates.