Effects of Carbon Black on Microstructure and Mechanical Properties of Hot Pressed ZrB2-SiC Ceramics

2010 ◽  
Vol 434-435 ◽  
pp. 185-188 ◽  
Author(s):  
Xin Sun ◽  
Xing Hong Zhang ◽  
Zhi Wang ◽  
Wen Bo Han ◽  
Chang Qing Hong
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Carbon Black ◽  
Potential Method ◽  
Ceramic Composites ◽  
Grain Refining ◽  
Ultra High Temperature Ceramics ◽  
Sic Ceramics ◽  
Microstructure And Mechanical Properties

Abstract. ZrB2-SiC ultra-high temperature ceramics (UHTCs) was hot-pressed at a temperature of 1900°C with the addition of carbon black as a reinforcing phase. Microstructure and mechanical properties were investigated. Analysis revealed that the amount of carbon black had a significant influence on the sinterability and mechanical properties of ZrB2-SiC ceramics. When a small amount ( < 10 vol.%) of carbon black was introduced, it may react with oxide impurities (i.e. ZrO2, B2O3 and SiO2) present on the surface of the starting powder, thus promote the densification and grain refining of ZrB2-SiC ceramics. As a result, the mechanical properties including flexural strength and fracture toughness were improved. However, with the further adoption of carbon black, mechanical properties were not improved much, which could be attributed to the redundant phase at grain boundaries. The results presented here point to a potential method for improving densification, microstructure and mechanical properties of ZrB2-based ceramic composites.

Microstructure and Mechanical Properties of SiC Whisker-Reinforced ZrB2 Ultra-High Temperature Ceramic

2008 ◽  
Vol 368-372 ◽  
pp. 1730-1732 ◽  
Author(s):  
Ping Hu ◽  
Xing Hong Zhang ◽  
Jie Cai Han ◽  
Song He Meng ◽  
Bao Lin Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Temperature ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Room Temperature ◽  
Pressing Temperature ◽  
Sintering Time ◽  
Microstructure And Mechanical Properties ◽  
Ultra High Temperature

SiC whisker-reinforced ZrB2 matrix ultra-high temperature ceramic were prepared at 2000°C for 1 h under 30MPa by hot pressing and the effects of whisker on flexural strength and fracture toughness of the composites was examined. The flexural strength and fracture toughness are 510±25MPa and 4.05±0.20MPa⋅m1/2 at room temperature, respectively. Comparing with the SiC particles-reinforced ZrB2 ceramic, no significant increase in both strength and toughness was observed. The microstructure of the composite showed that the SiC whisker was destroyed because the SiC whisker degraded due to rapid atom diffusivity at high temperature. The results suggested that some related parameters such as the lower hot-pressing temperature, a short sintering time should be controlled in order to obtain SiC whiskerreinforced ZrB2 composite with high properties.

Synthesis of SiC Ceramics from Coal Gangue

2005 ◽  
Vol 486-487 ◽  
pp. 378-381 ◽  
Author(s):  
Shu Hai Jia
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Carbon Black ◽  
Bending Strength ◽  
Coal Gangue ◽  
Holding Time ◽  
Crystal Phase ◽  
Sic Ceramics ◽  
N2 Atmosphere

The synthesis and the sintering of SiC from coal gangue by carbothermal synthesized in N2 atmosphere are studied. The material, 5 percent carbon black added and sintered at 1400°C for 2 hours, had good properties and a bending strength of 137.8MPa. Too high temperature or too long holding time made the properties of the material to decrease. β-SiC found by observing the microstructure is a major crystal phase in the synthesized ceramics, which would lead to fine mechanical properties.

Microstructure and Mechanical Properties of Hot Pressed ZrC-SiC-ZrB2 Composites

2010 ◽  
Vol 434-435 ◽  
pp. 173-177 ◽  
Author(s):  
Bao Xia Ma ◽  
Wen Bo Han ◽  
Xing Hong Zhang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Grain Size ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Ceramic Composites ◽  
Strong Function ◽  
Slight Tendency ◽  
Microstructure And Mechanical Properties

Ternary ZrC-SiC-ZrB2 ceramic composites were prepared by hot pressing at 1900 °C for 60 min under a pressure of 30 MPa in argon. The influence of ZrB2 content on the microstructure and mechanical properties of ZrC-SiC-ZrB2 composites was investigated. Examination of SEM showed that the microstructure of the composites consisted of the equiaxed ZrB2, ZrC and SiC grains, and there was a slight tendency of reduction for grain size in ZrC with increasing ZrB2 content. The hardness increased considerably from 23.3 GPa for the ZS material to 26.4 GPa for the ZS20B material. Flexural strength was a strong function of ZrB2 content, increasing from 407 MPa without ZrB2 addition to 627 MPa when the ZrB2 content was 20vol.%. However, the addition of ZrB2 has little influence on the fracture toughness, ranging between 5.5 and 5.7 MPam1/2.

