Effect of Magnetic Field State on Magnetron Sputtered Cr Coatings

Ion density,electron density,and electron temperature(EED) of the magnetron sputtering plasma with an unclosed or closed magnetic field were measured during sputtering Cr in an Ar atmosphere.It was showed that the unclosed state plasma exhibited a low density;while closed state plasma exhibited much more charged particles in the center of the vacuum chamber.It was found that the deposition rate of Cr under the closed state was similar to the unclosed state at the same target current.Cr coatings deposited in the unclosed state exhibited large columnar grains and rough surfaces with protuberances.On the other hand,the interruption of the large columnar grain growth accompanied denser microstructure and a smoother surface was observed in the coating obtained in the closed state.