Ta-C coating is a non-hydrogen carbon element coating, also known as tetrahedral amorphous diamond-like carbon (TAC) coating. It has a high ratio of sp to sp2 bonds, with sp3 diamond content ranging from 65% to 85%, and a Vickers hardness of up to 5000-7000 HV. Ta-C exhibits some 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 transitions to gray-black. Its excellent adhesion resistance and high hardness make Ta-C play a crucial role in the mold and cutting tool industries.