Elimination of grain boundaries and its effect on the properties of silicon nitride ceramics

Hu, Feng; Zhu, Tianbin; Xie, Zhihui; Liu, Jian; Hu, Zunlan; An, Di

doi:10.1016/j.ceramint.2020.02.024

Cited by 20 publications

(7 citation statements)

References 24 publications

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“…Three main factors in uence the thermal conductivity of Si 3 N 4 ceramics. Firstly, the thermal conductivity of the secondary phase is generally low, only 1-10 W•m − 1 •k − 1 , and the presence of a large amount of the secondary phase often has harmful effect on the thermal conductivity of Si 3 N 4 ceramic [11,15,29,43].…”

Section: Resultsmentioning

confidence: 99%

“…Although Hirosaki et al [7] reported that the theoretical thermal conductivity of β-Si 3 N 4 along the a and c axes was 170 W•m − 1 •k − 1 and 450 W•m − 1 •k − 1 . However, metallic impurity [8,9], secondary phases [10][11][12] and lattice defects [13][14][15][16] have effects on thermal conductivity in polycrystalline Si 3 N 4 . The thermal conductivity of commercial Si 3 N 4 ceramic substrate is less than 90 W•m − 1 •k − 1 .…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, these pressure-assisted methods offer very limited product geometry and the cost for processing scales up rapidly with product dimension. Gas pressure sintering is an effective solution to produce parts with complex shapes and isotropic properties [11,12,[41][42][43], with the help of N 2 pressure of 1-10 MPa. Therefore, this method takes its advantages for widely fabricating Si 3 N 4 ceramic substrates.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thermal Conductivity of Si₃N₄ Ceramics Fabricated From Carbothermal-reduction-derived Powder

Wang¹,

Li²,

Wu³

et al. 2021

Preprint

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Si3N4-based ceramic (Si3N4-5wt%Y2O3-3wt%MgO) was obtained from carbothermal-reduction-derived powder combined with gas pressure sintering. The phase, microstructure, thermal conductivity and mechanical properties of Si3N4 ceramics were comprehensively analyzed. Dense Si3N4 ceramic with uniform grain size was obtained after sintering at 1900°C for 7 h under a N2 pressure of 1.2 MPa. The secondary phase consisted of Y4Si2O7N2 and Y2Si3O3N4 was found to gather around triangular grain boundaries. The thermal conductivity, flexural strength, hardness and fracture toughness of the Si3N4 ceramics were 95.7 W·m-1·k-1, 715 MPa, 17.2 GPa and 7.2 MPa·m1/2, respectively. The results were compared with product derived from commercial powder, the improvement of thermal conductivity (~8.3%) and fracture toughness (~4.3%) demonstrating the superiority of Si3N4 ceramics prepared from carbothermal-reduction-derived powder.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermal Conductivity of Si₃N₄ Ceramics Fabricated From Carbothermal-reduction-derived Powder

Wang¹,

Li²,

Wu³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…These advantageous mechanical and physical properties make them highly applicable to various high-tech industries, including medical technology, semiconductor, mechanical engineering, aerospace, automotive, ballistic armor, electronic, and cutting tools [ 8 , 9 , 10 ]. The most broadly used ceramics include zirconia (ZrO 2 ), alumina (Al 2 O 3 ), silicon carbide (SiC), and silicon nitride (Si 3 N 4 ) [ 11 , 12 , 13 , 14 , 15 ]. Their mechanical properties are superior to those of metal materials and polymers.…”

Section: Introductionmentioning

confidence: 99%

A Review on Surface Finishing Techniques for Difficult-to-Machine Ceramics by Non-Conventional Finishing Processes

et al. 2022

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Ceramics are advanced engineering materials in which have been broadly used in numerous industries due to their superior mechanical and physical properties. For application, the industries require that the ceramic products have high-quality surface finishes, high dimensional accuracy, and clean surfaces to prevent and minimize thermal contact, adhesion, friction, and wear. Ceramics have been classified as difficult-to-machine materials owing to their high hardness, and brittleness. Thus, it is extremely difficult to process them with conventional finishing processes. In this review, trends in the development of non-conventional finishing processes for the surface finishing of difficult-to-machine ceramics are discussed and compared to better comprehend the key finishing capabilities and limitations of each process on improvements in terms of surface roughness. In addition, the future direction of non-conventional finishing processes is introduced. This review will be helpful to many researchers and academicians for carrying out additional research related to the surface finishing techniques of ceramics for applications in various fields.

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“…Numerous kinds of research have shown that increasing densification was crucial to improving both the thermal and mechanical properties of Si 3 N 4 ceramics [ 9 , 10 ]. Moreover, large grains can improve the heat transmission efficiency, and the low content of inter-granular secondary phase and lattice defects can reduce phonon scattering to improve thermal conductivity [ 11 , 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Ultra-High Pressure Sintering and Spark Plasma Sintering and Subsequent Heat Treatment on the Properties of Si3N4 Ceramics

Huang

et al. 2022

Materials

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In this study, coarse Beta silicon nitride (β-Si3N4) powder was used as the raw material to fabricate dense Si3N4 ceramics using two different methods of ultra-high pressure sintering and spark plasma sintering at 1550 °C, followed by heat treatment at 1750 °C. The densification, microstructure, mechanical properties, and thermal conductivity of samples were investigated comparatively. The results indicate that spark plasma sintering can fabricate dense Si3N4 ceramics with a relative density of 99.2% in a shorter time and promote α-to-β phase transition. Coarse β-Si3N4 grains were partially fragmented during ultra-high pressure sintering under high pressure of 5 GPa, thereby reducing the number of the nucleus, which is conducive to the growth of elongated grains. The UHP sample with no fine α-Si3N4 powder addition achieved the highest fracture strength (822 MPa) and fracture toughness (6.6 MPa·m1/2). The addition of partial fine α-Si3N4 powder facilitated the densification of the SPS samples and promoted the growth of elongated grains. The β-Si3N4 ceramics SPS sintered with fine α-Si3N4 powder addition obtained the best comprehensive performance, including the highest density of 99.8%, hardness of 1890 HV, fracture strength of 817 MPa, fracture toughness of 6.2 MPa·m1/2, and thermal conductivity of 71 W·m−1·K−1.

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Elimination of grain boundaries and its effect on the properties of silicon nitride ceramics

Cited by 20 publications

References 24 publications

Thermal Conductivity of Si₃N₄ Ceramics Fabricated From Carbothermal-reduction-derived Powder

Thermal Conductivity of Si₃N₄ Ceramics Fabricated From Carbothermal-reduction-derived Powder

A Review on Surface Finishing Techniques for Difficult-to-Machine Ceramics by Non-Conventional Finishing Processes

Effect of Ultra-High Pressure Sintering and Spark Plasma Sintering and Subsequent Heat Treatment on the Properties of Si3N4 Ceramics

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