The invention discloses a preparation method of a high
hardness zirconium nitride hard coat and relates to a preparation method of a hard coat, which comprises the following steps: matrix pretreatment: hard
alloy matrix is washed and dried after being ground and polished; and the
sputter deposition is carried out after the pre-
sputtering is performed. A method by adopting magnetic control
sputtering method to control the
process conditions such as the
atmosphere, the matrix temperature, the matrix bias and the like of the
sputter deposition so as to prepare the
zirconium nitride hard coat on the surface of the hard
alloy matrix is adopted to improve the
hardness of the
zirconium nitride coat. DC power is adopted to perform the magnetic control
sputter deposition on the surface of the hard
alloy matrix which is mechanically polished, washed by ultrasonic and washed and processed by
ion source, the total pressure is controlled at 0.3 to 0.5 Pa, the flow rate of the
nitrogen is 15 to 20 percent, DC power of the Zr target is 250 to 300W, the matrix temperature is 300 to 450 DEG C, the matrix bias
voltage is minus 50 to 100V, the deposition time is 90 to 120 minutes, and the coat has high
hardness of more than 30 GPa.