Silicon Nitride/Boron Nitride Composite by Combustion Synthesis

Machinable silicon nitride/ hexahedral boron nitride (Si3N4/h-BN) composites were in-situ synthesized in a nitrogen (N2) atmosphere by means of combustion synthesis gas-solid reaction with silicon (Si) powder and h-BN as raw materials. The effect of the volume fraction of h-BN on the machinable properties of Si3N4/BN composite was studied. The results show that Si powder was fully nitrified and no residual Si was found. Microstructures by a scanning electron microscopy (SEM) show Columnar crystals of β-Si3N4 are the main phase and acicular crystals of h-BN disperse β-Si3N4 intergranular. With the increasing of the volume content of h-BN, the machinability of the composite increases, but the bending strength of composite decreases firstly and then increases. The lowest bending strength is 84.96MPa at 25% volume fraction of h-BN.

Download Full-text

Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite

Crystals ◽

10.3390/cryst11040422 ◽

2021 ◽

Vol 11 (4) ◽

pp. 422

Author(s):

Kuai Zhang ◽

Yungang Li ◽

Hongyan Yan ◽

Chuang Wang ◽

Hui Li ◽

...

Keyword(s):

Mechanical Properties ◽

Bending Strength ◽

Sintering Temperature ◽

Raw Materials ◽

Hot Press ◽

Microstructure And Mechanical Properties ◽

Powder Particles ◽

Hot Press Sintering ◽

Sintering Method

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.

Download Full-text

In Situ Preparation and Mechanical Properties of (ZrB2+ZrC)/Zr3[Al(Si)]4C6 Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.602-603.438 ◽

2014 ◽

Vol 602-603 ◽

pp. 438-442

Author(s):

Lei Yu ◽

Jian Yang ◽

Tai Qiu

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Bending Strength ◽

Coefficient Of Thermal Expansion ◽

Raw Materials ◽

Linear Increase ◽

Fine Grain ◽

Fine Grain Strengthening ◽

Uniform Microstructure

Fully dense (ZrB2+ZrC)/Zr3[Al (Si)]4C6 composites with ZrB2 content varying from 0 to 15 vol.% and fixed ZrC content of 10 vol.% were successfully prepared by in situ hot-pressing in Ar atmosphere using ZrH2, Al, Si, C and B4C as raw materials. With the increase of ZrB2 content, both the bending strength and fracture toughness of the composites increase and then decrease. The synergistic action of ZrB2 and ZrC as reinforcements shows significant strengthening and toughing effect to the Zr3[Al (Si)]4C6 matrix. The composite with 10 vol.% ZrB2 shows the optimal mechanical properties: 516 MPa for bending strength and 6.52 MPa·m1/2 for fracture toughness. With the increase of ZrB2 content, the Vickers hardness of the composites shows a near-linear increase from 15.3 GPa to 16.7 GPa. The strengthening and toughening effect can be ascribed to the unique mechanical properties of ZrB2 and ZrC reinforcements, the differences in coefficient of thermal expansion and modulus between them and Zr3[Al (Si)]4C6 matrix, fine grain strengthening and uniform microstructure derived by the in situ synthesis reaction.

Download Full-text

In Situ Reaction Synthesis of Silicon Carbide-Boron Nitride Composite from Silicon Nitride-Boron Oxide-Carbon

Journal of the American Ceramic Society ◽

10.1111/j.1151-2916.2002.tb00544.x ◽

2004 ◽

Vol 85 (11) ◽

pp. 2858-2860 ◽

Cited By ~ 12

Author(s):

Guo-Jun Zhang ◽

Yoshihisa Beppu ◽

Motohide Ando ◽

Jian-Feng Yang ◽

Tatsuki Ohji

Keyword(s):

Silicon Carbide ◽

Silicon Nitride ◽

Boron Nitride ◽

Boron Oxide ◽

Reaction Synthesis ◽

In Situ Reaction

Download Full-text

Effect of raw materials on microstructure and bending strength of porous in situ MgO/Fe–Cr–Ni composites

Materials Science and Engineering A ◽

10.1016/j.msea.2011.07.044 ◽

2011 ◽

Vol 528 (29-30) ◽

pp. 8438-8442 ◽

Cited By ~ 3

Author(s):

Chang Chen ◽

Congyang Chu ◽

Jianfeng Yang ◽

Chonggao Bao ◽

Guanjun Qiao ◽

...

Keyword(s):

Bending Strength ◽

Raw Materials

Download Full-text

Multilayer SiC/Si Composites Derived from Papers

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1361 ◽

2007 ◽

Vol 336-338 ◽

pp. 1361-1363 ◽

Cited By ~ 1

Author(s):

Gang Bin Yang ◽

Yin Juan Liu ◽

Guan Jun Qiao ◽

Zhi Hao Jin

Keyword(s):

Raw Materials ◽

Silicon Powder ◽

Thin Layers ◽

Liquid Silicon ◽

Vacuum Furnace ◽

Laminar Structure ◽

In Situ Reaction ◽

N2 Atmosphere ◽

Multilayer Composites

The SiC/Si multilayer composites were fabricated successfully by reaction sintering method with normal stacked papers as the raw materials. Paper was cut into rectangular sheets and stacked, then infiltrated with phenolic resin to get a laminar structure. This paper /resin laminar composite was transformed into porous carbon with laminar structure after heating at 800 oC for 2h in N2 atmosphere. Finally this porous laminar carbon was reheated with silicon powder at 1450-1650oC for 1-2h in a vacuum furnace and SiC/Si multilayer composites can be obtained through the in-situ reaction between carbon and liquid silicon. The microstructure, reaction mechanism, phase composition and mechanical properties of these multilayer composites were researched. The final material shows a distingished laminar structure with alternating arrangement of SiC thick layers and silicon thin layers. SiC layer was composed by beta-SiC and a little of free silicon and carbon not reacted. The capillarity infiltration and in-situ reaction of liquid silicon act key roles in this process. Higher strength and non-catastrophic failure mode for this material were observed.

