Oxidation Resistant Behaviour of Mullite/Yttrium Silicate Multilayer Coating for C/SiC Composites at 1500°C

2014 ◽  
Vol 602-603 ◽  
pp. 430-433 ◽  
Author(s):  
Shuang Zhao ◽  
Xin Gui Zhou ◽  
Hong Lei Wang
Keyword(s):  
Heat Treatment ◽  
Silicon Carbide ◽  
Weight Loss ◽  
Flexural Strength ◽  
Multilayer Coating ◽  
Yttrium Silicate ◽  
Spray Method ◽  
Oxidation Resistant ◽  
Sic Composites ◽  
Original Strength

Continuous carbon fibre reinforced silicon carbide (C/SiC) composites were fabricated by precursor infiltration and pyrolysis (PIP) process, a mullite/yttrium silicate multilayer coating was prepared by plasma spray method as the oxidation protective coating. The efficiency of the coating against oxidation was characterized by means of heat treatment of the C/SiC composites at 1500 °C in static air for 1 hour. The results indicated that the weight loss of the coated composites was only 3.4 %, and the flexural strength of the composites retained 95.3 % of the original strength.

Effect of Sintering Temperature on the Celsian/Yttrium Silicate Oxidation Resistant Coatings for C/SiC Composite

2014 ◽  
Vol 1033-1034 ◽  
pp. 882-886
Author(s):  
Xiao Hui Zheng ◽  
Chun Yu Wang ◽  
Song Tao Ding ◽  
Chi Yong Liang
Keyword(s):  
Silicon Carbide ◽  
Weight Loss ◽  
Sintering Temperature ◽  
Silicate Coating ◽  
Yttrium Silicate ◽  
Carbide Matrix ◽  
Oxidation Resistant ◽  
Silicon Carbide Matrix ◽  
And Performance ◽  
Microstructure And Performance

A novel celsian/yttrium silicate coating was deposited on carbon fiber reinforced silicon carbide matrix (C/SiC) composite, using BaO-Al2O3-SiO2 (BAS) glass andY2O3 powder as starting materials. The effects of sintering temperatures on microstructure and performance of coatings were studied. The results show that the final phases of sintered coatings are composed of celsian, yttrium silicate and remnant glass. The coating are dense, crack-free and pore-free in macroscopic scales when sintered at temperatures above 1400°C. The crystal grains in the coating grow too large, and the coating is loose in microstructure when sintered at temperatures higher than 1450°C. The coated samples sintered at 1450°C for 30min, which have the densest morphology and microstructure, have the lowest weight loss of 0.13 % after oxidation at 1500°C for 90 min.

Effect of Heat Treatment on the Microstructure and Mechanical Properties of Cf/SiC Composites

2007 ◽  
Vol 336-338 ◽  
pp. 1291-1293
Author(s):  
Xin Gui Zhou ◽  
Chang Cheng Zhou ◽  
Chang Rui Zhang ◽  
Ying Bin Cao ◽  
Shi Qin Zou
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fracture Toughness ◽  
Silicon Carbide ◽  
Shear Strength ◽  
Carbon Fiber ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Carbon Coatings ◽  
Sic Composites

3D braided carbon fiber reinforced silicon carbide (3D-Cf/SiC) composites were fabricated by precursor infiltration and pyrolysis(PIP), with carbon coatings prepared by chemical vapor deposition (CVD) before PIP. The effect of 1873K heat treatment on the mechanical properties of Cf/SiC composites were investigated. The results showed that heat treatment before PIP can increase the density of composites and lead to excellent properties of Cf/SiC composites. The flexual strength of the Cf/SiC composites with one cycle of 1873 K heat treatment reached 571 MPa, shear strength 51 MPa, and fracture toughness 18 MPa⋅m1/2.

Sintering Mechanism of MgAl2O4-SiC Composites in Reduction Atmosphere

2012 ◽  
Vol 538-541 ◽  
pp. 2368-2371 ◽  
Author(s):  
Jun Cong Wei ◽  
Chun Hui Gao ◽  
Xiao Juan Yang ◽  
Liang Huo ◽  
Bao Zhong Zhao ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Weight Loss ◽  
Bulk Density ◽  
Apparent Porosity ◽  
Magnesium Aluminate ◽  
Carbide Powder ◽  
Magnesium Aluminate Spinel ◽  
Sintering Mechanism ◽  
Sic Composites ◽  
Silicon Carbide Powder

MgAl2O4-SiC Composites were prepared by using magnesium aluminate spinel and silicon carbide powder as starting materials and the sintering mechanism was investigated at 1600°C in reduction atmosphere. Sintered samples were analyzed using XRD, SEM and EDS. The results show that Alumina-rich spinel and SiCN are formed due to the reactions between spinel and SiC. Weight loss of samples was detected due to SiO formation and volatilization. The bulk density of samples decreases and apparent porosity increases as increasing the content of SiC.

Fabrication and Properties of Cf/SiC Composites Derived from Polysiloxane Precursor

2011 ◽  
Vol 686 ◽  
pp. 419-422
Author(s):  
Tian Heng Xu ◽  
Qing Song Ma ◽  
Zhao Hui Chen
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Elemental Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vacuum Atmosphere ◽  
The Matrix ◽  
Sic Composites

Carbon fiber reinforced silicon carbide composites (Cf/SiC) were derived through precursor infiltration pyrolysis route (PIP) at 1600°C in vacuum atmosphere using polysiloxane as precursor. The matrix of Cf/SiC was characterized by X-ray diffraction and elemental analysis. The results show that crystalline β-SiC can be derived at 1600°C in vacuum from polysiloxane. The flexural strength and fracture toughness of polysiloxane derived from Cf/SiC can reach up to 70 MPa and 2.3MPa·m respectively1/2.

