CHARACTERIZATION OF LIQUID PHASE SITERED SIC AND SIC/SIC COMPOSITE MATERIALS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2916-2921 ◽  
Author(s):  
MOON HEE LEE ◽  
SANG PILL LEE ◽  
KWAN DO HUR
Keyword(s):  
Liquid Phase ◽  
Flexural Strength ◽  
Fracture Behavior ◽  
Sintered Density ◽  
Secondary Phase ◽  
Sintering Additives ◽  
Catastrophic Fracture ◽  
Sic Composites ◽  
Composition Ratios

The characterization of liquid phase sintered(LPS) SiC based materials has been investigated with the analysis of microstructure and flexural strength. Especially, LPS - SiC materials were examined for the variation of test temperature and composition ratios ( Al 2 O 3,/ Y 2 O 3) of sintering additives. LPS - SiC based materials were fabricated by hot pressing(HP) associated with the liquid phase formation of sintering additives( Al 2 O 3, Y 2 O 3). LPS - SiCf / SiC composites were also fabricated with plane-woven(PW) Tyranno-SA fibers without an interfacial layer. LPS - SiC materials showed a dense morphology with the creation of the secondary phase like YAG. The composition ratio of sintering additives led to the variation of sintered density and flexural strength. The flexural strength of LPS - SiC materials was greatly decreased at the temperature higher than 1000°C. LPS - SiCf / SiC composites represented an average flexural strength of about 260 MPa, accompanying the catastrophic fracture behavior without any full-out phenomena.

Characterization of Liquid Phase Sintered SiC Ceramics with Oxide Additive Materials

2006 ◽  
Vol 326-328 ◽  
pp. 1853-1856 ◽  
Author(s):  
Sang Ll Lee ◽  
Yun Seok Shin ◽  
Jin Kyung Lee ◽  
Joon Hyun Lee ◽  
Jun Young Park
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Liquid Phase ◽  
Flexural Strength ◽  
Applied Pressure ◽  
Sic Ceramics ◽  
Additive Materials ◽  
Composition Ratios ◽  
Average Size

This paper dealt with the fabricating process of liquid phase sintered (LPS) SiC ceramics containing the oxide additives of Al2O3 and Y2O3, in conjunction with the evaluation of their mechanical properties. LPS-SiC ceramics was sintered at the temperature of 1820 oC under an applied pressure of 20 MPa and a pressure holding time of 2 hour. A commercial SiC powder with an average size of about 0.3 μm was used as a starting powder. LPS-SiC ceramics with additive composition ratios of 1.5 and 2.3 (Al2O3/Y2O3) represented an excellent density of about 3.2 Mg/m3. LPS-SiC ceramics had a flexural strength of about 800 MPa and a fracture toughness of about 8.0 MPa⋅m0.5 at an additive composition ratio (Al2O3/Y2O3) of 1.5.

Effect of BN Interphase Coating and PIP Cycles on the Mechanical Properties of VSI SiC/SiC Composites

2015 ◽  
Vol 816 ◽  
pp. 84-90
Author(s):  
Bao Lin Liu ◽  
Rong Jun Liu ◽  
Chang Rui Zhang ◽  
Ying Bin Cao
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Fracture Behavior ◽  
Residual Porosity ◽  
Residual Carbon ◽  
Positive Role ◽  
Sic Fibers ◽  
Pull Out ◽  
Catastrophic Fracture ◽  
Sic Composites

2.5D SiC/SiC composites with and without BN interphase coating were fabricated by VSI process from SiC/C preforms that were produced after 3, 4 and 5 PIP C cycles, respectively. The effect of the BN interphase coating and PIP C cycles on the mechanical properties and microstructure of the composites was investigated. The results indicated that the composites with or without BN interphase coating exhibited catastrophic fracture behavior. Both the excess residual carbon and BN interphase coating played a positive role in protecting the SiC fibers from silication by vapor silicon, which accounted for the less obvious fibers pull-out phenomenon that occurred in the composites. The PIP cycles had an influence on the residual porosity and the content of the newly developed SiC in the composites, and therefore the mechanical properties of the composites were influenced. The composites fabricated from preforms after 4 PIP C cycles and containing BN interphase coating have a flexural strength of 122.5 MPa and a modulus of 86.5 GPa.

Characterization of Fiber-Reinforced SiC Composites by Precursor-Pyrolysis and Hot-Pressing

2007 ◽  
Vol 280-283 ◽  
pp. 1305-1308
Author(s):  
Xin Bo He ◽  
Xuan Hui Qu ◽  
Chang Rui Zhang ◽  
Xin Gui Zhou
Keyword(s):  
Mechanical Properties ◽  
Hot Pressing ◽  
Fracture Behavior ◽  
Matrix Interface ◽  
Direct Reactions ◽  
Fiber Matrix Interface ◽  
Fiber Matrix ◽  
Sic Composites ◽  
Strength Retention

CF/SiC and Hi-Nicalon/SiC composites were prepared by precursor pyrolysis-hot pressing, and the microstructure and fracture behavior of the composites were investigated. Because of a strongly bonded fiber/matrix interface primarily resulting from the direct reactions between the fibers and matrix, Hi-Nicalon/SiC composite exhibited a typical brittle fracture behavior. However, CF/SiC composite displayed a tough fracture behavior with extensive fiber pullout, which was primarily attributed to a weakly bonded fiber/matrix interface as well as higher strength retention of the fibers. As a result, CF/SiC composite achieved better mechanical properties of 691.6 MPa in strength and 20.7 MPa•m1/2 in toughness, which were much higher than those of Hi-Nicalon/SiC composite.

