Low-Temperature Sintering of Porous Silicon Carbide Ceramics with H3PO4 as an Additive

In this paper, the raw SiC powder is oxidized at high temperature (1000 °C for 4h), and a layer of SiO2oxide film is formed on the surface of SiC particles. By adding phosphoric acid, phosphoric acid reacts with SiO2at lower temperatures to form phosphate. Phosphate decomposition produces gas to create pores. At 1200 °C, the phosphate is completely decomposed into SiO2, and a large amount of gas is produced to prepare porous SiC ceramic with high porosity and high strength. The effects of H3PO4content on the phase composition, microstructure, porosity and mechanical properties of the prepared porous SiC ceramic were investigated. With the increase of H3PO4content, the porosity increased and the bending strength decreased. The results suggest that at the sintering temperature of 1200 °C, the porosity of the samples can reach 58.3%~71.2%, while the bending strength of them can reach 8.72~31.09 MPa.

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Environment-Friendly Preparation of Reaction-Bonded Silicon Carbide by Addition of Boron in the Silicon Melt

Materials ◽

10.3390/ma14051090 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1090

Author(s):

Maoqiang Rui ◽

Yaxiang Zhang ◽

Jing Ye

Keyword(s):

Mechanical Properties ◽

Silicon Carbide ◽

Bending Strength ◽

Sintering Temperature ◽

Argon Atmosphere ◽

Environment Friendly ◽

Silicon Melt ◽

Different Temperatures ◽

Carbide Ceramics ◽

Silicon Carbide Ceramics

Reaction-bonded silicon carbide ceramics were sintered by infiltration of Si and B–Si alloy under an argon atmosphere at different temperatures. The element boron was added to the silicon melt to form a B–Si alloy first. The mechanical properties of samples were improved by infiltration of the B–Si melt. The samples infiltrated with the Si-only melt were found to be very sensitive to experimental temperature. The bending strengths of 58.6 and 317.0 MPa were achieved at 1530 and 1570 °C, respectively. The sample made by infiltration of B–Si alloy was successfully sintered at 1530 °C. The relative density of the sample was more than 90%. The infiltration of B–Si alloy reduced the sintering temperature and the bending strength reached 326.9 MPa. The infiltration mechanism of B–Si alloy is discussed herein.

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Sintering of Silicon Carbide Ceramics with Co-Addition of Gadrinium Oxide and Silica and their Mechanical Properties

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.484.117 ◽

2011 ◽

Vol 484 ◽

pp. 117-123

Author(s):

Toyohiko Yano ◽

Yasutaka Horie ◽

Masamitsu Imai ◽

Katsumi Yoshida

Keyword(s):

Mechanical Properties ◽

Grain Boundary ◽

Bending Strength ◽

Sintering Temperature ◽

Applied Pressure ◽

Boundary Phase ◽

Homogeneous Distribution ◽

Carbide Ceramics ◽

Co Addition ◽

Silicon Carbide Ceramics

Effects of simultaneous addition of SiO2 and gadrinium oxide on densification of SiC ceramics were examined, and relation between microstructure and their mechanical properties were discussed. Total 11wt% of Gd2O3 and SiO2 were mixed with fine -SiC powder. The weight of Gd2O3 in (Gd2O3 + SiO2) were set as 0, 20, 40, 60, 80 and 100%. The mixture was hot-pressed at 1950oC under 40 MPa applied pressure for 1 h. In the case of 40Gd2O3 and 80Gd2O3 compositions, the effect of sintering temperature from 1900 to 2000oC was also examined. The bulk density increased with increasing Gd2O3 content at the sintering temperature of 1950oC. Bending strength of the sintered bodies also improved with increasing Gd2O3 content generally, but at 40Gd2O3 composition, the maximum over ~800 MPa was observed. Young’s modulous, Vickers hardness and fracture toughness also increased with increasing Gd2O3 content. The distribution of grain boundary phase was not homogeneous. Evaporation of additives, mainly SiO2, caused non-homogeneous distribution of grain boundary phase between outside and inside of sintered bodies. High temperature bending strength of 80Gd2O3 specimen was superior than that of 40Gd2O3 specimen.

