Yes, titanium parts can undergo various surface treatments after CNC milling to enhance their properties and performance:

l Anodizing: Creates a hard, oxide layer on the titanium surface, improving corrosion resistance, wear resistance, and aesthetics.  

l PVD Coatings: Applies thin coatings like titanium nitride (TiN) or titanium aluminum nitride (TiAlN) to enhance hardness, wear resistance, and corrosion resistance.

l Heat Treatment: While titanium doesn't respond to traditional heat treatments like steel, certain heat treatments can be applied to specific titanium alloys to modify properties like strength or ductility.

l Surface Finishing: Processes like polishing, bead blasting, or sandblasting can improve surface finish and appearance.

The choice of surface treatment depends on the specific application and desired properties of the final product.