Sintering of B4C-SiC Composites with ALN-Y2O3 Addition

2012 ◽  
Vol 727-728 ◽  
pp. 850-855
Author(s):  
Rosa Maria da Rocha ◽  
Francisco Cristóvão Lourenço de Melo
Keyword(s):  
Applied Pressure ◽  
Ceramic Composites ◽  
Argon Atmosphere ◽  
Pressureless Sintering ◽  
Sintering Aid ◽  
Suitable Material ◽  
Sic Ceramics ◽  
Sic Ceramic ◽  
Sic Composites ◽  
C 30

One suitable material candidate to improve B4C mechanical properties is SiC. B4C-SiC ceramic composites are very promising armor materials because B4C and SiC are intrinsically very hard. In this work a pressureless sintering study of B4C-SiC ceramics was made. B4C-SiC mixtures were prepared with SiC concentration from 10 to 50 wt%. Without the external applied pressure during sintering it was necessary to add sintering aid. The additive system AlN-Y2O3 was investigated as sintering aid. Samples were densified by pressureless sintering at 2000 °C/30 min in an argon atmosphere. B4C-SiC composites were analyzed by XRD and SEM. Bulk density and total weight loss were also measured. Density higher than 93 % of the theoretical value was determined and microhardness of 30.3 GPa was achieved for composite with 10 wt% of SiC sintered with AlN-Y2O3 additive.

Preparation and Flame Ablation/Oxidation Behavior of ZrB2/SiC Ultra-High Temperature Ceramic Composites

2007 ◽  
Vol 351 ◽  
pp. 142-146 ◽  
Author(s):  
Chang An Wang ◽  
Hai Long Wang ◽  
Yong Huang ◽  
Dai Ning Fang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Thermal Ablation ◽  
Oxidation Behavior ◽  
Ceramic Composites ◽  
Argon Atmosphere ◽  
Good Resistance ◽  
Sic Ceramic ◽  
Sic Whiskers ◽  
Sic Composites

ZrB2/SiC ceramic composites reinforced by nano-SiC whiskers and SiC particles have been prepared by hot-pressing at 1950°C for 1hr under 20 MPa pressure in flow argon atmosphere. Effects of SiC addition on microstructure, mechanical properties and thermal ablation/oxidation behavior of ZrB2/SiC composites were investigated. The results showed that the addition of SiC effectively improved the densification of ZrB2/SiC composites and almost full dense ZrB2/SiC composites were obtained when the amount of SiC increased up to 20 vol%. Flexural strength and fracture toughness of the ZrB2/SiC composites were also enhanced; the maximum strength and toughness reached 600 MPa and 8.81 MPa·m1/2 at SiC additions of 20 vol % and 30 vol%, respectively. The composites possessed good resistance to flame ablation and could keep the whole shape without distinct peeling or cracking after flame ablation by oxyacetylene flame for 3 mins. The more SiC added, the better resistance to flame ablation the composites displayed.

Pressureless Sintering of ZrB2-SiC Ceramics Incorporating Sol-Gel Synthesized Ultra-Fine Ceramic Powders

2010 ◽  
Vol 434-435 ◽  
pp. 193-196 ◽  
Author(s):  
Hui Zhang ◽  
Yong Jie Yan ◽  
Zheng Ren Huang ◽  
Xue Jian Liu ◽  
Dong Liang Jiang
Keyword(s):  
Sol Gel ◽  
Average Particle Size ◽  
Ceramic Composites ◽  
Full Density ◽  
Average Particle ◽  
Pressureless Sintering ◽  
Composite Powders ◽  
Sintering Aid ◽  
Sic Ceramics ◽  
Intermediate Phases

Ultra-high temperature ceramic composites of ZrB2-SiC were densified by pressureless sintering. Ultra-fine ZrB2-SiC composite powders synthesized by sol-gel method were mixed with commercial ZrB2 and SiC powders. The sintered body of hybrid powders (combined commercial and synthesized composite powders) showed excellent properties not only in the relative density but also the flexure strength. Dry-pressed compacts using 4wt% Mo as a sintering aid were sintered to nearly full density at 2200°C/2h. The average strength was ~560MPa and the maximum was ~632MPa. SEM and TEM showed that SiC particles were distributed homogenously in the ZrB2 matrix and the average particle size was ~5μm. From HRTEM observations, the grain boundaries were apparently free of glassy phases and no intermediate phases existed.

