Controllable fabrication and mechanical properties of C/C–SiC composites based on an electromagnetic induction heating reactive melt infiltration

Twill multidirectional carbon-fiber-reinforced carbon and silicon carbide composites (i.e., C/C-SiC) were prepared via chemical vapor infiltration combined with reactive melt infiltration process. The effect of heat treatment (HT) on the microstructure and mechanical properties of C/C-SiC composites obtained by C/C preforms with different densities was thoroughly investigated. The results show that as the bulk density of C/C preforms increases, the thickness of the pyrolytic carbon (PyC) layer increases and open pore size distribution narrows, making the bulk density and residual silicon content of C/C-SiC composites decrease. Moreover, the flexural strength and tensile strength of the C/C-SiC composites were improved, which can be attributed to the increased thickness of the PyC layer. The compressive strength reduces due to the decrease of the ceramic phase content. HT improves the graphitization degree of PyC, which reduces the silicon-carbon reaction rate and thereby the content of the SiC phase. HT induces microcracks and porosity but not obviously affects the mechanical properties of C/C-SiC composites. However, the negative impact of HT can be compensated by the increased density of the C/C preforms.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of density and heat treatment of C/C preforms on microstructure and mechanical properties of C/C–SiC composites

Wang

Wen

et al. 2022

“…7 C/SiC composites materials, which were listed as one of the hot-topic research, especially in aerospace applications, also confront the problem of the high-temperature oxidation in the noninert environment. [8][9][10] It was still a big challenge for the free carbon contained composites because carbon reduction might induce the performance loss or failure. The onset temperature for oxidation of the free carbon is much lower than that of the other phases, thus the existence of the free carbon accelerated the percolation process through the ceramics matrix such as SiC, SiOC and SiCN, which creates micro-pores/cracks and leads to a catastrophic loss of oxidation resistance.…”

Section: Introductionmentioning

confidence: 99%

Zr‐doped SiOC ceramics fibers and the high‐temperature thermal performance

Rui

Qiu

et al. 2023

Silicon‐containing ceramics fibers are ideal candidates for thermal resistance due to their incomparable thermo‐stability and chemical stability. Research into anti‐oxidation behavior of silicon‐containing ceramics through metal elements doping is important for the application in extreme high‐temperature environment. Thus, uniform belts‐like Zr‐doped SiOC ceramics fibers were successfully prepared by electrospinning and polymer‐derived ceramics routine with polycarbosilane (PCS) and zirconium butoxide as precursors. The morphology and dimension of the fibers were conveniently controlled by tuning PCS concentration, types of spinning additives and pyrolysis temperature. The ceramics fibers were composed of SiC, ZrO2 and SiO2 crystals, accompanied with amorphous SimZrnCxOy. The structure and compositions realized the excellent thermal stability above 1300°C and the enhanced flexibility. The obtained fibers maintained ultra‐low thermal conductivity of .038–.053 W/(m·K). Thus, the materials were anticipated to be ideal for the thermal insulation up to 1400°C or higher.

“…C/C‐SiC composites have the advantages of low density (<2.5 g/cm 3 ), high temperature resistance, high strength, high toughness, high thermal conductivity, excellent resistance to oxidation or corrosion and high tribological performance, which have become a new generation of friction materials 1–3 . Compared with PIP and CVI process, liquid silicon infiltration (LSI) process has advantages of short preparation cycles and low cost, which is widely used to prepare C/C‐SiC composites as friction material 4 .…”

Section: Introductionmentioning

confidence: 99%

“…

INTRODUCTIONC/C-SiC composites have the advantages of low density (<2.5 g/cm 3 ), high temperature resistance, high strength, high toughness, high thermal conductivity, excellent resistance to oxidation or corrosion and high tribological performance, which have become a new generation of friction materials. [1][2][3] Compared with PIP and CVI process, liquid silicon infiltration (LSI) process has advantages of short preparation cycles and low cost, which is widely used to prepare C/C-SiC composites as friction material. 4 Despite the relatively lower mechanical properties caused by silicon corrosion and expansion of residual silicon, it completely meets the requirements of friction materials and has been applied to sports cars, trucks, trains, and so on.

…”

mentioning

confidence: 99%

Effect of h‐BN addition on friction and wear properties of C/C‐SiC composites fabricated by LSI

Niu

Chen

et al. 2021

Hexagonal boron nitride (h‐BN) has excellent oxidation resistance, self‐healing function, and self‐lubricating properties, which can significantly improve the oxidation resistance of C/C‐SiC composites in low or medium temperature condition and affect their tribological properties and mechanisms. In this work, C/C‐SiC and C/C‐BN‐SiC composites were prepared by the same molding, carbonization and liquid silicon infiltration (LSI) process and the influences of h‐BN addition on their microstructure, tribological properties, and mechanisms were investigated. h‐BN addition can promote the formation of friction film and reduce the oxidation wear of the composites. Compared with C/C‐SiC composites, due to more lubricant components and different matrix structure, the C/C‐BN‐SiC composite shows lower wear rate (reduced by 53%) and moderate rather than too high coefficient of friction (CoF) and its CoF is less influenced by braking velocity. Moreover, the friction process is more stable and does not appear clamping stagnation phenomenon in high braking speed condition.