Download Full-text

Mechanical Properties of Hot-Pressed B4C-TiB2 Composites Synthesized from B4C-TiO2 and B4C-TiC

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.902.81 ◽

2021 ◽

Vol 902 ◽

pp. 81-86

Author(s):

Shu Mao Zhao ◽

Ling Ran Zhao

Keyword(s):

Mechanical Properties ◽

Mechanical Property ◽

Volume Fraction ◽

Raw Materials ◽

Ceramic Composites ◽

In Situ Synthesis ◽

Second Phase ◽

Pressing Method ◽

The One

In this study, B4C-TiB2 ceramic composites were manufactured by hot pressing method. The raw materials for the in-situ synthesis of TiB2 were TiO2 and TiC. After being sintered at 1900°C for 60min under a pressure of 30MPa, compact composites samples with a TiB2 volume fraction range from 0 to 11.05% were prepared. The relative density, fracture toughness and flexural strength of different sample were tested. Microstructures on the fracture surface were studied by SEM. The result shows that B4C-TiB2 ceramic composites sintered from B4C-TiC had a better mechanical property than the one sintered from B4C-TiO2. When the content of TiB2 (reacted from TiC) was 11.05vol.%, the strength and toughness of B4C-TiB2 ceramics can reach 598MPa and 6.45MPa·m1/2. The toughening mechanisms of B4C-TiB2 composites include micro-crack toughening and energy consumption by the pulling out process of second phase.

Download Full-text

Silicon Nitride/Boron Nitride Composite by Combustion Synthesis

Materials Science Forum - PRICM 6 ◽

10.4028/0-87849-462-6.531 ◽

2007 ◽

pp. 531-534

Author(s):

Ke Zhang ◽

Qiang Zhang ◽

Peng Fei Wang ◽

Ling Bai ◽

Wei Ping Shen ◽

...

Keyword(s):

Silicon Nitride ◽

Boron Nitride ◽

Combustion Synthesis

Download Full-text

Study on Hole-Sealing Coating of Porous Silicon Nitride Surface

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.537.20 ◽

2013 ◽

Vol 537 ◽

pp. 20-23

Author(s):

Qi Hong Wei ◽

Chong Hai Wang ◽

Ling Li ◽

Hong Sheng Wang ◽

Jian Liu ◽

...

Keyword(s):

Electron Microscope ◽

Silicon Nitride ◽

Porous Silicon ◽

Water Absorption ◽

Bending Strength ◽

Sol Gel ◽

Universal Testing ◽

Before And After ◽

Scanning Electron ◽

Sealing Coating

Hole-sealing coating was fabricated on the porous silicon nitridesubstrate by sol-gel method, with Li2O-Al2O3-SiO2 as the basic materials and other additives were added. The morphology of the coating was tested by scanning electron microscope(SEM). The density,water absorption and porosity of porous silicon nitride before and after coating were tested by Archimedes method.The bending strength was tested by universal testing machine．The results indicated that the water absorption of porous silicon nitride was decreaced by 93.73% to 96.74%, the bending strength of porous silicon nitride was increaced by 8.21％ to 15.56％.

Download Full-text

In Situ Combustion Synthesis of h-BN-SiC High-Temperature Ceramics

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.353-358.1501 ◽

2007 ◽

Vol 353-358 ◽

pp. 1501-1504 ◽

Cited By ~ 3

Author(s):

Hong Bo Li ◽

Yong Ting Zheng ◽

Jie Cai Han

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Combustion Synthesis ◽

Bending Strength ◽

Silicon Powder ◽

Nitrogen Pressure ◽

In Situ Combustion ◽

Reaction Thermodynamics ◽

Adiabatic Combustion Temperature

The feasibility of fabricating h-BN-SiC high-temperature ceramics by in-situ combustion synthesis was demonstrated by igniting the mixture of boron carbide and silicon powder under 100MPa nitrogen pressure. The reaction thermodynamics and the adiabatic combustion temperature were calculated theoretically. The phase composition, microstructure and mechanical properties of composite were identified by XRD and SEM. The maximum bending strength and fracture toughness of the composite were 65.2 MPa and 1.4 MPa·m1/2 under room temperature, respectively. The effects of h-BN and SiC dilution contents on the mechanical properties of composite were also discussed.

Download Full-text

Effects of Alloys on Microstructure and Properties of Mo2FeB2-Based Cermets

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.399-401.399 ◽

2011 ◽

Vol 399-401 ◽

pp. 399-402 ◽

Cited By ~ 1

Author(s):

Qing Fang Wang ◽

Ying Jun Pan ◽

Bing Hu ◽

Lei Zhou

Keyword(s):

Bending Strength ◽

Raw Materials ◽

High Hardness ◽

Liquid Phase Sintering ◽

Hard Phase ◽

Microstructure And Properties ◽

Fine Grain ◽

Mechanics Performance ◽

Different Content

Mo2FeB2cermets were prepared by in-situ reaction and vacuum liquid phase sintering technology which used Mo powder, Fe powder and FeB powder as raw materials. Added with the different content of Cr, Ni, the influence on microstructure and properties of the alloy were studied, and the distribution and phase of the alloy was investigated by SEM, EDS, XRD. The results show that Ni only exists in the binder of the cermets, Cr exists in both hard phase and binder and produces the particles of Mo2FeB2fine grain size, With 10%wt of Cr, 2%wt of Ni added, comprehensive mechanics performance of the material is best and the bending strength was highest with high hardness.

Download Full-text