Diamond/SiC composites were prepared by vacuum silica vapor-phase infiltration of in situ silicon–carbon reaction, and the thermophysical properties of the composites were modulated by controlling diamond graphitizing. The effects of diamond surface state and vacuum silicon infiltration temperature on diamond graphitization were investigated, and the micromorphology, phase composition, and properties of the composites were observed and characterized. The results show that diamond pretreatment can reduce the probability of graphitizing; when the penetration temperature is greater than 1600 °C, the diamond undergoes a graphitizing phase transition and the micro-morphology presents a lamellar shape. The thermal conductivity, density, and flexural strength of the composites increased and then decreased with the increase of penetration temperature in the experimentally designed range of penetration temperature. The variation of thermal expansion coefficients of composites prepared with different penetration temperatures ranged from 0.8 to 3.0 ppm/K when the temperature was between 50 and 400 °C.

Modulating the thermophysical properties of diamondSiC composites via controlling the diamond graphitization
    Abstract
    1 Introduction
    2 Experimental procedures and characterization
        2.1 Raw materials
        2.2 Composites preparation
        2.3 Characterization
    3 Results and discussion
        3.1 Phase compositions and microstructure
        3.2 Density
        3.3 Thermal conductivity
        3.4 Coefficient of thermal expansion
        3.5 Bending strength
    4 Conclusions
    Acknowledgements 
    References

• Xulei Wang(School of Materials Science and Engineering, Zhengzhou University of Aeronautics, 450046 Zhengzhou, People’s Republic of China) Corresponding author
• Yikang Li(School of Materials Science and Engineering, Zhengzhou University of Aeronautics, 450046 Zhengzhou, People’s Republic of China)
• Yabo Huang(School of Materials Science and Engineering, Zhengzhou University of Aeronautics, 450046 Zhengzhou, People’s Republic of China)
• Yalong Zhang(School of Materials Science and Engineering, Zhengzhou University of Aeronautics, 450046 Zhengzhou, People’s Republic of China)
• Pei Wang(Henan Key Laboratory of High Performance Carbon Fiber Reinforced Composites, Institute of Carbon Matrix Composites, Henan Academy of Sciences, Zhengzhou 450046, China)
• Li Guan(School of Materials Science and Engineering, Zhengzhou University of Aeronautics, 450046 Zhengzhou, People’s Republic of China)
• Xinbo He(Institute for Advanced Materials and Technology, University of Science and Technology Beijing, 100083 Beijing, People’s Republic of China)
• Rongjun Liu(College of Aerospace and Materials Engineering, National University of Defense Technology, 410073 Changsha, People’s Republic of China)
• Xuanhui Qu(Institute for Advanced Materials and Technology, University of Science and Technology Beijing, 100083 Beijing, People’s Republic of China)
• Xiaoge Wu(School of Materials Science and Engineering, Zhengzhou University of Aeronautics, 450046 Zhengzhou, People’s Republic of China)