ZrB2-SiC ceramics coating for Cf/SiC composites: Microstructure and anti-ablation mechanism

2018 ◽  
Vol 750 ◽  
pp. 857-862 ◽  
Author(s):  
Yang Xiang ◽  
Zhi-hang Peng ◽  
Yi Wang ◽  
Zhong-fang Xing ◽  
Feng Cao
Keyword(s):  
Sic Ceramics ◽  
Ablation Mechanism ◽  
Sic Composites

scholarly journals Pressureless sinterability study of ZrB2–SiC composites containing hexagonal BN and phenolic resin additives

2021 ◽  
Vol 1 (2) ◽  
pp. 99-104
Author(s):  
Iman FarahBakhsh ◽  
Riccarda Antiochia ◽  
Ho Won Jang
Keyword(s):  
Phenolic Resin ◽  
Vacuum Furnace ◽  
Sintering Process ◽  
Powder Mixtures ◽  
Cold Pressing ◽  
X Ray ◽  
Sic Ceramics ◽  
Sic Composites ◽  
By Products

This research is dedicated to the role of different amounts of hexagonal BN (hBN: 0, 1.5, 3, and 4.5 wt%) on the pressureless sinterability of ZrB2–25 vol% SiC ceramics. Phenolic resin (5 wt%) with a carbon yield of ~40 % was incorporated as a binder to the powder mixtures and after initial cold pressing, the final sintering process was performed at 1900 °C for 100 min in a vacuum furnace. The as-sintered specimens were characterized by X-ray diffractometry, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The results disclosed that the incorporation of 1.5 wt% hBN could increase the relative density to ~92%, while the sample with zero hBN content just reached ~81% of full densification. Appropriate hBN content not only facilitated the particle rearrangement during the cold pressing, but also removed the harmful oxide impurities during the final sintering. Nevertheless, the addition of higher amounts of hBN remarkably lessened the densification because of more delamination of the non-reacted hBN flakes and release and entrapment of more gaseous by-products induced by the reacted hBN phases.

Microstructure and ablation mechanism of C/C–SiC composites

2014 ◽  
Vol 34 (2) ◽  
pp. 171-177 ◽  
Author(s):  
Yuanyuan Cui ◽  
Aijun Li ◽  
Bo Li ◽  
Xiao Ma ◽  
Ruicheng Bai ◽  
...  
Keyword(s):  
Ablation Mechanism ◽  
Sic Composites

Effect of the Rare Earth Oxides on Sintering Behavior and Microstructure of ZrB2-SiC Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1740-1742 ◽  
Author(s):  
Xue Ying Li ◽  
Jie Cai Han ◽  
Xing Hong Zhang ◽  
Xiao Guang Luo
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Rare Earth ◽  
Grain Growth ◽  
Rare Earth Oxides ◽  
Sintering Behavior ◽  
Sintering Aids ◽  
Sic Ceramics ◽  
Sic Composites ◽  
And Control

In this study, two rare earth oxides, Y2O3 and La2O3, are used as the additives in the sintering of ZrB2-SiC composites to improve the sinterability and control development of microstructure during densification. The results show that the use of rare earth oxides (5vol.%) improves the powder sinterability, hindered excessive growth of matrix particles and increase fracture toughness of ZrB2-SiC composites, in comparison to ZrB2-SiC with additions free. Nearly full dense materials are obtained by hot pressing at 1900°C. XRD analyses indicate that lanthanum-containing phases were formed in the composite with La2O3. Microstructure observations by SEM reveal that the grain size of ZrB2-SiC with Y2O3 and La2O3 composites are less than the sample without additives, which indicates Y2O3 and La2O3 may restrain the grain growth and increase the fracture toughness. The fracture toughness of ZrB2-SiC composites with Y2O3 and La2O3 reached 5.0MPa·m1/2 and 5.5MPa·m1/2 respectively. Therefore, the additive Y2O3 and La2O3 are very effective as sintering aids for the ZrB2-SiC composite.

