scholarly journals Microstructural regulation, oxidation resistance, and mechanical properties of Cf/SiC/SiHfBOC composites prepared by chemical vapor infiltration with precursor infiltration pyrolysis

2021 ◽  
Author(s):  
Yang Lyu ◽  
Baihe Du ◽  
Guiqing Chen ◽  
Guangdong Zhao ◽  
Yuan Cheng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Oxidation Resistance ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Oxidation Products ◽  
Weight Retention ◽  
Composite Surface ◽  
Before And After ◽  
Oxidation In Air ◽  
Vapor Infiltration

AbstractTo further improve the oxidation resistance of polymer derived ceramic (PDC) composites in harsh environments, Cf/SiC/SiHfBOC composites were prepared by chemical vapor infiltration (CVI) and precursor impregnation pyrolysis (PIP) methods. The weight retention change, mechanical properties, and microstructure of Cf/SiC/SiHfBOC before and after oxidation in air were studied in details. Microscopic analyses showed that only the interface between the ceramics and fibers was oxidized to some extent, and hafnium had been enriched on the composite surface after oxidizing at different temperature. The main oxidation products of Cf/SiC/SiHfBOC composites were HfO2 and HfSiO4 after oxidation at 1500 °C for 60 min. Moreover, the weight retention ratio and compressive strength of the Cf/SiC/SiHfBOC composites are 83.97% and 23.88±3.11 MPa, respectively. It indicates that the Cf/SiC/SiHfBOC composites should be promising to be used for a short time in the oxidation environment at 1500 °C.

scholarly journals Microstructural Regulation, Oxidation Resistance and Mechanical Properties of Cf/SiC/SiHfBOC Composites Prepared By Chemical Vapor Infiltration With Precursor Infiltration Pyrolysis

2021 ◽  
Author(s):  
Yang LYU ◽  
Baihe DU ◽  
Guiqing CHEN ◽  
Guangdong ZHAO ◽  
Yuan CHENG ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Oxidation Resistance ◽  
Microscopic Analysis ◽  
Chemical Vapor ◽  
Ceramic Composites ◽  
Chemical Vapor Infiltration ◽  
Weight Retention ◽  
Composite Surface ◽  
Before And After ◽  
Vapor Infiltration

Abstract To further improve the oxidation resistance of PDC (Polymer Derived Ceramic) composites in harsh environments, Cf/SiC/SiHfBOC composites were prepared by CVI (Chemical Vapor Infiltration) and PIP (Precursor Impregnation Pyrolysis) methods. The weight retention change, mechanical properties, and microstructure of Cf/SiC/SiHfBOC before and after oxidation in air were studied in detail. Microscopic analysis showed that only the interface between the ceramic and fibers were oxidized to some extent and hafnium had been enriched on the composite surface, after oxidation at different oxidation environments. After Cf/SiC/SiHfBOC composites oxidized at 1500 ℃ for 60 min, it was mainly determined by the HfO2 and HfSiO4 phase. Moreover, the weight retention ratio and compressive strength of the Cf/SiC/SiHfBOC composites are 83.97 % and 23.88 ± 3.11 MPa, respectively. It indicates that the Cf/SiC/SiHfBOC composites can be used for a long time in the oxidation environment at 1500 ℃.

Effects of chemical vapor infiltration atmosphere on the mechanical properties and microstructure of carbon fibers

2001 ◽  
Vol 21 (6) ◽  
pp. 809-816 ◽  
Author(s):  
Yongdong Xu ◽  
Laifei Cheng ◽  
Litong Zhang ◽  
Hongfeng Yin ◽  
Xiaowei Yin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibers ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Vapor Infiltration

Chemical vapor infiltration of SiC with microwave heating

1993 ◽  
Vol 8 (5) ◽  
pp. 1057-1067 ◽  
Author(s):  
José I. Morell ◽  
Demetre J. Economou ◽  
Neal R. Amundson
Keyword(s):  
Microwave Heating ◽  
Processing Time ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Chemical System ◽  
Gaseous Species ◽  
Composite Surface ◽  
Transport Reaction ◽  
Accessible Porosity ◽  
Vapor Infiltration

A mathematical model was developed to elucidate the interaction between transport/reaction processes and the evolution of porosity in chemical vapor infiltration with microwave heating (MCVI). The analysis included a set of partial differential equations describing the spatiotemporal variation of gaseous species concentration, composite temperature, porosity, and stress. Maxwell's equations were used to determine the distribution of power dissipated inside the composite. The deposition of silicon carbide was selected as a model chemical system to explore the general features of MCVI. MCVI can provide a favorable temperature distribution in the composite yielding an inside-out deposition pattern, thereby preventing entrapment of accessible porosity. For this temperature profile, tensile stresses develop at the outer regions and compressive stresses are found in the composite core. For a given system there exists a minimum value of the coefficient for heat transfer from the composite surface, h, below which accessible porosity is trapped within the composite. Similarly, there exists a maximum value of the incident microwave energy flux, I0, above which accessible porosity is trapped within the composite. I0 and h can be optimized for a given preform to achieve complete densification with minimum processing time. Using the technique of pulsed-power, the processing time can be reduced even further without compromising density uniformity. Power dissipation profiles in the composite depend strongly on preform thickness, microwave frequency, and relative loss factor.

Microstructure Characterisation and Mechanical Behaviour of 2D C/SiC-C Composite with SiC/PyC Multilayer Matrix

2011 ◽  
Vol 194-196 ◽  
pp. 1789-1792
Author(s):  
Zhi Xin Meng ◽  
Lai Fei Cheng ◽  
Qiao Mu Liu ◽  
Xiu Feng Han ◽  
Li Tong Zhang
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behaviour ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Mechanical Behaviors ◽  
Successive Extraction ◽  
The Matrix ◽  
Vapor Infiltration

Two composites of 2D C/SiC-C and 2D C/SiC were fabricated by isothermal-isobaric chemical vapor infiltration (ICVI). The microstructures and mechanical behaviors at room temperature were characterized and investigated, respectively. In the 2D C/SiC-C composite, the PyC matrix layers are homogeneous and continuous. Moreover, the matrix layers of SiC and PyC bond well and almost no microcracks are found in the multilayered matrix. Compared with the 2D C/SiC composite, the 2D C/SiC-C composite exihibits improved mechanical properties.The successive extraction of matrix layers and multiple deflections of cracks in the SiC/PyC multilayered matrix contribute to the improvement of mechanical properties.

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