Effect of CVD-SiC Interface Modification Coating on the Mechanical Properties of C_f/SiC Composite Prepared by Gaseous Silicon Infiltration Process

• Main Authors: LIU Rong-jun, CAO Ying-bin, YANG Hui-yong, YAN Chun-lei, LONG Xian-hai
• Format: Article
• Language: zho
• Published: Journal of Materials Engineering 2018-01-01
• Series: Journal of Materials Engineering
• Subjects: CVD SiC; interface modification coating; GSI; C_f/SiC composite; mechanical property
• Online Access: http://jme.biam.ac.cn/CN/Y2018/V46/I1/37
• ISSN: 1001-4381; 1001-4381

The interface plays a key role on the mechanical properties of C_f/SiC composite prepared by GSI process. The ideal interface should not only prevent carbon fiber from being etched by Si vapor, but also adjust the bonding force between C fiber and SiC matrix. SiC coating prepared by CVD was chosen as the interface and its effect on the mechanical properties and fracture features of GSI C_f/SiC composite was discussed, and the influencing mechanism was analyzed. The results show that GSI C_f/SiC composite without CVD-SiC interface has poor mechanical properties, exhibiting brittle fracture feature. The bending strength, elastic module and fracture toughness are 87.6MPa, 56.9GPa and 2.1MPa&#183;m^1/2, respectively. The mechanical properties of GSI C_f/SiC increase with the increase of the thickness of CVD-SiC coating at first, then decrease with the continuous increase of the thickness of CVD-SiC coating. The C_f/SiC composite with 1.1<i>μ</i>m thickness of CVD-SiC coating has the best mechanical properties, and the bending strength, elastic module and fracture toughness are 231.7MPa, 87.3GPa and 7.3MPa&#183;m^1/2, respectively. The action mechanism of CVD-SiC interface coating on the composite is mainly on the three aspects:load transfer, preventing C fiber from being etched by Si and adjusting fiber/matrix bonding status.