Phase transformation and grain growth in silicon carbide powders

Coppi, P.A. Kistler-De; Richarz, Werner

doi:10.1016/0267-3762(86)90012-3

Cited by 28 publications

(17 citation statements)

References 3 publications

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“…Silicon carbide crystallises in numerous polytypes which differ from their stacking sequence of tetrahedron CSi 4 and SiC 4 in the [0 0 0 1] direction. 1 The most common polytypes are (i) the cubic, 3C, crystal structure designed as ␤-SiC and (ii) hexagonal or rhombohedral crystal structures (2H, 4H, 6H and 15R) collectively designed as ␣-SiC.…”

Section: Introductionmentioning

confidence: 99%

Pressureless sintered silicon carbide tailored with aluminium nitride sintering agent

Malinge

Coupé

Jouannigot

et al. 2012

Journal of the European Ceramic Society

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Section: Introductionmentioning

confidence: 99%

Pressureless sintered silicon carbide tailored with aluminium nitride sintering agent

Malinge

Coupé

Jouannigot

et al. 2012

Journal of the European Ceramic Society

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“…Beta silicon carbide (B-SiC) can be formed at temperatures as low as 798 K (525°C) (Baumann, 1952 the reaction takes place at temperatures above 1800K (1527°C) (Poch and Dietzel, 1962). The transformation of relatively pure j1-SiC to the alpha crystalline form (a-SiC), specifically the 6H crystalline polytype, occurs at temperatures above 2173 K (1900 0c) (Kistler-De Coppi and Richarz, 1986). Further crystal growth occurs by a vapor transport mechanism; the activation energy is similar to the value for the heat of sublimation of solid SiC.…”

Section: Basic Silicon Carbide Process Descriptionmentioning

confidence: 97%

“…Aluminum tends to stabilize the hexagonal modifications, particularly the 4H structure (Shinozaki et al, 1988), while boron stabilizes the 6H form (Kistler-De Coppi and Richarz, 1986). Particularly since, coincident with these phase changes, exaggerated grain growth is often observed.…”

Section: Effect Of Impuritiesmentioning

confidence: 99%

“…Silicon carbide totally decomposes to graphite and Si at 3103 K (2830°C) (Scace and Slack, 1960). The maximum solubility of Al is 2.0% (Kistler-De Coppi and Richarz, 1986). However, such pure SiC cannot be made on a commercial scale because nitrogen from air is soluble in SiC, causing the crystals to take on a green color.…”

Section: Basic Silicon Carbide Process Descriptionmentioning

confidence: 99%

“…Additions of Al and B affect the crystal growth rate and the dominant crystal structure that is produced (Kistler-De Coppi and Richarz, 1986). Pure SiC that has been heated above 2373 K (2100°C) has a 6H structure, shown in practice by the presence of well formed hexagonal-shaped platelets.…”

Section: Basic Silicon Carbide Process Descriptionmentioning

confidence: 99%

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Carbide, Nitride and Boride Materials Synthesis and Processing

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Silicon Carbide

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Chia²,

Kunz³

et al. 2000

Kirk-Othmer Encyclopedia of Chemical Technology

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Silicon carbide, SiC, is a crystalline material having a color that varies from nearly clear through pale yellow or green to black, depending on the amount of impurities. It occurs naturally only as the mineral moissanite in the meteorite iron of Canon Diablo, Arizona. The commercial product, which is made in an electric furnace, is usually obtained as an aggregate of iridescent crystals. The iridescence is caused by a thin layer of silica produced by superficial oxidation of the carbide. The loose black or green grain of commerce is prepared from the manufactured product by crushing and grading for size. Traditionally, the metallurgical, abrasive, and refractory industries are the largest users of silicon carbide. SiC is also used for heating elements in electric furnaces, in electronic devices, and in applications where its resistance to nuclear radiation damage is advantageous. The development of advanced pressureless sintering and complex shape‐forming technologies has led to silicon carbide becoming one of the most important structural ceramics. Silicon carbide has found wide acceptance in wear‐, erosion‐, and corrosion‐resistant applications; it has demonstrated excellent performance as a heat‐exchanger material; it is also being evaluated for prototype high temperature gas turbine engine component applications. The measurements made on commercial, polycrystalline products should not be interpreted as being representative of single‐crystal silicon carbide. The pressureless‐sintered silicon carbides, being essentially single‐phase, fine‐grained, and polycrystalline, have properties distinct from both single crystals and direct‐bonded silicon carbide refractories. Silicon carbide may crystallize in the cubic, hexagonal, or rhombohedral structure. Silicon carbide is a leading candidate material for rotating and static components in many gas turbine engine applications. As is the case for other ceramics, silicon carbide is brittle in nature. The strength of a silicon carbide component is determined by preexisting flaws introduced into the material during processing. Sintered silicon carbide retains its strength at elevated temperatures. Silicon carbide is a semiconductor: it has a conductivity between that of metals and insulators or dielectrics. Silicon carbide is comparatively stable. The only violent reaction occurs when SiC is heated with a mixture of potassium dichromate and lead chromate. There are several routes to preparing SiC powders. Methods that have been examined include growth by sublimation from the vapor phase, carbothermic reduction, and crystallization from a melt. The high modulus, high intrinsic strength, and temperature stability make SiC, in the form of whiskers, platelets, and fibers, a promising candidate reinforcement material for metal, polymer, and ceramic matrix composites. Silicon carbide has been described as a mild inhalation irritant. The threshold limit value for silicon carbide in the atmosphere is 5 mg/m 3 .

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Phase transformation and grain growth in silicon carbide powders

Cited by 28 publications

References 3 publications

Pressureless sintered silicon carbide tailored with aluminium nitride sintering agent

Pressureless sintered silicon carbide tailored with aluminium nitride sintering agent

Carbide, Nitride and Boride Materials Synthesis and Processing

Silicon Carbide

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