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  • Effect of microstructure on...
    Chen, Zhao ke; Wang, Lin jing; Wang, Haoran; Gong, Feng qiang; Xiong, Xiang

    Surface & coatings technology, 12/2019, Letnik: 380
    Journal Article

    SiC coatings were prepared by chemical vapor deposition at 1050 °C, 1100 °C, 1150 °C, and 1200 °C by using methyltrichlorosilane (MTS, CH3SiCl3) as the precursor. The compositions, microstructures, and deposition kinetics of the coatings were studied. The results show that the main constituent of the as-prepared coatings is 3C–SiC with a small amount of free C at deposition temperatures above 1100 °C. The coating has a regular fine-grain structure at 1050 °C, umbrella-shaped structure at 1100 °C, and columnar structure at 1150 °C and 1200 °C with the deposition process being controlled by surface kinetics and diffusion kinetics, respectively. The impact resistance was tested using a Split Hopkinson Pressure Bar system. The impact resistance of the graphite substrate is improved by the as-prepared SiC coating evidently. The impact strength of the coating sample increases with increasing deposition temperature, reaching the maximum at 1150 °C, and declines slightly at 1200 °C. The stress-strain curves under dynamic impact resistance loading, and the surface morphologies and microstructures resulting from the impact tests of the different SiC coatings are discussed in detail. The factors affecting impact resistance are mainly the thickness and hardness values of the as-prepared coatings. •SiC coatings were prepared by chemical vapor deposition with a small amount of free C at above 1100 °C.•Impact behavior of SiC coating deposited at 1050~1250℃ were studied using a SHPB system.•Impact strength increases with increasing deposition temperature, reaching the maximum at 1150 °C, and declines slightly at 1200 °C.•The as-prepared SiC coatings evidently improve the impact resistance of the graphite substrate.•The factors affecting impact resistance are mainly the hardness and thickness values of the as-prepared coatings.