Enhanced metallic targets prepared by spark plasma sintering for sputtering deposition of protective coatings

Metallic Ti, Al and Ti-Al sputtering targets with diameter of 50.8 mm and thickness of 3.175 mm were developed successfully by spark plasma sintering (SPS) process. SPS experiments were conducted in vacuum under 50 MPa and sintering temperatures of 1250 degrees C for Ti, 560 degrees C for Al and 1200 degrees C for Ti-Al, dwell time of 5 min, 12:2 DC pulse pattern, heating and cooling rates of 50 degrees C min(-1). The surface roughness Ra of about 0.2 mu m was obtained after mechanical polishing of the SPSed samples. The raw materials consisted of pure Ti, Al and Ti-Al 75-25 at% fine powders. XRD analysis revealed the polycrystalline nature of all the powders and SPSed samples. Ti and Ti-Al powders and SPSed Ti and Ti-Al (alpha(2)-Ti3Al) samples had hexagonal structure while Al powder and SPSed Al sample had cubic structure. SEM analysis showed irregular shaped powder particles that changed in the SPSed samples due to the recrystallization process. EDS analysis confirmed the presence of Ti and/or Al elements and minor amounts of O, Fe, Cu or Ag. The relative density of all the SPSed samples was over 97% that is close to the theoretical density. The SPSed Al sample yielded the highest electrical conductivity. The SPSed Ti-Al (Ti3Al) sample exhibited superior mechanical properties comparatively with the other samples. The SPSed targets were tested in vacuum magnetron sputtering installations proving very good behavior within deposition of thin films on various substrates. The obtained results are encouraging to use the developed targets in practical applications.