TGA CHARACTERISTIC AND FABRICATION OF POROUS SiC CERAMICS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2863-2868
Author(s):  
SEONG HOON KIM ◽  
HAN KI YOON ◽  
SEON JIN KIM ◽  
YI HYUN PARK
Keyword(s):  
Particle Size ◽  
Carbon Fibers ◽  
High Strength ◽  
Porous Ceramics ◽  
Pressing Method ◽  
Sic Ceramics ◽  
Length Direction ◽  
Specific Temperature ◽  
Sic Composites ◽  
Porous Sic

The long-range aim of this research is to develop porous ceramics with high strength, excellent thermal resistance and chemical stability at high temperature in environmental industry. The C f / SiC was made by hot pressing method with SiC powder whose particle size is 50nm and less on the average also Al 2 O 3, Y 2 O 3 and SiO 2 as additive. The carbon fibers of oxidation property are investigated by TGA for finding out decarburization point. As a result, decarburization point selected the specific temperature of TGA curve and the C f/ SiC composites occurred perfectly decarburization at carbon fibers so the clearly porous SiC ceramics were formed many holes of 3-5µm diameters through length direction by its reaction.

Microstructure and ablation mechanism of graphite/SiC composites under oxy-acetylene flame

2014 ◽  
Vol 40 (4) ◽  
pp. 5497-5505 ◽  
Author(s):  
Bingqing Li ◽  
Pengchao Kang ◽  
Huasong Gou ◽  
Gaohui Wu
Keyword(s):  
Ablation Mechanism ◽  
Sic Composites

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.

Microwave Assisted Self-Propagating High-Temperature Synthesis for Joining SiC Ceramics and SiC/SiC Composites by Ni-Al System

2015 ◽  
Vol 727-728 ◽  
pp. 213-218 ◽  
Author(s):  
Shao Hua Han ◽  
Roberto Rosa ◽  
Valentina Casalegno ◽  
Milena Salvo ◽  
Paolo Veronesi ◽  
...  
Keyword(s):  
High Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Chemical Vapor ◽  
Atomic Ratio ◽  
Temperature Synthesis ◽  
Sic Ceramics ◽  
High Temperature Synthesis ◽  
Interface Bond Strength ◽  
Cte Mismatch ◽  
Sic Composites

Microwave has been applied to ignite the Self-propagating High-temperature Synthesis (SHS) of compacted Ni-Al mixtures, having 1:1 atomic ratio, in order to join Chemical Vapor Deposition (CVD) SiC ceramics and SiC/SiC composites. The average joint thickness of CVD SiC joint is about 200 μm and the Coefficient of Thermal Expansion (CTE) mismatch between CVD SiC and Ni-Al intermetallic compounds results in a interface bond strength inferior to that of the substrate and joining material; on the other hand, for the SiC/SiC composite joints, as a result of the porosity of SiC/SiC composites, the SHS products readily infiltrated into the pore spaces of the composite, leading to an increased porosity of the joint area and a better lower interface than the upper one. The mechanical strength of the joints has been evaluated by Single-Lap (SL) shear test at room temperature; neither of the ceramic joints nor the composites joint gave satisfactory results, but the ceramic joints reaching a maximum shear strength value of 56MPa exhibited a positive aspect for further experiments.

Preparation of Cf/SiC Composites by Chemical Liquid-Vapor Deposition Process

2012 ◽  
Vol 512-515 ◽  
pp. 804-807
Author(s):  
Min Mei ◽  
Xin Bo He ◽  
Xuan Hui Qu ◽  
Hai Feng Hu ◽  
Yu Di Zhang ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Vapor Deposition ◽  
Fracture Behavior ◽  
Deposition Process ◽  
Xrd Pattern ◽  
Sic Ceramics ◽  
The Matrix ◽  
Sic Composites ◽  
Load Deflection Curve ◽  
Liquid Vapor

The conversion of the liquid polycabosilane (LPCS) into silicon carbide was investigated by IR, XRD, which indicated the feasibility of the transition from LPCS to SiC ceramics above 900°C. The FTIR spectra and XRD Pattern of the Cf/SiC composites show that the matrix deposited at 1200°C has silicon carbide structure with the crystallite size of β-SiC phase of about 41 nm, while the SiC phase is amorphous at 900°C. The carbon fiber reinforced silicon carbide composites (Cf/SiC) were hereby prepared at 900°C and 1200°C, through chemical liquid-vapor deposition (CLVD) process using LPCS as precursor. Flexural strength of 224 MPa for Cf/SiC specimen with density of 1.81g·cm-3was obtained after being prepared at 1200°C for 30 minutes. The load-deflection curve has shown that the fracture behavior of the Cf/SiC composites is a typical non-brittleness. The results indicate that the CLVD process has a great advantage and prospect to prepare Cf/SiC composites in future.

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