scholarly journals Microstructure and mechanical properties of ZrB2-SiC composites fabricated by the centrifugal gel casting

2020 ◽  
Author(s):  
Jingmao Chen ◽  
Dongyang Zhang ◽  
Ping Hu ◽  
Shun Dong ◽  
Xinghong Zhang
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Ph Value ◽  
Ceramic Composites ◽  
Solid Loading ◽  
Pressureless Sintering ◽  
Gel Casting ◽  
Sic Ceramic ◽  
Monomer Content ◽  
Sic Composites

Abstract The high-performance and reliable ZrB2-SiC composites were fabricated by centrifugal gel casting and pressureless sintering. A well-dispersed ZrB2-SiC suspensions with up to 48 vol.% solid loading was achieved by adding 0.6 wt.% PAA dispersant and adjusting pH value to 11. The crack-free green ZrB2-SiC ceramic bodies with homogenous microstructure were prepared successfully by centrifugal gel casting with a relatively low monomer content of 3.5wt.% and centrifugal speed of 9000 r/min. After pressureless sintering at 2000 °C for 1 h, ZrB2-SiC composites with a relative density of 94.8%, a flexural strength of 394 ± 14 MPa and fracture toughness of 4.03 ± 0.10 MPa·m1/2 were achieved. This approach provided a promising colloidal processing to fabricate ceramic composites with reliable properties.

Microstructure and Mechanical Properties of Hot-Pressed and Pressureless Sintered WC-Al2O3 Ceramic Composites

1993 ◽  
Vol 327 ◽  
Author(s):  
Hidehiro Endo ◽  
Masanori Ueki
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Composite System ◽  
Ceramic Composites ◽  
Pressureless Sintering ◽  
Sintering Aid ◽  
Al2o3 Ceramic ◽  
Remarkable Improvement

AbstractFully densified WC-A12O3 composites were successfully consolidated by both hot-pressing and pressureless sintering. The optimum hot-pressing condition for the composites was 1700°C for 2h under a pressure of 40MPa. A remarkable improvement in mechanical properties was achieved in the composite system, especially in WC-30 and -70vol%A12O3, compared to the monolithic WC and A12O3 ceramics. The addition of MgO as a sintering aid had a great effect on the properties of the composites. WC-30vol%A12O3 composite with 1.Owt% MgO addition exhibited flexural strength higher than 1000MPa up to 1200°C, fracture toughness; KIC≥7MPa√m, and hardness; HV ≥2450. In pressureless sintering with the addition of MgO as a sintering aid and subsequent HIP treatment, the WC-30vol%A12O3 composite exhibited the flexural strength higher than 900MPa up to 1200°C.

scholarly journals Effect of Different Sintering Additives on the Microstructure, Phase Compositions and Mechanical Properties of Si3N4/SiC Ceramics

2020 ◽  
Author(s):  
Ying Qin ◽  
Hailing Yang ◽  
Qinggang Li ◽  
Zhi Wang ◽  
Hao Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Glass Phase ◽  
Secondary Recrystallization ◽  
Pressureless Sintering ◽  
Composite Ceramics ◽  
Flexure Strength ◽  
Sic Ceramics ◽  
Liquid Phases ◽  
Sic Ceramic

Abstract Y2O3 and CeO2 were chosen as additives to investigate the effect of different additives on the microstructure, composition of phases and mechanical properties of Si3N4/SiC ceramics using pressureless sintering. Si3N4/SiC ceramic without additives had a high density, while after adding Y2O3 and CeO2, the density and flexural strength of Si3N4/SiC ceramics were significantly decreased due to the increase of porosity. The main phase compositions of samples were β-Si3N4 and SiC. Moreover, the liquid phases Y-Si-O-N and Ce-Si-O-N were observed after adding Y2O3 and CeO2 respectively. It also indicated that for Si3N4/SiC composite ceramics, the high aspect ratio β-Si3N4 overlapped with each other and closely bonded with glass phase could improve flexure strength effectively. Besides, the SiC crystal grains mainly existed in grain boundary, which could inhibit the secondary recrystallization to avoid that the decrease of flexural strength caused by the overgrowth of β-Si3N4 grains.

