• Title/Summary/Keyword: Reaction-bonded silicon carbide

Search Result 33, Processing Time 0.028 seconds

Silicon Melt Infiltration of Reaction-Bonded Silicon Carbide (반응소결 탄화규소에서 실리콘의 침윤향상)

  • 신현익;김주선;이종호;김긍호;송휴섭;이해원
    • Journal of the Korean Ceramic Society
    • /
    • v.39 no.7
    • /
    • pp.693-698
    • /
    • 2002
  • Reaction-Bonded Silicon Carbide (RBSC) Ceramics were fabricated which satisfies the maximum packing density of silicon carbide skeleton in the green compacts. Such a high packing density induced incomplete infiltration during reaction-sintering; forms linear void around the interface of large alpha silicon carbide powders. During reaction-sintering, the limited extraction and entrapped gas induced by residue oxide was considered to be a reason of linear void formation. In order to improve infiltration behavior in the highly packed preform, the pre-treatment methods for residue oxide removal were proposed.

Properties of Silicon Carbide-Carbon Fiber Composites Prepared by Infiltrating Porous Carbon Fiber Composites with Liquid Silicon

  • Lee, Jae-Chun;Park, Min-Jin;Shin, Kyung-Sook;Lee, Jun-Seok;Kim, Byung-Gyun
    • The Korean Journal of Ceramics
    • /
    • v.3 no.4
    • /
    • pp.229-234
    • /
    • 1997
  • Silicon carbide-carbon fiber composites have been prepared by partially Infiltrating porous carbon fiber composites with liquid silicon at a reaction temperature of $1670^{\circ}C$. Reaction between molten silicon and the fiber preform yielded silicon carbide-carbon fiber composites composed of aggregates of loosely bonded SiC crystallites of about 10$\mu\textrm{m}$ in size and preserved the appearance of a fiber. In addition, the SiC/C fiber composites had carbon fibers coated with a dense layer consisted of SiC particles of sizes smaller than 1$\mu\textrm{m}$. The physical and mechanical properties of SiC/C fiber composites were discussed in terms of infiltrated pore volume fraction of carbon preform occupied by liquid silicon at the beginning of reaction. Lower bending strength of the SiC/C fiber composites which had a heterogeneous structure in nature, was attributed to the disruption of geometric configuration of the original carbon fiber preform and the formation of the fibrous aggregates of the loosely bonded coarse SiC particles produced by solution-precipitation mechanism.

  • PDF

Fabrication of Porous Reaction Bonded Silicon Carbide with Multi-Layered Pore Structures (다층 기공구조를 갖는 다공성 반응소결 탄화규소 다공체 제조)

  • Cho, Gyoung-Sun;Kim, Gyu-Mi;Park, Sang-Whan
    • Journal of the Korean Ceramic Society
    • /
    • v.46 no.5
    • /
    • pp.534-539
    • /
    • 2009
  • Reaction Bonded Silicon Carbide(RBSC) has been used for engineering ceramics due to low-temperature fabrication and near-net shape products with excellent structural properties such as thermal shock resistance, corrosion resistance and mechanical strength. Recently, attempts have been made to develop hot gas filter with gradient pore structure by RBSC to overcome weakness of commercial clay-bonded SiC filter such as low fracture toughness and low reliability. In this study a fabrication process of porous RBSC with multi-layer pore structure with gradient pore size was developed. The support layer of the RBSC with multi-layer pore structure was fabricated by conventional Si infiltration process. The intermediate and filter layers consisted of phenolic resin and fine SiC powder were prepared by dip-coating of the support RBSC in slurry of SiC and phenol resin. The temperature of $1550^{\circ}C$ to make Si left in RBSC support layer infiltrate into dip-coated layer to produce SiC by reacting with pyro-carbon from phenol resin.

Effect of the SiC Size on the Thermal and Mechanical Properties of Reaction-bonded Silicon Carbide Ceramics (반응소결 탄화규소 세라믹스의 열물성과 기계적 특성에 미치는 SiC 크기의 영향)

  • Kwon, Chang-Sup;Oh, Yoon-Suk;Lee, Sung-Min;Han, Yoonsoo;Shin, Hyun-Ick;Kim, Youngseok;Kim, Seongwon
    • Journal of Powder Materials
    • /
    • v.21 no.6
    • /
    • pp.467-472
    • /
    • 2014
  • RBSC (reaction-bonded silicon carbide) represents a family of composite ceramics processed by infiltrating with molten silicon into a skeleton of SiC particles and carbon in order to fabricate a fully dense body of silicon carbide. RBSC has been commercially used and widely studied for many years, because of its advantages, such as relatively low temperature for fabrication and easier to form components with near-net-shape and high relative density, compared with other sintering methods. In this study, RBSC was fabricated with different size of SiC in the raw material. Microstructure, thermal and mechanical properties were characterized with the reaction-sintered samples in order to examine the effect of SiC size on the thermal and mechanical properties of RBSC ceramics. Especially, phase volume fraction of each component phase, such as Si, SiC, and C, was evaluated by using an image analyzer. The relationship between microstructures and physical properties was also discussed.

