Thermal conductivity and bending strength of SiC composites reinforced by pitch-based carbon fibers

Abstract

In this work, pitch-based carbon fibers were utilized to reinforce silicon carbide (SiC) composites via reaction melting infiltration (RMI) method by controlling the reaction temperature and resin carbon content. Thermal conductivities and bending strengths of composites obtained under different preparation conditions were characterized by various analytical methods. Results showed the formation of SiC whiskers (SiCw) during RMI process according to vapor—solid (VS) mechanism. SiCw played an important role in toughening the Cpf/SiC composites due to crack bridging, crack deflection, and SiCw pull-out. Increase in reaction temperature during RMI process led to an initial increase in thermal conductivity along in-plane and thickness directions of composites, followed by a decline. At reaction temperature of 1600 °C, thermal conductivities along the in-plane and thickness directions were estimated to be 203.00 and 39.59 W/(m·K), respectively. Under these conditions, bending strength was recorded as 186.15±3.95 MPa. Increase in resin carbon content before RMI process led to the generation of more SiC matrix. Thermal conductivities along in-plane and thickness directions remained stable with desirable values of 175.79 and 38.86 W/(m·K), respectively. By comparison, optimal bending strength improved to 244.62±3.07 MPa. In sum, these findings look promising for future application of pitch-based carbon fibers for reinforcement of SiC ceramic composites.

Mechanical and tribological properties of SiC whisker‐reinforced SiC composites via oscillatory pressure sintering

“…Besides, the introduction of the second phase into the ceramics can significantly improve the mechanical properties of the ceramic matrix composites. [12][13][14][15][16][17] With high strength, hardness, elastic modulus, excellent aspect ratio, and good chemical stability, SiC whiskers (SiCw) are used as significant toughening materials for metal and ceramic matrix composites. For instance, Song et al 18 coated a layer of phenolic resin on the surface of SiCw to strengthen SiC ceramics; they found that the fracture toughness and strength of SiC-15 wt% SiCw composites were increased by 45% (from 200 to 290 MPa) and 75% (from 3.2 to 5.6 MPa⋅m 1/2 ), respectively, compared to the pure SiC ceramics.…”

A novel approach for manufacturing of layered, ultra-refractory composites using pliable, short fibre-reinforced ceramic sheets

“…To improve fracture properties of the UHTCs, short and long carbon or silicon carbide fibres have been added [8][9][10][11][12][13][14][15]. These composites are called ultra-hightemperature ceramic matrix composites (UHTCMCs).…”

“…Fig 13. Morphologies of graded sample (L2) composed of alternation 20% C f -reinforced layers (A) and 0% C f layers (B).…”

Mechanical and thermal properties of δ‐RE4Hf3O12(RE = Yb, Lu)

“…Silicon carbide fiber reinforced silicon carbide ceramic matrix composites (SiC f /SiC CMCs) are promising candidates for application as hot section components in future aeroengines due to their inherently low weight, high-temperature capabilities, and tolerance of damage. [1][2][3][4] Environmental barrier coatings (EBCs) are increasingly important, and they are being developed to protect hotsection components from degradation in high-temperature water vapor and molten silicate deposits environments. 5,6 Advanced coating design concepts are currently explored and tested, including multilayered and integrated thermal and EBCs (TEBCs).…”

“…The apparent densities of δ-Yb 4 Hf 3 O 12 and δ-Lu 4 Hf 3 O 12 are measured as 9.73 and 9.88 g/cm3 , respectively. Samples were obtained with relative densities higher than 97%.…”