Microstructure and Mechanical Properties of Heat-Resistant Silicon Carbide Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1409-1413 ◽  
Author(s):  
Young Wook Kim ◽  
Yong Seong Chun ◽  
Sung Hee Lee ◽  
Ji Yeon Park ◽  
Toshiyuki Nishimura ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Carbide ◽  
Intergranular Phase ◽  
Sintering Additives ◽  
Heat Resistant ◽  
Sic Ceramics ◽  
Microstructure And Mechanical Properties ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics

There has been a great progress in the development of heat-resistant silicon carbide ceramics, owing to the better understanding of composition-microstructure-properties relations. Based on the progress, it has been possible to fabricate heat-resistant SiC ceramics with improved fracture toughness. In this paper, three rare-earth oxides (Re2O3, Re=Er, Lu, and Sc) in combination with AlN were used as sintering additives for a β-SiC containing 1 vol% α-SiC seeds. The effect of intergranular phase, using Re2O3 and AlN as sintering additives, on the microstructure and mechanical properties of liquid-phasesintered, and subsequently annealed SiC ceramics were investigated. The microstructure and mechanical properties were strongly influenced by the sintering additive composition, which determines the chemistry and structure of IGP. The strength and fracture toughness of the Lu2O3-doped SiC were ∼700 MPa at 1400oC and ∼6 MPa.m1/2 at room temperature, respectively. The beneficial effect of the new additive compositions on high-temperature strength was attributed to the crystallization of the intergranular phase.

scholarly journals Effect of Ti Addition on the Microstructure and Mechanical Properties of SiC Matrix Composites Infiltrated by Al–Si (10 wt.%)–xTi Alloy

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 318
Author(s):  
Yajun Yu ◽  
An Du ◽  
Xue Zhao ◽  
Yongzhe Fan ◽  
Ruina Ma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Intermetallic Compounds ◽  
Bending Strength ◽  
Al Alloys ◽  
Al Alloy ◽  
Matrix Composites ◽  
Sic Ceramics ◽  
Microstructure And Mechanical Properties ◽  
Ti Addition

This paper proposes a simple reactive melt infiltration process to improve the mechanical properties of silicon carbide (SiC) ceramics. SiC matrix composites were infiltrated by Al–Si (10 wt.%)–xTi melts at 900 °C for 4 h. The effects of Ti addition on the microstructure and mechanical properties of the composites were investigated. The results showed that the three-point bending strength, fracture toughness (by single-edge notched beam test), and fracture toughness (by Vickers indentation method) of the SiC ceramics increased most by 34.3%, 48.5%, and 128.5%, respectively, following an infiltration with the Al–Si (10 wt.%)–Ti (15 wt.%) melt. A distinct white reaction layer mainly containing a Ti3Si(Al)C2 phase was formed on the surface of the composites infiltrated by Al alloys containing Ti. Ti–Al intermetallic compounds were scattered in the inner regions of the composites. With the increase in the Ti content (from 0 to 15 wt.%) in the Al alloy, the relative contents of Ti3Si(Al)C2 and Ti–Al intermetallic compounds increased. Compared with the fabricated composite infiltrated by an Al alloy without Ti, the fabricated composites infiltrated by Al alloys containing Ti showed improved overall mechanical properties owing to formation of higher relative content Ti3Si(Al)C2 phase and small amounts of Ti–Al intermetallic compounds.

Effect of Forming Pressure on Microstructure and Mechanical Properties of B4C- SiC-Si Ceramic Composites

2018 ◽  
Vol 768 ◽  
pp. 152-158 ◽  
Author(s):  
Hui Zong ◽  
Cui Ping Zhang ◽  
Hong Qiang Ru ◽  
He Huang ◽  
Jing Hui Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Ceramic Composites ◽  
Volume Density ◽  
Molten Silicon ◽  
X Ray Diffraction ◽  
Universal Testing ◽  
Microstructure And Mechanical Properties ◽  
Infiltration Method

B4C-SiC-Si ceramic composites were fabricated based on molten silicon infiltration method. The influence of preforms'forming pressure on the microstructure and mechanical properties of B4C-SiC-Si ceramic composites was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron universal testing machines, etc. The results showed that the ceramic consists of B4C, B12(C,Si,B)3, SiC and Si phases. The microstructure analysis showed that: the volume percent of free silicon decreased with the increase in forming pressures. The Vikers-hardness of B4C-SiC-Si ceramic composites increased, while the bending strength and fracture toughness both increased initially and then decreased with the increase in forming pressures of which the optimal pressure is 200 MPa. The optimum bending strength, fracture toughness and Vikers-hardness of the obtained B4C-SiC-Si ceramic composites are 319±13 MPa, 4.9±0.1 MPa·m1/2and 24±1 GPa, respectively. The volume density and open porosity of the obtained B4C-SiC-Si ceramic composites are 2.58 g/cm3and 0.19 %, respectively.