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Effects of Additives Content on the Properties of Porous SiC Ceramics

Materials Science Forum ◽

10.4028/www.scientific.net/msf.868.89 ◽

2016 ◽

Vol 868 ◽

pp. 89-94

Author(s):

Rong Li ◽

Rong Zhen Liu ◽

Gao Jian Liu ◽

Zhi Hao Jin

Keyword(s):

Silicon Carbide ◽

Melting Point ◽

Porous Silicon ◽

Bending Strength ◽

Porous Silicon Carbide ◽

Sic Ceramics ◽

Proportional Relationship ◽

Carbide Ceramics ◽

Porous Sic ◽

Silicon Carbide Ceramics

The porous silicon carbide ceramics were fabricated by adding a variety of low melting point oxides in this paper. The additives were mullite, magnesium oxide, calcium oxide, and vanadium oxide. Effects of the additives content on the properties of porous silicon carbide ceramics were studied. The results showed that, when the additives content was greater than 2.8%, the apparent porosity, the bending strength, the permeability and the pore size were in an inversely proportional relationship with the additives content, while the content was less than 2.8%, proportional relationship was observed. When the additives content reached 2.8%, the porous SiC ceramics showed the best performances.

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Study on Preparation of Ceramic Material and its Properties

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.686.57 ◽

2014 ◽

Vol 686 ◽

pp. 57-60

Author(s):

Ya Li Liu

Keyword(s):

Fly Ash ◽

Red Mud ◽

Bending Strength ◽

Sintering Temperature ◽

Raw Materials ◽

Porous Ceramic ◽

High Strength ◽

Porous Ceramics ◽

Raw Material ◽

High Porosity

This paper introduces the classification, properties and application of porous ceramic materials, reviewed preparation of porous ceramics. Taking fly ash and red mud as the main raw material to generate porous ceramics, the paper study the influence of different proportions of raw materials, sintering temperature, porosity of porous ceramic sample rate, bending strength, and microstructure. The results show that, fly ash and red mud proportioning and sintering temperature are the main factors that influence the structure and properties of samples. The 4# sample is a kind of high porosity and high strength quality of porous ceramics.

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Fabrication of porous silicon carbide ceramics with high porosity and high strength

Journal of the European Ceramic Society ◽

10.1016/j.jeurceramsoc.2013.10.008 ◽

2014 ◽

Vol 34 (3) ◽

pp. 837-840 ◽

Cited By ~ 34

Author(s):

Weiwu Chen ◽

Yoshinari Miyamoto

Keyword(s):

Silicon Carbide ◽

Porous Silicon ◽

High Strength ◽

High Porosity ◽

Porous Silicon Carbide ◽

Carbide Ceramics ◽

Silicon Carbide Ceramics

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Joining of SiC Ceramic to Graphite Using Ni-51Cr Powders as Filler

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.1600 ◽

2008 ◽

Vol 368-372 ◽

pp. 1600-1602 ◽

Cited By ~ 1

Author(s):

Yang Wu Mao ◽

Shu Jie Li ◽

Lian Sheng Yan

Keyword(s):

High Temperature ◽

Chemical Reactions ◽

Reaction Layer ◽

Bending Strength ◽

Weld Zone ◽

High Strength ◽

Interfacial Area ◽

Three Point Bending ◽

Sic Ceramic ◽

Points Of View

Joining of SiC ceramic to graphite is important from both technical and economical points of view. High temperature brazing of recrystallized SiC ceramic to high strength graphite has been realized using Ni-51Cr (consisting of Ni + 51wt% Cr powders) powders as filler. The obtained maximum three-point bending strength of joints is 32.3MPa, which is equal to 80.8% of the strength of the graphite. Microstructure and phase analysis reveals that interdiffusions and chemical reactions take place in the weld zone. A reaction layer and an interlayer form in the interfacial area. The reaction layer, of which the thickness is about 60-100μm, is contacted with the SiC ceramic. The interlayer with the thickness of about 200μm exists between the graphite and the reaction layer. The reaction layer is mainly composed of Ni2Si, while the interlayer is mainly composed of Cr23C6 and Ni2Si.

