Effect of Sintering Additives on Fabrication Properties of Liquid Phase Sintered SiC

2005 ◽  
Vol 297-300 ◽  
pp. 2539-2544 ◽  
Author(s):  
Han Ki Yoon ◽  
Yi Hyun Park ◽  
Joon Soo Park ◽  
Akira Kohyama
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Liquid Phase ◽  
Hot Pressing ◽  
Bending Test ◽  
Average Particle ◽  
Pressing Method ◽  
Sintering Additives ◽  
Temperature And Pressure ◽  
Sic Composites

SiC has been extensively studied for high temperature components in advanced energy system and gas turbine because of its excellent high temperature mechanical properties and good thermal-chemical stability etc. However, the brittle characteristics of SiC such as low fracture toughness and low strain-to fracture still impose a severe limitation on practical applications of SiC materials. For these reasons, SiCf/SiC composites can be considered as a promising for various structural materials, because of their good fracture toughness compared with monolithic SiC. But, high temperature and pressure lead to the degradation of the reinforcing fiber during the hot pressing. Therefore, reduction of sintering temperature and pressure is key requirements for the fabrication of SiCf/SiC composites by hot pressing method. In the present work, monolithic Liquid Phase Sintered SiC (LPS-SiC) was fabricated by hot pressing method in Ar atmosphere at 1800oC under 20MPa using Al2O3, Y2O3 and SiO2 as sintering additives. The starting powder was high purity β-SiC nano-powder with an average particle size of 30nm. The characterization of LPS-SiC was investigated by means of SEM and three point bending test. Base on the composition of sintering additives-, microstructure- and mechanical property correlation, the compositions of sintering additives are discussed.

Fabrication and Strength Properties of LPS-SiC Ceramics

2005 ◽  
Vol 287 ◽  
pp. 183-188 ◽  
Author(s):  
Yi Hyun Park ◽  
Dong Hyun Kim ◽  
Han Ki Yoon ◽  
Akira Kohyama
Keyword(s):  
Elastic Modulus ◽  
High Temperature ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Average Particle Size ◽  
Process Temperature ◽  
Average Particle ◽  
Pressing Method ◽  
Temperature And Pressure ◽  
Sic Composites

SiC materials have been extensively studied for high temperature components in advanced energy system and advanced gas turbine. SiCf/SiC composites are promising for various structural materials. But, high temperature and pressure lead to the degradation of the reinforcing fiber during the hot pressing. Therefore, reduction of the process temperature and pressure is key requirements for the fabrication of SiCf/SiC composites by hot pressing method. In the present work, monolithic LPS-SiC was fabricated by hot pressing method at various temperatures. The starting powder was high purity β-SiC nano-powder with an average particle size of 30nm. Compositions of sintering additives were Al2O3 / Y2O3 = 0.7 and 1.5 (wt.%). Monolithic LPS-SiC was evaluated in terms of sintering density, micro-structure, flexural strength, elastic modulus and so on. Sintered density, flexural strength and elastic modulus of fabricated LPS-SiC increased with increasing the process temperature. Particularly, relative density of LPS-SiC fabricated at 1820oC with additive composition of Al2O3/Y2O3=1.5(wt.%) was 95%. Also, flexural strength and elastic modulus were 900MPa and 220GPa, respectively. In the fracture surface of this specimen, the size and shape of SiC grains grew up and changed. Also, tortuous crack paths and occurrence of interfacial debonding were observed.

Tribological Characteristics Manufactures SiC by Liquid Phase Sintered Method

2006 ◽  
Vol 324-325 ◽  
pp. 1177-1180
Author(s):  
Won Jo Park ◽  
Sun Chul Huh ◽  
Sung Ho Park ◽  
Hong Tae Song
Keyword(s):  
Wear Resistance ◽  
Liquid Phase ◽  
Coefficient Of Thermal Expansion ◽  
Average Particle Size ◽  
High Temperature Strength ◽  
Average Particle ◽  
Pressing Method ◽  
Sintering Additives ◽  
Resistance To Oxidation ◽  
Sic Composites

SiC materials have excellent high temperature strength, low coefficient of thermal expansion, good resistance to oxidation and good thermal and chemical stability etc. In this study, monolithic liquid phase sintered SiC (LPS-SiC) was made by hot pressing method with nano-SiC powder an average particle size is 30nm and less. Alumina (Al2O3), yttria (Y2O3) and silica (SiO2) particles were used for sintering additives. To investigate effects of SiO2, Al2O3/Y2O3 composition was fixed and then ratios of SiO2 were changed as seven kinds. Materials have been sintered for 1 hour at 1760, 1780 and 1800 under the pressure of 20MPa. The system of sintering additives which affects a property of sintering as well as the influence depending on compositions of sintering additives were investigated by measurement of density, mechanical properties such as Vickers hardness and sliding wear resistance were investigated to make sure of the optimum condition which is about matrix of SiCf/SiC composites. The abrasion test condition applies to load of 20N at 100rpm for 20min. Sintered density, abrasion property of fabricated LPS-SiC increased with increasing the sintering temperature. In case of LPS-SiC with low SiO2 content, has very excellent wear resistance.