Formation of tough interlocking microstructure in ZrB2–SiC-based ultrahigh-temperature ceramics by pressureless sintering

2009 ◽  
Vol 24 (7) ◽  
pp. 2428-2434 ◽  
Author(s):  
Ji Zou ◽  
Guo-Jun Zhang ◽  
Yan-Mei Kan
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Raw Materials ◽  
Pressureless Sintering ◽  
Sic Ceramics ◽  
Microstructure And Mechanical Properties ◽  
Ultrahigh Temperature

A self-reinforced ultrahigh-temperature ceramic (UHTC) with elongated ZrB2 grains has been successfully densified by pressureless sintering using commercially available ZrB2, SiC, and WC powders as raw materials. Benefiting from the unique interlocking microstructure, this material had improved strength (518 ± 10 MPa) and higher fracture toughness (6.5 ± 0.2 MPa m1/2) compared to ZrB2–SiC ceramics prepared by pressureless sintering. This work provides a new route for tailoring the microstructure and mechanical properties of UHTCs.

Microstructure and Mechanical Properties of C/SiC Composites Prepared at Low Temperatures

2008 ◽  
Vol 368-372 ◽  
pp. 849-851
Author(s):  
Chang Cheng Zhou ◽  
Chang Rui Zhang ◽  
Hai Feng Hu ◽  
Yu Di Zhang ◽  
Zhi Yi Wang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fracture Toughness ◽  
Shear Strength ◽  
High Temperature ◽  
Low Temperatures ◽  
High Performance ◽  
Microstructure And Mechanical Properties ◽  
Potential Applications ◽  
Sic Composites

2D-C/SiC composites with high performance were prepared at temperatures as low as 900 °C. The flexural strength of the composites reached 329.61MPa, the same level as the composites prepared at 1200°C, and shear strength and fracture toughness were 32.14MPa and 14.65MPa·m1/2, respectively. The microstructure and mechanical properties of the composites after heat-treatment at 1600°C were also investigated to determine the potential applications at high temperature.

Microstructure and mechanical properties of novel ternary electroconductive ceramics

2004 ◽  
Vol 19 (11) ◽  
pp. 3343-3352 ◽  
Author(s):  
Diletta Sciti ◽  
Stefano Guicciardi
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Hot Pressing ◽  
Room Temperature ◽  
Matrix Material ◽  
Ceramic Composites ◽  
Microstructure And Mechanical Properties ◽  
Electrical Conductors ◽  
Poor Oxidation Resistance

Electroconductive ceramic composites, constituted of an insulating matrix (a composite AlN-SiC) containing 30 vol% of an electroconductive phase (MoSi2, ZrB2, or ZrC), were densified through hot-pressing. Microstructure and mechanical properties were compared to those of the AlN-SiC matrix material. All the ternary composites are good electrical conductors, with resistivities in the range 0.3 × 10-3to 4 × 10-3Ω·cm. Room temperature properties are improved by the addition of the electroconductive particles. Strength and toughness measurements at high temperature show that MoSi2-containing composite is stable up to 1300 °C (strength 611 MPa, toughness 3.7 MPa·m1/2), whereas ZrB2-containing composite is stable up to 1000 °C. ZrC-containing composite is not suitable for high-temperature applications due to poor oxidation resistance.

Microstructure and Mechanical Properties of ZrB2-Based UHTC via Reactive Hot Pressing

2008 ◽  
Vol 368-372 ◽  
pp. 1737-1739
Author(s):  
Qiang Qu ◽  
Wen Bo Han ◽  
Song He Meng ◽  
Xing Hong Zhang ◽  
Jie Cai Han
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Fracture Toughness ◽  
High Temperature ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Volume Ratio ◽  
Ultra High Temperature Ceramics ◽  
Reactive Hot Pressing

ZrB2-based ultra-high temperature ceramics (UHTCs) were prepared from a mixture powder of Zr/B4C/Si with different ratio via reactive hot pressing. The experimental results showed that the sintering temperature above 1800°C was necessary for enhancing the activity of the powders and thus improving the densification of the product. The sinterability and densification properties of ZrB2-based UHTCs meliorated with the amount of Si increasing. However, many large ZrB2 agglomerates formed when the amount of synthesized SiC in the product reached 25vol%, which led to decrease the mechanical property. The composite had highest mechanical properties when the volume ratio of ZrB2: SiC: ZrC was 73.86:20:6.14, and its flexual strength and the fracture toughness were 645.8MPa and 5.66MPa·m1/2 respectively. The microstructure investigation showed the in-situ formed SiC and ZrC were located in the triple point of ZrB2 grains with a size less than 3μm.

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