It is usually formed by direct sputtering of carbon atoms from a graphite target. And can be coated at room temperature, the range of substrate selection is relatively wide, break through the original coating on the substrate, such as some non-metallic substrate rubber, plastic, ceramic and so on can be coated. The content of diamond SP3 in TaC coating is high, up to 80%. However, the internal stress of this kind of coating is large and the brittleness is high. Usually, the coating can not be deposited too thick, so the application scope is relatively limited.