Fracture Toughness of Liquid Phase Sintered SiC by Using Indentation Fracture Method

2005 ◽  
Vol 297-300 ◽  
pp. 137-142
Author(s):  
Hun Chae Jung ◽  
Han Ki Yoon ◽  
Bu Ahn Kim ◽  
Joon Soo Park ◽  
Akira Kohyama
Keyword(s):  
Fracture Toughness ◽  
Liquid Phase ◽  
Coefficient Of Thermal Expansion ◽  
Average Particle Size ◽  
Chemical Vapor Deposition Method ◽  
High Temperature Strength ◽  
Average Particle ◽  
Indentation Fracture ◽  
Pressing Method ◽  
Sintering Additives

SiC materials have excellent high temperature strength, low coefficient of thermal expansion, good resistance to oxidation and good thermal and chemical stability etc. However, the brittle characteristics of SiC such as low fracture toughness and low strain-to fracture still impose a severe limitation on practical applications of SiC materials. Therefore, in the interests of safety, we are required to measure fracture toughness of materials. In the present work, monolithic Liquid Phase Sintered SiC (LPS-SiC) was fabricated by hot pressing method under 20MPa using sintering additives at different temperature such as 1760oC, 1780oC, 1800oC and 1820oC. The starting powder was high purity β-SiC nano-powder with an average particle size of 30nm. Compositions of sintering additives were Al2O3 / Y2O3 = 0.7 and 1.5 (wt. %). Monolithic LPS-SiC was evaluated in terms of sintering density, hardness and fracture toughness through indentation fracture method by the Vickers hardness tester. Sintered density, hardness and fracture toughness of fabricated LPS-SiC increased with the increase of sintering temperature. They are higher than those of fabricated SiC by the chemical vapor deposition method.

Effect of Processing Condition on the Microstructure and Mechanical Properties of Ti3SiC2/SiC Composites

2010 ◽  
Vol 658 ◽  
pp. 352-355 ◽  
Author(s):  
Hong Feng Yin ◽  
Lin Lin Lu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Processing Condition ◽  
High Porosity ◽  
Pressing Temperature ◽  
Pressing Method ◽  
Microstructure And Mechanical Properties ◽  
Sic Composites

Ti3SiC2/SiC composites were fabricated by reactive hot pressing method. Effect of processing condition on the microstructure and mechanical properties of the composites were investigated. The results showed that: (1) Hot-pressing temperature influenced the phase constituent of Ti3SiC2/SiC composites. The flexural strength and fracture toughness of composites increased with hot pressing temperature. (2) The flexural strength and fracture toughness of composites increased when the content of SiC was increased. When the SiC content was 30wt% the flexural strength and fracture toughness of Ti3SiC2/SiC composite were 371MPa and 6.9MPa•m1/2 respectively. However, when the content of SiC reached 50wt%, the flexural strength and fracture toughness of composites decreased due to high porosity in the composites. (3) The flexural strength and fracture toughness of composites increased with the particle size of SiC added in composites. (4) Ti3SiC2/SiC composites were non-brittle at room temperature.

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.

scholarly journals Mechanical Properties of SiC Short-Fibre-Reinforced SiC Composites Fabricated by Tape Casting and Hot-Pressing

2005 ◽  
Vol 14 (3) ◽  
pp. 096369350501400
Author(s):  
Jae-Seol Lee ◽  
Toyohiko Yano
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Hot Pressing ◽  
Tape Casting ◽  
Short Fibre ◽  
Mechanical And Thermal Properties ◽  
Sintering Additives ◽  
Densification Temperature ◽  
Short Fibres ◽  
Sic Composites

In order to examine the effects of sintering additives on microstructure and mechanical properties of SiC short-fibre-reinforced SiC composites, a ZrO2-Y2O3-Al2O3 additive system was applied in this study. The aim of this study was to investigate the influence of the sintering additives on the mechanical properties of SiC/SiC composites using Tyranno SA short fibres. A ZrO2-Y2O3-Al2O3 mixture was chosen for fabrication of the short-fibre-reinforced SiC composites as sintering additives because of their relatively low densification temperature and non-reactivity with SiC. Compare with the previous results, the influence of sintering additives on the mechanical and thermal properties of the SiC/SiC composites was discussed.

