Opportunities for Enhancing the Thermal Conductivities of SiC and Si3N4 Ceramics Through Improved Processing

Haggerty, J. S.; Lightfoot, A.

doi:10.1002/9780470314715.ch52

Cited by 115 publications

(66 citation statements)

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“…However, intrinsically, an ideal Si 3 N 4 crystal should have high thermal conductivity. In 1995, Haggerty and Lightfoot pointed out that the intrinsic thermal conductivity of Si 3 N 4 might be over 200 W/m/K at room temperature 3 . Later, using a molecular dynamics method, Hirosaki et al 2 estimated that the thermal conductivities of an ideal β‐Si 3 N 4 single crystal, along the a and c directions, are 170 and 450 W/m/K at a temperature of 300 K, respectively 4 .…”

Section: Introductionmentioning

confidence: 99%

Sintered Reaction‐Bonded Silicon Nitride with High Thermal Conductivity and High Strength

Zhou

Zhu

Hirao

et al. 2008

Int J Applied Ceramic Tech

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Sintered reaction‐bonded silicon nitride (SRBSN) materials were prepared from a high‐purity Si powder doped with Y2O3 and MgO as sintering additives by nitriding at 1400°C for 8 h and subsequently postsintering at 1900°C for various times ranging from 3 to 24 h. Microstructures and phase compositions of the nitrided and the sintered compacts were characterized. The SRBSN materials sintered for 3, 6, 12, and 24 h had thermal conductivities of 100, 105, 117, and 133 W/m/K, and four‐point bending strengths of 843, 736, 612, and 516 MPa, respectively. Simultaneously attaining thermal conductivity and bending strength at such a high level made the SRBSN materials superior over the high‐thermal conductivity silicon nitride ceramics that were prepared by sintering of Si3N4 powder in our previous works. This study indicates that the SRBSN route is a promising way of fabricating silicon nitride materials with both high thermal conductivity and high strength.

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Section: Introductionmentioning

confidence: 99%

Sintered Reaction‐Bonded Silicon Nitride with High Thermal Conductivity and High Strength

Zhou

Zhu

Hirao

et al. 2008

Int J Applied Ceramic Tech

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“…Duophase (α +β )-sialons have thermal conductivities intermediate to those of α -sialon and β -sialon, with thermal conductivity increasing with β -phase content [78]. β -Si 3 N 4 has high intrinsic thermal conductivity [177,178,[187][188][189][190], with reported thermal conductivities for β -Si 3 N 4 as high as 162 W.m -1 .K -1 [191]. The intrinsic thermal conductivity of α-Si 3 N 4 is lower than that of β -Si 3 N 4 , due to the higher complexity of its crystal structure [189], with thermal conductivity of silicon nitride ceramics increasing with increasing β -phase content [91,192].…”

Section: Thermal Conductivitymentioning

confidence: 99%

A review of the processing, composition, and temperature-dependent mechanical and thermal properties of dielectric technical ceramics

et al. 2011

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The current review uses the material requirements of a new space propulsion device, the Variable Specific Impulse Magnetoplasma Rocket (VASIMR ® ) as a basis for presenting the temperature dependent properties of a range of dielectric ceramics, but data presented could be used in the engineering design of any ceramic component with complementary material requirements. A material is required for the gas containment tube (GCT) of VASIMR ® to allow it to operate at higher power levels. The GCT's operating conditions place severe constraints on the choice of material. A dielectric is required with a high thermal conductivity, low dielectric loss factor, and high thermal shock resistance. There is a lack of a representative set of temperature-dependent material property data for materials considered for this application and these are required for accurate thermo-structural modelling. This modelling would facilitate the selection of an optimum material for this component. The goal of this paper is to determine the best material property data values for use in the materials selection and design of such components. A review of both experimentally and theoretically-determined temperature-dependent & room temperature properties of several materials has been undertaken. Data extracted are presented by property. Properties reviewed are density, Young's, bulk and shear moduli, Poisson's ratio, tensile, flexural and compressive strength, thermal conductivity, specific heat capacity, thermal expansion coefficient and the factors affecting maximum service temperature. Materials reviewed are alumina, aluminium nitride, beryllia, fused quartz, sialon and silicon nitride.

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“…During sintering, the doped Al 2 O 3 dissolved into the lattice of β‐Si 3 N 4 to form β‐SiAlON solid solution, which could greatly reduce the thermal conductivity of the sintered Si 3 N 4 by causing phonon‐scattering . For this reason, Si 3 N 4 was not regarded as a high‐thermal‐conductivity material until Haggerty et al . pointed out that the intrinsic thermal conductivity of Si 3 N 4 might be over 200 W/m/K at room temperature in 1995.…”

Section: Introductionmentioning

confidence: 99%

Fracture Resistance Behavior of High‐Thermal‐Conductivity Silicon Nitride Ceramics

Zhou

Ohji

Hyuga

et al. 2013

Int J Applied Ceramic Tech

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Silicon nitride ceramics were prepared from a high‐purity silicon powder doped with 2 mol% Y2O3 and 5 mol% MgO as sintering additives via a route of sintering of reaction‐bonded silicon nitride (SRBSN). The materials sintered at 1900°C for 3, 6, 12, and 24 h had thermal conductivities of 109, 125, 146, and 154 W/m/K, and four‐point bending strengths of 786, 676, 608, and 505 MPa, respectively. The fracture toughness values, determined by the single‐edge‐precracked‐beam (SEPB) method, were 8.4, 8.6, 9.7, and 10.7 MPa m1/2 for the materials sintered for 3, 6, 12, and 24 h, respectively, which were similar to the results measured by the chevron‐notched‐beam (CNB) test method. The materials sintered for longer times (12 and 24 h) showed stronger R‐curve behaviors over longer range of crack extension, in comparison with the materials sintered for shorter times (3 and 6 h).

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Opportunities for Enhancing the Thermal Conductivities of SiC and Si3N4 Ceramics Through Improved Processing

Cited by 115 publications

References 0 publications

Sintered Reaction‐Bonded Silicon Nitride with High Thermal Conductivity and High Strength

Sintered Reaction‐Bonded Silicon Nitride with High Thermal Conductivity and High Strength

A review of the processing, composition, and temperature-dependent mechanical and thermal properties of dielectric technical ceramics

Fracture Resistance Behavior of High‐Thermal‐Conductivity Silicon Nitride Ceramics

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