Fibre-reinforced multifunctional SiC matrix composite materials

Abstract

In the last two decades, fibre-reinforced SiC ceramic-matrix composites (CMCs) have attracted extensive interests. Owing to the designable multi-scale microstructure feature and the tailorable processing methods such as chemical vapour infiltration and polymer derived ceramics, SiC matrix composites attain great potential as multifunctional composites. Through designing the fibre, interphase, matrix and coating, the composite exhibits a multitude of functionalities which are desirable for various technological applications. Besides strengthening and toughening design of CMCs, three inspiring issues of multifunctional CMCs are receiving increasing attention, including crack self-healing, friction self-lubrication, and electromagnetic shielding and absorption, which are the key mechanisms to promote the application of CMCs in hot structures of engines and aerospace vehicles, braking pads/discs, various electronic devices, etc. The present review covers the main mechanisms on strengthening and toughening, crack selfhealing, friction self-lubrication, and electromagnetic shielding and absorption of CMCs. Key developments and future challenges in this field are summarised.

Multiscale designed SiCf/Si3N4 composite for low and high frequency cooperative electromagnetic absorption

“…To ensure insensitivity of absorption to the incidence angle, the 2D braided plain weave SiC f fabrics (0°/90°) are chosen. Inter‐bundle pores and intra‐bundle pores exist in the composite because of the bottle‐neck effect during the CVI process, which can further enhance the EM wave absorbing because of its multiple reflection effect . Furthermore, to ensure the temperature stability of the absorbing, the crossing grooved meta‐structure is designed to adjust the effective permittivity and produce a better impedance matching, leading to effectively enhanced EM wave absorbing property stability with incident angle and temperature.…”

“…EM wave absorbing materials are generally classified into two types: dielectric loss material and magnetic loss material, but the latter would suffer EM absorbing deterioration when the usage temperature exceeds their Curie points . For EM wave absorption applications at severe environments, especially for high temperatures, dielectric ceramic matrix composites (CMCs) are good candidates because of their excellent high‐temperature stability and oxidation resistance . By now, most of researches on dielectric CMCs focus on the target frequency range of X‐band (8.2‐12.4 GHz) and Ku‐band (12.4‐18 GHz).…”

“…By now, different kinds of fibers are generally implemented for tailoring the permittivity of CMCs to meet the requirements of EM wave absorption materials. It has been proved that the effective way to obtain EM wave absorption composites is to combine the EM wave absorbing fibers with wave‐transparent ceramic matrix . Numerous works have been conducted on improving the absorbing efficiency of fiber reinforced CMCs via tailoring the compositions and microstructures, but the complex permittivity of most materials would be sensitive to temperature increasing, which restricts their applications at high temperature.…”

A comparative study on Cf/PyC/SiC minicomposites prepared via CVI process for hypersonic engine application

“…Carbon fiber reinforced ceramic matrix composites (CMCs) are prime candidates for such applications because of high strength, hardness, chemical inertness, low density, and high service temperatures . Recently ceramic composites have also being evaluated for their multifunctional properties such as electromagnetic shielding, self‐healing, and self‐lubrication characteristics . A suitable fiber/matrix system and a processing route have to be selected first for the development of a CMC system for a specific application.…”

Microstructure and EMW absorption properties of CVI Si3N4–SiCN ceramics with BN interface annealed in N2 atmosphere

“…20,21 BN is the widely used interface with low complex permittivity and special layered structure in the ceramic matrix composites, 22 and the thermal conductivity of BN interface is much higher than that of Si 3 N 4 , SiC, and SiCN ceramics. The crystallization process of SiCN ceramics is closely related to phase composition and surface characteristics of substrates, so the proper substrates are important for the crystallization process of CVI SiCN ceramics.…”