Effect of Y2O3 on the Sintering, Mechanical and Dielectric Properties of Mullite/h-BN Composites

2016 ◽  
Vol 848 ◽  
pp. 28-31
Author(s):  
Han Jin ◽  
Yong Feng Li ◽  
Zhong Qi Shi ◽  
Hong Yan Xia ◽  
Guan Jun Qiao
Keyword(s):  
Fracture Toughness ◽  
Dielectric Constant ◽  
Phase Composition ◽  
High Temperature ◽  
Dielectric Properties ◽  
Liquid Phase ◽  
Flexural Strength ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Different Temperatures

Mullite/10 wt. %h-BN composites with 5 wt. % Y2O3 additive were fabricated by pressureless sintering at different temperatures. The densification, phase composition, microstructure, mechanical and dielectric properties of the mullite/h-BN composites were investigated. With the addition of Y2O3, the sintering temperature of the mullite/h-BN composites declined, while the density, mechanical and dielectric properties all increased. The addition of Y2O3 promoted the formation of liquid phase at high temperature, which accelerated the densification. Besides, Y2O3 particles which were located at the grain boundaries inhibited the grain growth of mullite matrix. For the mullite/h-BN composites with Y2O3 additive, the appropriate sintering temperature was about 1600°C. The relative density, flexural strength, fracture toughness and dielectric constant of the Y2O3 doped mullite/h-BN composite sintered at 1600 °C reached 82%, 135 MPa, 2.3 MPa·m1/2 and 4.9, respectively.

Microstructure and Mechanical Properties of TiC/Ti3AlC2 In Situ Composites Prepared by Hot Pressing Method

2015 ◽  
Vol 816 ◽  
pp. 200-204 ◽  
Author(s):  
Miao Miao Ruan ◽  
Xiao Ming Feng ◽  
Tao Tao Ai ◽  
Ning Yu ◽  
Kui Hua
Keyword(s):  
Fracture Toughness ◽  
Flexural Strength ◽  
Vickers Hardness ◽  
Hot Pressing ◽  
Sintering Temperature ◽  
Powder Mixtures ◽  
Pressing Method ◽  
Hot Pressing Sintering ◽  
Sintering Method

TiC/Ti3AlC2 composites were successfully prepared by hot-pressing sintering method from the elemental powder mixtures of Ti, Al and TiC. A possible reaction mechanism was investigated by XRD. The density, Vickers hardness, flexural strength, and fracture toughness of the TiC/Ti3AlC2 composites were also measured. At 660 °C, Al melted and reacted with Ti to form TiAl3. At 900 °C, TiAl3 reacted with TiC and Ti to form Ti2AlC. At 1100 °C, Ti2AlC reacted with TiC to form Ti3AlC2. Increasing the sintering temperature, the content of Ti3AlC2 increased. The TiC/Ti3AlC2 composites had excellent performance after sintered at 1100 °C, the density, Vickers hardness, flexural strength and fracture toughness of the composite were 4.35 g/cm3, 4.72 GPa, 566 MPa and 6.18 MPa·m1/2, respectively.

scholarly journals Beneficial effect of low BN additive on densification and mechanical properties of hot-pressed ZrB2–SiC composites

2021 ◽  
Vol 1 (2) ◽  
pp. 69-75
Author(s):  
Saber Haghgooye Shafagh ◽  
Shapour Jafargholinejad ◽  
Siyamak Javadian
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Crack Deflection ◽  
Crack Branching ◽  
Pressing Method ◽  
X Ray ◽  
Sic Composites ◽  
Different Characteristics ◽  
Scanning Electron ◽  
Consolidation Behavior

The incorporation of 1 wt% hexagonal BN (hBN) into ZrB2–30 vol% SiC could noticeably better the fracture toughness, hardness, and consolidation behavior of this composite. This research intended to scrutinize the effects of various amounts of hBN (0–5 wt%) on different characteristics of ZrB2–SiC materials. The hot-pressing method under 10 MPa at 1900 °C for 120 min was employed to sinter all designed specimens. Afterward, the as-sintered samples were characterized using X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), and Vickers technique. The hBN addition up to 1 wt% improved relative density, leading to a near fully dense sample; however, the incorporation of 5 wt% of such an additive led to a composite containing more than 5% remaining porosity. The highest Vickers hardness of 23.8 GPa and fracture toughness of 5.7 MPa.m1/2 were secured for the sample introduced by only 1 wt% hBN. Ultimately, breaking large SiC grains, crack bridging, crack deflection, crack branching, and crack arresting were introduced as the chief toughening mechanisms in the ZrB2–SiC–hBN system.

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