Abstract
Diamond films are synthesized by arc discharge plasma jet chemical vapor deposition in the methane 
atmosphere. The apparatus developed generates a stabilized plasma jet continuously for more than 12h. The plasma jet consists of hydrogen and argon. 
is used as an atmospheric gas and is mixed into the plasma jet. The plasma jet is sprayed onto a cool‐down substrate, and a diamond film is deposited on the substrate surface. By means of this method, a diamond film is deposited on a molybdenum substrate at the growth rate of 930 μm/h. The crystallinity of the diamond film measures well by means of x‐ray diffraction and Raman spectroscopy. The weight of diamond obtained by this method in a unit time seems to be almost the same as that obtained by high‐temperature and high‐pressure synthesis method.