Effects of carbon on phase transformation ofβ-SiC with Al2O3

Sakai, T.; Watanabe, Hideo; Aikawa, Toshihiko

doi:10.1007/bf01729040

Cited by 11 publications

(4 citation statements)

References 6 publications

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“…: +33 as sintering aids for silicon carbide powder both to enhance the densification rate and to slow down grain growth kinetic. 4,5 The sintering mechanism was determined for each of these additives considered separately and in the case of alumina, supplement adding of carbon or yttria were also performed. In these conditions, it is worth to notice that alumina together with carbon promoted silicon carbide sintering via solid-state sintering at temperature over 2000 • C 4 while alumina and yttria led to high density sintered sample via liquid phase sintering below 2000 • C. 5 In these approaches where additives are mainly oxides, the consolidation steps principally take place through liquid phase sintering, 5 giving rise to the formation of an interphase at the grain boundaries.…”

Section: Introductionmentioning

confidence: 99%

Role of boron on the Spark Plasma Sintering of an α-SiC powder

Maitre¹,

Put²,

Laval³

et al. 2008

Journal of the European Ceramic Society

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This study deals with the role of non-oxide sintering aids such as boron carbide (B 4 C) or -free boron (B) plus free carbon (C) -on the Spark Plasma Sintering treatment of silicon carbide. The results so obtained clearly show that free boron plus free carbon additions lead to the higher densification rates. This favourable behaviour with regards to the densification kinetics is accompanied by the absence of any abnormal grain growth. At the opposite, boron carbide additions do not significantly raise the densification kinetic after SPS treatment of SiC in comparison to pure silicon carbide. In this case, TEM investigations point out the formation of a borosilicate vitreous phase due to the dissolution process of B 4 C in contact with a native superficial silica layer surrounding the SiC grains. The resulting liquid phase leads to an abnormal grain growth coupled with undensifying process.

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Section: Introductionmentioning

confidence: 99%

Role of boron on the Spark Plasma Sintering of an α-SiC powder

Maitre¹,

Put²,

Laval³

et al. 2008

Journal of the European Ceramic Society

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“…As shown in Figures 7 and 10, the C f /SiC-Al 2 O 3 composite shows excellent mechanical properties (flexural strength and fracture toughness) and considerable mechanical properties of the matrix (Young's modulus and hardness) compared with previous works [6][7][8][9][10][11][12][13][52][53][54]. The good mechanical properties of the SiC-Al 2 O 3 matrix could be related to the relatively dense matrix using nano α-Al 2 O 3 as a filler, which generally acts as a sintering aid for SiC to improve the densification of the matrix [56]. A denser and higher strength matrix plays a key role in transferring stress.…”

Section: Discussionmentioning

confidence: 77%

Microstructure and Mechanical Properties of Unidirectional, Laminated Cf/SiC Composites with α-Al2O3 Nanoparticles as Filler

et al. 2022

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The effects of an α-Al2O3 nanoparticle filler in the SiC matrix on the mechanical properties and failure mechanism of the unidirectional, laminated carbon fiber-reinforced SiC composites were investigated in this work. First, α-Al2O3 nanoparticles were added to the carbon fiber bundles using a slurry impregnation method, and then the Cf/SiC composite with an α-Al2O3 nanoparticle filler (Cf/SiC-Al2O3) was fabricated using a precursor infiltration and pyrolysis method. The microstructure of the Cf/SiC-Al2O3 composite showed chemical compatibility between the α-Al2O3 and the pyrolysis SiC. The Cf/SiC-Al2O3 composite with a low porosity of ~6.67% achieved a good flexural strength of 629.3 MPa and a good fracture toughness of 25.2 MPa·m1/2. The interlaminar shear strength of the Cf/SiC-Al2O3 composite was 11.7 MPa. The SiC-Al2O3 matrix also presented a considerable Young’s modulus of 138.2 ± 8.66 GPa and hardness of 10.3 ± 1.03 GPa. Further analysis indicated that the good mechanical properties with the addition of an α-Al2O3 filler were not only related to the dense matrix and the improvement of the mechanical properties of the matrix. They also originated from the thermal residual compressive stress in the SiC matrix close to the α-Al2O3 nanoparticles caused by the thermal expansion mismatch, which could reflect and close the cracks in the matrix. The findings of this study provide more methods for designing new composites exhibiting a good performance.

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“…In recent years, many works have explored different strategies, such as tuning sintering additives and sintering conditions, for SiC synthesis for improving their fracture toughness [12][13][14]. In terms of the sintering additives, after studying the effects of additive components on the mechanical properties of pressure-less sintered SiC ceramics, Jung-Hye Eom et al [15] found that the Al 2 O 3 -Y 2 O 3 -AlN combination as additives could accelerate the β→α phase transition of SiC, which refines the microstructure and improve the flexural strength and fracture toughness of SiC.…”

Section: Introductionmentioning

confidence: 99%

Unlocking the strength: the predictions of silicon carbide fracture toughness revealed through data-driven approach

Xu,

Zhu,

Liu

et al. 2024

Mater. Res. Express

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Silicon carbide ceramics are widely used within various applications, including mechanical, chemical, aerospace and military; where the fracture toughness plays a crucial role. From the processing perspectives, the fracture toughness is controlled by the combination of starting phases and sintering conditions (including additives, atmosphere, temperature and pressure). However, the interplay of these factors makes the forward predictions of fracture toughness untreatable neither through experimentation nor physical modeling; not mention to the reverse estimations of optimal processing parameters. In this work, a data-driven strategy was proposed that firstly to predict the fracture toughness from processing parameters; and then to explore certain parameters that have large impacts on the fracture toughness. From running four different machine learning (ML) algorithms on a well-established dataset of SiC sintering recipe, it was found that the eXtreme Gradient Boosting (XGBoost) model possess the best performance with accuracy up to 88%. Further, the feature importance scores revealed that the sintering temperature and the types of sintering additives show their significant influence on fracture toughness. It was found that the sintering temperature is the most critical factor affecting the obtained fracture toughness of SiC, where the optimum temperature range is of 1800-2000°C; and also, the sintering additives of Al and Al2O3 have great influences on the obtained fracture toughness, where the optimum range of their mass fraction within the whole additives is 3-8 wt%. Finally, the developed model shows its capability to propose sintering strategy for the preparation of SiC ceramics with target fracture toughness.

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Effects of carbon on phase transformation ofβ-SiC with Al2O3

Cited by 11 publications

References 6 publications

Role of boron on the Spark Plasma Sintering of an α-SiC powder

Role of boron on the Spark Plasma Sintering of an α-SiC powder

Microstructure and Mechanical Properties of Unidirectional, Laminated Cf/SiC Composites with α-Al2O3 Nanoparticles as Filler

Unlocking the strength: the predictions of silicon carbide fracture toughness revealed through data-driven approach

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