Vacuum ultraviolet/atomic oxygen erosion resistance of amorphous Si0.26C0.43N0.31 coating
An amorphous silIcon carbonltride (Si1-x_yCxNy5, x = 0.43, Y = 0.31) coating was deposited on polyimide substrate using the magnetron-sputtering method. Exposure tests of the coated polyimide in atomic oxygen beam and vacuum ultraviolet radiation were performed in a ground-based simulator. Erosion kinetics measurements indicated that the erosion yield of the SIO.16CO.43No.31 coating was about 1.5x and 1.8 x 10-26 cm3/atom during exposure In single atomic oxygen beam, simultaneous atomic oxygen beam, and vacuum ultraviolet radiation, respectively. These values were 2 orders of magnltude lower than that of bare polyimide substrate. Scanning electron and atomic force microscopy, X-ray photoelectron spectrometer, and Fourier transformed infrared spectroscopy investigation indicated that during exposures, an oxide-rich layer composed of SI02 and minor SI-C-O formed on the surface of the SI0.25C0.43N0.31 coating, which was the main reason for the excellent resistance to the attacks of atomic oxygen. Moreover, vacuum ultraviolet radiation could promote the breakage of chemical bonds with low binding energy, such as C-N, C = N, and C-C, and enhance atomic oxygen erosion rate slightly.