MICROSTRUCTURE AND FLAME-RETARDANT PROPERTIES OF Ti-Cu COATING ON TC11 PREPARED VIA ELECTROSPARK DEPOSITION

With a novel high-power electrospark deposition (ESD) processing unit, Ti-Cu coatings were prepared on TC11 titanium alloy substrate using optimized processing parameters. The Ti-Cu coatings consisted of many secondary layers and metallurgically bonded to the substrate. X-ray diffraction (XRD) as well as optical microscope (OM) and scanning electron microscopy (SEM) were performed to determine the composition and microstructure of the resulting deposition. The superficial layer of the Ti-Cu coating was composed of copper-titanium and aluminum-titanium intermetallics. Microhardness tests showed that the microhardness of Ti-Cu coating was more twice than that of the substrate. The flame-retardant properties of TC11 substrates with Ti-Cu coatings were evaluated through the laser ablation testing on the surface using a laser power of 1KW and 1.5KW with an ablation time of 10s and 5s respectively. The Ti-Cu coatings exhibited the flame-retardant properties under (1KW, 10s) ablation parameter conditions on the TC11 titanium alloys which were characterized by the phenomena of spontaneous combustion under some certain environmental conditions.