This study investigates the effect of heat treatment on the microstructure and tribological properties of TiB 2 -reinforced AlSi 10 Mg composite coatings produced by cold spraying. SEM and XRD analysis showed that the microstructure of the feedstock powder was well preserved in the as-sprayed material with uniformly distributed TiB 2 nanoparticles, some aggregated clusters, and a cellular-like network of fine eutectic Si particles embedded in an aluminum matrix. With increasing heat treatment temperature, the Si particles grew larger in size, but significantly fewer in number and a reduction in microhardness was observed due mainly to the elimination of the work hardening effect and coarsening of the Si particles.