Ta-C coating is a non-hydrogen carbon element coating, also known as tetrahedral amorphous diamond coating. It has a high sp/sp2 bond ratio, with the sp3 diamond content ranging from 65% to 85%, and a Vickers hardness of up to 5000-7000 HV. Ta-C exhibits transparency, and when the coating thickness is less than 1 µm, the workpiece will display a rainbow color due to light interference. As the coating thickness increases, the color changes to gray-black. The excellent anti-adhesion properties and high hardness of Ta-C coating play a significant role in the mold and cutting tool industries.