Fabrication of Carbon Fiber Reinforced Reaction Bonded SiC Composite Fabricated by a Molten Si Infiltration Method; I. The Effect of Carbon Fiber Coating Process (용융 Si 침윤법에 의해 제조된 반응소결 탄소 섬유강화 탄화규소 복합체 제조; I. 탄소 섬유 코팅 방법에 따른 영향)

  • Yun, Sung-Ho;Tan, Phung Nhut;Cho, Gyung-Sun;Cheong, Hun;Kim, Young-Do;Park, Sang-Whang
    • Journal of the Korean Ceramic Society
    • /
    • v.45 no.9
    • /
    • pp.531-536
    • /
    • 2008
  • Reaction bonded silicon carbide (RBSC) composite for heat-exchanger was fabricated by molten Si infiltration method. For enforcing fracture toughness to reaction bonded silicon carbide composite, the surface of carbon fiber has coating layer by SiC or pyro-carbon. For SiC layer coating, CVD method was used. And for carbon layer coating, the phenol resin was used. In the case of carbon layer coating, fracture toughness and fracture strength were enhancing to 4.4 $MPa{\cdot}m^{1/2}$ and 279 MPa.

Effect of Green Microstructure on Sintered Microstructure and Mechanical Properties of Reaction-Bonded Silicon Carbide (성형미세구조가 반응소결 탄화규소체의 소결미세구조 및 기계적 특성에 미치는 영향)

  • 박현철;김재원;백운규;최성철
    • Journal of the Korean Ceramic Society
    • /
    • v.36 no.1
    • /
    • pp.97-105
    • /
    • 1999
  • In the binary system of SiC and carbon, porosity and pore size distribution of green body was controlled by varying pH, by the addition of polyelectrolyte dispersants, and by using different particle size of starting powders. The preforms having different green microstructure were fabricated by slip casting from suspensions having different dispersion condition. The reaction bonding process was carried out for these preforms. The condition of reaction bonding was 1600$^{\circ}C$ and 20 min. under vacuum atmosphere. The analyses of optical and SEM were studied to investigate the effect of green microstructure on that of reaction bonded silicon carbide and subsequently the mechanical properties of sintered body was investigated. Different green microstructures were obtained from suspensions having different dispersion condition. It was found that the pore size could be remarkably reduced for a fine SiC(0.5$\mu\textrm{m}$). The bimodal microstructure was not found in the present study, which is frequently observed in the typical reaction bonded silicon carbide. It is considered that the ratio between SiC and C was responsible for the formation of bimodal microstructure. For the preform fabricated from the well dispersed suspension, the 3-point bending strength of reaction-bonded silicon carbide was 310${\pm}$40 MPa compared to the specimen fabricated from relatively agglomerated particles having lower value 260${\pm}$MPa.

  • PDF

Effects of Mixing Ratio of Silicon Carbide Particles on the Etch Characteristics of Reaction-Bonded Silicon Carbide

  • Jung, Youn-Woong;Im, Hangjoon;Kim, Young-Ju;Park, Young-Sik;Song, Jun-Baek;Lee, Ju-Ho
    • Journal of the Korean Ceramic Society
    • /
    • v.53 no.3
    • /
    • pp.349-353
    • /
    • 2016
  • We prepared a number of reaction-bonded silicon carbides (RBSCs) made from various mixing ratios of raw SiC particles, and investigated their microstructure and etch characteristics by Reactive Ion Etch (RIE). Increasing the amount of $9.5{\mu}m$-SiC particles results in a microstructure with relatively coarser Si regions. On the other hand, increasing that of $2.6{\mu}m$-SiC particles produces much finer Si regions. The addition of more than 50 wt% of $2.6{\mu}m$-SiC particles, however, causes the microstructure to become partially coarse. We also evaluated their etching behaviors in terms of surface roughness (Ra), density and weight changes, and microstructure development by employing Confocal Laser Scanning Microscope (CLSM) and Scanning Electron Microscope (SEM) techniques. During the etching process of the prepared samples, we confirmed that the residual Si region was rapidly removed and formed pits isolating SiC particles as islands. This leads to more intensified ion field on the SiC islands, and causes physical corrosion on them. Increased addition of $2.6{\mu}m$-SiC particles produces finer residual Si region, and thus decreases the surface roughness (Ra.) as well as causing weight loss after etching process by following the above etching mechanism.

Mechanical Strength Values of Reaction-Bonded-Silicon-Carbide Tubes with Different Sample Size (튜브형상 반응소결 탄화규소 부품의 시편크기에 따른 강도평가 유용성 고찰)

  • Kim, Seongwon;Lee, Soyul;Oh, Yoon-Suk;Lee, Sung-Min;Han, Yoonsoo;Shin, Hyun-Ick;Kim, Youngseok
    • Journal of Powder Materials
    • /
    • v.24 no.6
    • /
    • pp.450-456
    • /
    • 2017
  • Reaction-bonded silicon carbide (RBSC) is a SiC-based composite ceramic fabricated by the infiltration of molten silicon into a skeleton of SiC particles and carbon, in order to manufacture a ceramic body with full density. RBSC has been widely used and studied for many years in the SiC field, because of its relatively low processing temperature for fabrication, easy use in forming components with a near-net shape, and high density, compared with other sintering methods for SiC. A radiant tube is one of the most commonly employed ceramics components when using RBSC materials in industrial fields. In this study, the mechanical strengths of commercial RBSC tubes with different sizes are evaluated using 3-point flexural and C-ring tests. The size scaling law is applied to the obtained mechanical strength values for specimens with different sizes. The discrepancy between the flexural and C-ring strengths is also discussed.