Interface Formation of Unidirectional SiCf/SiC Composites by Electrophoretic Deposition Method

2014 ◽  
Vol 617 ◽  
pp. 213-216 ◽  
Author(s):  
Katsumi Yoshida ◽  
Hiroyuki Akimoto ◽  
Akihiro Yamauchi ◽  
Toyohiko Yano ◽  
Masaki Kotani ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ductile Fracture ◽  
Electrophoretic Deposition ◽  
Fracture Behavior ◽  
Deposition Method ◽  
Interface Formation ◽  
Fiber Pullout ◽  
Sic Fibers ◽  
Sintering Additives ◽  
Sic Composites

C-and BN-interphases on SiC fibers for unidirectional SiCf/SiC composites were formed by EPD process, and their microstructure and mechanical properties were investigated. Whereas the C-SiCf/SiC composites showed a pseudo-ductile fracture behavior with large amount of fiber pullout, the BN-SiCf/SiC composites fractured in a brittle manner without fiber pullout in spite of sufficient thickness of BN interphase. It is inferred from the results of EDS that sintering additives would react with h-BN-interphase, and the interphase did not act effectively for toughening the SiCf/SiC composites.

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.

Liquid-Phase Sintered Silicon Carbide with Aluminum Nitride and Rare-Earth Oxide Additives

2006 ◽  
Vol 317-318 ◽  
pp. 111-114 ◽  
Author(s):  
Mikinori Hotta ◽  
Naoya Enomoto ◽  
Junichi Hojo
Keyword(s):  
Liquid Phase ◽  
Sintered Density ◽  
Secondary Phase ◽  
Rare Earth Oxide ◽  
Liquid Phase Sintering ◽  
Α Phase ◽  
Maximum Value ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintered Silicon

SiC was sintered with AlN and Y2O3 as sintering additives by spark plasma sintering (SPS). Using nano-sized β-SiC powder as the starting material, the sintered density reached about 95% of theoretical at 1800-2000oC for 10min. The β to α phase transformation of SiC was not found by XRD. The secondary phase such as Y2O3 decreased as the firing temperature was elevated, and β-SiC monophase was identified at 2000oC. It seems that the residual intergranular glassy phase is present between the SiC grains. Significant SiC grain growth was observed at 1800-1900oC by SEM. The grain size decreased with increasing amount of AlN additive. The maximum value of flexural strength of the sample reached approximately 800MPa. These results are discussed on the basis of the liquid-phase sintering mechanism in AlN-Y2O3 and Al2O3-Y2O3 systems.

Preparation of Cf/SiC Composites by Liquid Silicon Infiltration

2010 ◽  
Vol 434-435 ◽  
pp. 103-105 ◽  
Author(s):  
Chun Peng Wang ◽  
Jie Tang ◽  
Hai Lin Liu ◽  
Yan Li Huo ◽  
Yu Feng Chen ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Fracture Behavior ◽  
Binding Strength ◽  
Phenol Resin ◽  
Pure Carbon ◽  
Sic Composites ◽  
Fiber Preforms

The Cf/SiC made from carbon fiber preforms infiltrated by phenol resin, pure carbon slurry and aqueous C/SiC slurry showed different binding strength between carbon fiber and SiC matrix, thus influenced the fracture behavior of the composite. The fracture toughness of the Cf/SiC composites with the value of 9.82MPa•m1/2,improved remarkably compared with reaction- bonded silicon carbide (RBSC). But the flexural strength was less than 100 MPa, because of the existence of considerable amount of pores in C/SiC composites.

Mechanical and Tribological Properties of 3D Carbon Fiber Reinforced SiC Composites Prepared by Liquid Silicon Infiltration

2010 ◽  
Vol 434-435 ◽  
pp. 28-32 ◽  
Author(s):  
Hai Jun Zhou ◽  
Shao Ming Dong ◽  
Xiang Yu Zhang ◽  
Jin Shan Yang ◽  
Bo Lu
Keyword(s):  
Wear Rate ◽  
Tribological Properties ◽  
Fracture Behavior ◽  
Liquid Silicon ◽  
Infiltration Process ◽  
Mechanical And Tribological Properties ◽  
Catastrophic Fracture ◽  
Sic Composites ◽  
The Stability ◽  
Long Fibers

C/SiC composites were prepared by liquid silicon infiltration process, and their microstructure, mechanical and tribological properties were studied in this paper. The results showed that the composites demonstrated non-catastrophic fracture behavior with long fibers pulled out and about 115 MPa flexural strength. The stability of coefficient of friction (COF) was improved and wear rate demonstrated a linear variation with the increasing of rotation speeds. However, wear rate exhibited a higher value (~3.6 μg/m) under a higher load (~150 N), even though the COF curves for C/SiC composites showed no significant changes.

Sign in / Sign up

Export Citation Format

Share Document