Preparation and characterization of pure SiC ceramics by high temperature physical vapor transport induced by seeding with nano SiC particles

Deng, Yuchen; Zhang, Yaming; Zhang, Nan–Long; Zhi, Qiang; Wang, Bo; Yang, Jianfeng

doi:10.1016/j.jmst.2019.04.039

Cited by 15 publications

(6 citation statements)

References 27 publications

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“…The advanced TMMs should have the characteristics of low density, high strength, and high thermal conductivity (TC) perpendicular to the inferior mechanical properties and high CTE in outplane direction of the highly oriented graphite blocks lead to the failure under harsh service environments [11]. In order to overcome the obstacles, some studies attempted to promote the mechanical properties of the graphite-based composites by using metal and ceramic powers (such as Cu, AlN, and SiC) as reinforcements [12][13][14]. However, the huge differences between metal/ceramic powders and GF particles in size, shape, and dimension lead to the inhomogeneous distribution of metal/ceramic reinforcements in GF matrix [15], which makes the flexural strength improvement rather limited.…”

Section: Introduction mentioning

confidence: 99%

Continuous SiC skeleton reinforced highly oriented graphite flake composites with high strength and specific thermal conductivity

et al. 2022

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Highly oriented graphite-based composites have attracted great attention because of their high thermal conductivity (TC), but the low mechanical properties caused by the inhomogeneous distribution and discontinuity of reinforcements restrict the wide applications. Herein, continuous SiC ceramic skeleton reinforced highly oriented graphite flake (SiC/GF) composites were successfully prepared by combining vacuum filtration and spark plasma sintering. The effect of SiC concentration on the microstructure, flexural strength, and thermophysical properties of the composites was investigated. The GF grains in the composites exhibited high orientation with a Lotgering factor of > 88% when the SiC concentration was ⩽ 30 wt%, and the SiC skeleton became continuous with the SiC concentration reaching 20 wt%. The formation of continuous SiC skeleton improved the flexural strength of the composites effectively while keeping the TC in a high level. Especially, the composites with 30 wt% SiC exhibited the flexural strength up to 105 MPa, and the specific TC reaching 0.118 W·m2·K−1·kg·1. The composites with excellent flexural strength and thermophysical properties showed significant promise for thermal management applications.

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Section: Introduction mentioning

confidence: 99%

Continuous SiC skeleton reinforced highly oriented graphite flake composites with high strength and specific thermal conductivity

et al. 2022

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“…Table 2 presents the density, grain size, Lotgering factor, mechanical properties, and thermal conductivity at room temperature of SiC ceramics prepared by seeding with SiC nanoarrays via two-step temperature control in HTPVT. In the previous research [ 24 , 25 ], the relative density of samples was 97.8%, the flexural strength was only 309 ± 34 MPa, and the thermal conductivity was 199.68 W·m −1 ·K −1 . Compared with those results, the performance of SiC ceramics induced by SiC ordered nanoarrays has been improved.…”

Section: Resultsmentioning

confidence: 94%

“…Based on the previous research [ 25 , 26 ], in order to control the nucleation and optimize the microstructure of SiC ceramics more efficiently, we propose a new idea for preparing high-purity SiC ceramics by seeding with SiC nanoarrays. Firstly, using the porous ultra-thin AAO template, amorphous SiC films are prepared by the plasma-enhanced chemical vapor deposition (PECVD).…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Pure SiC Ceramics by HTPVT Induced by Seeding with SiC Nanoarrays

et al. 2021

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Dense SiC ceramics were fabricated by high-temperature physical vapor transport (HTPVT) growth process using SiC nanoarrays as the crystal seeds, which was obtained by vacuum heat treatment of amorphous SiC films prepared by plasma-enhanced chemical vapor deposition (PECVD) with a porous anodic aluminum oxide (AAO) template. In the HTPVT process, two-step holding was adopted, and the temperature at the first step was controlled at 2100 and 2150 °C to avoid SiC nanoarrays evaporation, and the grain size of SiC crystal increased with the increase in temperature and decrease in the pressure of Ar. The temperature of the second step was 2300 °C, and rapid SiC grain growth and gradual densification were achieved. The prepared SiC ceramics exhibited a relative density of more than 99%, an average grain size of about 100 μm, a preferred orientation along the (0 0 0 6) plane, a Vickers hardness of about 29 GPa, a flexural strength of about 360 MPa, and thermal conductivity at room temperature of more than 200 W·m−1·K−1.

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“…Bringing the thermodynamic data of each substance into Equation 5, the expressions of ΔG of Equations 1 and 2 can be obtained: ΔG 1 = 616560-353.04T + 2×8.314×Tln (P CO /P θ ) (6) ΔG 2 =679733-361.34T + 2×8.314×Tln (P CO /P θ ) (7) Taking the values of P CO as 1.01×10 1 Pa, 1.01×10 3 Pa, and 1.01×10 5 Pa, respectively, and taking the value of P θ as 1.01×10 5 Pa, and substituting the values into Equations 6 and 7, the changes of the calculated Gibbs free energy (ΔG) with the temperature (T) can be obtained (Figures 2 and 3).…”

Section: Thermodynamic Analysismentioning

confidence: 99%

“…However, due to the covalent bonding mechanism of SiC itself, its plastic deformation ability is reduced, its fracture toughness is poor, and its strength is low at room temperature. The practical application of SiC is limited [7][8]. Introducing a secondary-phase material is an effective way to improve the insufficient performance of SiC [9].…”

Section: Introductionmentioning

confidence: 99%

SYNTHESIS AND MECHANISM OF SiC-ZrC COMPOSITE POWDERS BY CARBOTHERMAL REDUCTION METHOD

Cao¹

2022

Ceramics - Silikaty

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SiC-ZrC composite powders were synthesised by the carbothermal reduction method using starch as the carbon source, zirconium dioxide as the zirconium source, and silica sol as the silicon source. The effects of the reaction temperature on the phase composition and microstructure of the SiC-ZrC composite powders were investigated. The reaction process was thermodynamically analysed and calculated, and the synthesis mechanism of the SiC-ZrC composite powder was analysed. The synthesised powder samples were characterised and analysed by X-ray diffraction, scanning electron microscopy, and other testing methods. The results show that the optimum reaction condition for the synthesis of SiC-ZrC composite powders is at 1550 °C-1600 °C for 1.5 h. A high temperature and a low pressure are beneficial in conducting the synthesis reaction. The SiC-ZrC composite powders synthesised by calcining at 1550 °C and holding for 1.5 h are mainly composed of a certain amount of whiskers, spherical particles, floc particles, and other structures. Moreover, their grain size is small (100-200 nm). The powder samples synthesised at 1600 °C produced a larger number of whiskers. The length of the whiskers was mostly 10 μm, the arrangement was complex and irregular, and a diverse microstructure was formed.

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Preparation and characterization of pure SiC ceramics by high temperature physical vapor transport induced by seeding with nano SiC particles

Cited by 15 publications

References 27 publications

Continuous SiC skeleton reinforced highly oriented graphite flake composites with high strength and specific thermal conductivity

Continuous SiC skeleton reinforced highly oriented graphite flake composites with high strength and specific thermal conductivity

Preparation and Characterization of Pure SiC Ceramics by HTPVT Induced by Seeding with SiC Nanoarrays

SYNTHESIS AND MECHANISM OF SiC-ZrC COMPOSITE POWDERS BY CARBOTHERMAL REDUCTION METHOD

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