Fabrication and Precision Electromachining Technology of ZrB2-SiC Ceramic Composites

2013 ◽  
Vol 753-755 ◽  
pp. 267-270
Author(s):  
Wen Bo Han ◽  
Ji Hong Zhang ◽  
Hong Qing Yang ◽  
Guo Zhi Ding
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Carbon Black ◽  
Ceramic Composites ◽  
Argon Atmosphere ◽  
Uniaxial Pressure ◽  
Complicated Structure ◽  
Sic Ceramic

ZrB2-SiC ceramic composites with the addition of carbon black were fabricated by hot pressed sintering at 1900 °C for 60 min at a uniaxial pressure of 30 MPa in an argon atmosphere. The mechanical properties of ZrB2-SiC ceramic composites were improved, adapting to the use requirements of ceramic parts. The precision electromachining technology of complicated structure components was investigated. The processing surface roughness was evaluated.

scholarly journals Mechanical Properties of AlN-SiC Ceramic Composites Synthesized by Pressureless Sintering and Post-HIP Treatment.

1995 ◽  
Vol 42 (12) ◽  
pp. 1452-1456
Author(s):  
Jing-Feng Li ◽  
Mineo Asano ◽  
Yoshimasa Kobayashi ◽  
Akira Kawasaki ◽  
Ryuzo Watanabe
Keyword(s):  
Mechanical Properties ◽  
Ceramic Composites ◽  
Pressureless Sintering ◽  
Sic Ceramic

Sintering of B4C-SiC Powder Obtained In Situ by Carbothermal Reduction

2008 ◽  
Vol 591-593 ◽  
pp. 493-497 ◽  
Author(s):  
Rosa Maria da Rocha ◽  
Francisco Cristóvão Lourenço de Melo
Keyword(s):  
Carbothermal Reduction ◽  
High Hardness ◽  
Argon Atmosphere ◽  
Synthesis Reaction ◽  
Hot Press ◽  
Sic Composites ◽  
C 30 ◽  
Hot Press Sintering ◽  
Boron Carbide B4c

Boron carbide (B4C) and silicon carbide (SiC) are materials with high hardness and low density what make them very useful in various applications, such armor plates. Hot press sintering of B4C-SiC composites was studied. The powder mixture was obtained in situ by carbothermal reduction using B2O3, SiO2 and carbon black as precursors. Seeds of commercial B4C and SiC were used to accelerate the synthesis reaction. Compositions were prepared to obtain powders after carbothermal reduction with 10, 30 and 50 wt% of SiC. Carbothermal reaction was conducted in argon atmosphere at temperatures up to 1700 °C. The synthesized powders were analyzed by DRX and SEM. Hot pressing at 1850 °C/30 min (20 MPa) in argon atmosphere was applied. Densities higher than 93% of theoretical density and microhardness of 34 GPa were achieved for hot pressed samples.

Pressureless Sintering of High-Density ZrB2?SiC Ceramic Composites

2006 ◽  
Vol 89 (11) ◽  
pp. 3589-3592 ◽  
Author(s):  
Yongjie Yan ◽  
Zhengren Huang ◽  
Shaoming Dong ◽  
Dongliang Jiang
Keyword(s):  
Ceramic Composites ◽  
High Density ◽  
Pressureless Sintering ◽  
Sic Ceramic

Processing and Properties of (Zr,Hf)B2-SiC Ceramic Composites

2018 ◽  
Vol 281 ◽  
pp. 438-443 ◽  
Author(s):  
Xiao Tong Zhao ◽  
Hai Long Wang ◽  
Gang Shao ◽  
Bing Bing Fan ◽  
Hong Xia Lu ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Solid Solutions ◽  
Hot Pressing ◽  
Ceramic Composites ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sic Ceramic ◽  
Sic Composites

Different molar ratio of HfB2and ZrB2had been mixed, and 30 vol.% SiC was selected as sintering additives. The mixing powders were sintered by hot pressing at 1900 °C for 1 h under a pressure of 20 MPa in Ar atmosphere. X-ray diffraction, scanning microscopy and Archimedes’s method were used to characterize the phase, microstructure and density of the sintered composites. Meanwhile, the hardness, the fracture toughness and flexural strength of the obtained composites were considered too. It can be found that the (Zr,Hf)B2solid solutions were formed by HfB2and ZrB2during the sintering. The flexural strength of (Zr,Hf)B2-SiC composites increased with the amount of HfB2increasing, which reached (332±40) MPa for the composites content of 70% HfB2. Which fracture toughness was (2.22±0.25) MPa·m1/2. The highest Vickers’ harness of was (24.8±3.4) GPa for the composites content of 50% HfB2.

Sign in / Sign up

Export Citation Format

Share Document