Characterization of DC magnetron sputtered diamond-like carbon (DLC) nano coating

Development in vapor deposition techniques over the last two decades has led to the introduction of many advanced coatings for metal-cutting tools. This paper examines the characteristics of multilayer Ti, TiN, and diamond-like carbon (DLC) coatings deposited on standard tool substrates at varying sputtering parameters and conditions, such as power density, partial pressure, substrate temperature, and reactive gases. The characteristics of films were examined using an X-ray diffractometer, Raman microscope, surface profilometer (to measure the thickness of the coating), Rockwell hardness tester (to test adhesion), and a micro hardness tester. The pin-on-disc test setup was used to find the coefficient of friction of the coatings. The results indicated that a graded multilayer coating showed better adhesion to the substrates. It was observed that higher target power density resulted in an increase of micro hardness and crystalline planes of coating. Lattice constant matching among layers of coating, proper substrate preparation, and a sequence of cleaning processes are the crucial factors for the enhancement of adhesion strength.