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Preparation of Porous ZrO2-Al2O3 Composite Ceramic with High Strength and Good Corrosion-Resistance

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.197-198.1545 ◽

2011 ◽

Vol 197-198 ◽

pp. 1545-1548 ◽

Cited By ~ 1

Author(s):

Qi Bing Chang ◽

Xing Qin Liu ◽

Xia Wang ◽

Yong Qing Wang ◽

Jian Er Zhou

Keyword(s):

Corrosion Resistance ◽

Bending Strength ◽

Sintering Temperature ◽

High Strength ◽

Composite Ceramic ◽

Ceramic Membranes ◽

Porous Ceramics ◽

Sintering Aid ◽

Filtration Membrane ◽

Before And After

In order to develop porous ceramics with high strength and corrosion resistance as the support for the preparation of asymmetric ceramic membranes, porous ZrO2-Al2O3 composite is designed and fabricated by adding Zr(OH)4.as sintering aid. The content of Zr(OH)4, the sintering temperature and the bending strength before and after corrosion of the composite are discussed. The results shows that 10wt% ZrO2-10wt% Zr(OH)4 -80wt%Al2O3 composite bar fabricated by cold press with the porosity of 32% can be fabricated in 1550°C for 4 h. The bending strength of the composite is 111.2MPa. After corrosion, the quality lose and the bending strength lose is no more than 1%. The tubular composite is suit for the preparation of micro-filtration membrane.

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Marine Precursors-Based Biomorphic SiC Ceramics

Materials Science Forum ◽

10.4028/www.scientific.net/msf.587-588.67 ◽

2008 ◽

Vol 587-588 ◽

pp. 67-71 ◽

Cited By ~ 5

Author(s):

Miriam López-Álvarez ◽

Lourdes Rial ◽

Jacinto P. Borrajo ◽

Pio González ◽

Julia Serra ◽

...

Keyword(s):

Silicon Carbide ◽

Base Material ◽

High Strength ◽

Biochemical Properties ◽

Natural Material ◽

Original Material ◽

Saccorhiza Polyschides ◽

Innovative Material ◽

Carbide Ceramics ◽

Silicon Carbide Ceramics

Biomorphic silicon carbide ceramics is very promising as a natural base material for biomedical applications due to their excellent mechanical-biochemical properties and biocompatible behaviour. This innovative material is produced by molten-Si infiltration of carbon templates obtained by controlled pyrolysis of biological precursors. The final product is a light, tough and high-strength material with predictable microstructure. In this study the possibility to produce biomorphic silicon carbide ceramics using marine precursors is demonstrated. Due to the great biodiversity offered by the marine medium, a previous selection of algae (Laminaria ochroleuca Bachelot de la Pylaie, Undaria pinnatifida (Harvey) Suringar, Saccorhiza polyschides (Lightfoot) Batters and Cystoseira baccata (Gmelin) Silva) and marine plants (Zostera marina L. and Juncus maritimus L.) was carried out, taking into account its microstructure, porosity and interconnectivity of each species. The bioceramization process was evaluated in three phases: original material analysis, pyrolysis process and reactive melt Si-infiltration. For each marine precursor, a detailed study by Scanning Electron Microscopy (SEM) of the natural material, the carbon preform and the final SiC biomorphic product is described. The viability to obtain biomorphic SiC ceramic material for all the selected marine precursors is discussed.

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