Preparation and Properties of C/SiC Composites via Liquid Silicon Infiltration Process

2013 ◽  
Vol 750-752 ◽  
pp. 70-75 ◽  
Author(s):  
Guang De Li ◽  
Chang Rui Zhang ◽  
Hai Feng Hu ◽  
Yu Di Zhang
Keyword(s):  
Heat Treatment ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Carbon Coating ◽  
Liquid Silicon ◽  
Experimental Result ◽  
Infiltration Process ◽  
Carbon Fiber Felt ◽  
Porosity Ratio ◽  
Sic Composites

Three-dimensional short carbon fiber felt reinforced C/SiC composites were prepared by the liquid silicon infiltration (LSI) process. The influences of different porosity ratios, carbon coating, and heat treatment of C/C substrates, on the properties of C/SiC composites were studied. The optimized porosity ratio is calculated as 40.1% when the volume percent of carbon fiber (including carbon coating) is 23%, and after screening porosity ratio from ~55% to ~20%, the optimized experimental result (39.5%) is highly in accordance with the design value. The C/SiC composite after process parameter optimization, has a flexural strength and modulus of 125 MPa and 120 GPa, respectively. The C/SiC composite without carbon coating has a flexural strength of only 77 MPa, showing carbon coating plays a key role. The heat treatment of C/C substrate at 1600°C also improves the flexural strength of C/SiC composite for nearly 50%, and porosity rearrangement and interface weakening are believed to contribute such improvement.

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.

Strength Degradation Flaws in the Liquid-Phase-Sintered SiC Based Ceramics

2009 ◽  
Vol 409 ◽  
pp. 350-353
Author(s):  
Alexandra Kovalčíková ◽  
Ján Dusza ◽  
Pavol Šajgalík
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Silicon Carbide ◽  
Liquid Phase ◽  
Flexural Strength ◽  
Crack Deflection ◽  
Liquid Phase Sintering ◽  
Crack Branching ◽  
Mechanical Interlocking ◽  
Heat Treated

The effect of the heat treatment on the fracture toughness and flexural strength of the silicon carbide – silicon nitride composites prepared by liquid-phase-sintering was investigated. The results were compared to those obtained for a reference silicon carbide material, prepared by the same fabrication route. The fracture toughness increased from 3.19 to 5.15 MPa.m1/2 due to the toughening mechanisms (crack deflection, mechanical interlocking, crack branching) occurring in the heat treated materials during the crack propagation. However, the flexural strength decreased after the heat treatment of the experimental materials. The strength of the investigated materials was degraded by the presence of processing flaws mainly in the form of pores, clusters of pores, and SiC agglomerates.

EFFECT OF WEIGHT LOSS AND MICROSTRUCTURE BY HEAT TREATMENT AND FABRICATION OF LPS-SIC CERAMICS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4583-4588 ◽  
Author(s):  
HAN-KI YOON ◽  
JOON SOO PARK ◽  
AKIRA KOHYAMA
Keyword(s):  
Heat Treatment ◽  
Weight Loss ◽  
Flexural Strength ◽  
Treatment Temperature ◽  
Test Machine ◽  
Microstructure Observation ◽  
Heat Treated ◽  
Vacuum Atmosphere ◽  
Different Temperatures ◽  
Press Method

In the present work, monolithic LPS- SiC was fabricated by hot press method with the addition of Al 2 O 3, Y 2 O 3 and SiO 2 and annealed at different temperatures to observe microstructure evolution. Process temperature was varied from 1760°C to 1800°C. Process pressure and maturing time are 20MPa and 1h respectively. Hot pressed samples were cut into rectangular bars. Three-point flexural strength was measured at room temperature in air with a cross-head speed of 0.1 mm/min and a lower span of 18 mm. Flexural strength and elastic modulus measurement was performed using a universal test machine (INSTRON 5581, USA). The apparent density of the sintered body was measured by the Archimedes method. The specimen dimension of the heat treatments is 4 W ×25 L ×1.5 T mm . The specimens used for weight-loss measurement were set into an open carbon crucible to avoid nonuniform temperature distribution within the furnace. Post-fabrication heat treatment was performed in vacuum atmosphere ( PO 2 ≈ 0.01 Pa ). The temperature was increased at a rate of 20 K/min to the heat-treatment temperature and maintained for 10 hours, after which the specimens were furnace cooled. After heat-treatment, weight of heat-treated specimens was carefully measured by an electronic balance. In order to reveal the microstructural change in heat-treated specimen, X-ray diffractometry and microstructure observation were performed and compared with those of the as-fabricated one.

Effect of Atmosphere on Weight Loss in Sintered Silicon Carbide during Heat Treatment

2004 ◽  
Vol 83 (11) ◽  
pp. 2781-2787 ◽  
Author(s):  
Takayuki Nagano ◽  
Kenji Kaneko ◽  
Guo-Dong Zhan ◽  
Mamoru Mitomo
Keyword(s):  
Heat Treatment ◽  
Silicon Carbide ◽  
Weight Loss ◽  
Sintered Silicon
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