Author: Michael C. Halbig
Publisher:
ISBN:
Category :
Languages : en
Pages : 18
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Book Description
Carbon fiber reinforced silicon carbide matrix composites (C/SiC) are a ceramic matrix composite (CMC) material that offers benefits for use in a wide range of high temperature structural applications. However the susceptibility of the carbon fibers to degradation in oxidizing environments has hindered the material's use in certain applications requiring long lives under oxidizing conditions. The susceptibility of carbon fibers to oxidation will be discussed as well as the enhancement (improvement in oxidation resistance) of C/SiC materials. Thermogravimetric analysis of carbon fibers shows susceptibility to oxidation in two distinct kinetic regimes. However, in the thermogravimetric (wt. loss) analysis of unstressed, unenhanced, seal coated C/SiC coupons, the two regimes were not observed due to crack closure and matrix effects, which inhibited the oxidation process. Stressed oxidation (creep rupture) tests put the material under a stress, which is a more realistic condition for many applications. In stressed oxidation tests, the two oxidation kinetics regimes were observed. These tests can provide better insight into how the material will perform in applications involving stress. Stressed oxidation of enhanced materials containing oxidation inhibitors showed significantly improved lives at the specific test conditions considered, although there was susceptibility to oxidation at intermediate temperatures.
Author:
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ISBN:
Category :
Languages : en
Pages :
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 22
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Book Description
Ten different ceramic matrix composite (CMC) materials were subjected to a constant load and temperature in an air environment. Tests conducted under these conditions are often referred to as stressed oxidation or creep rupture tests. The stressed oxidation tests were conducted at a temperature of 1454 deg C at stresses of 69 MPa, 172 MPa and 50% of each material's ultimate tensile strength. The ten materials included such CMCs as C/SiC, SiC/C, SiC/SiC, SiC/SiNC and C/C. The time to failure results of the stressed oxidation tests will be presented. Much of the discussion regarding material degradation under stressed oxidation conditions will focus on C/SiC composites. Thermogravimetric analysis of the oxidation of fully exposed carbon fiber (T300) and of C/SiC coupons will be presented as well as a model that predicts the oxidation patterns and kinetics of carbon fiber tows oxidizing in a nonreactive matrix.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 156
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Author:
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ISBN:
Category :
Languages : en
Pages : 14
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Book Description
Author: Edgar Lara-Curzio
Publisher: John Wiley & Sons
ISBN: 0470291583
Category : Technology & Engineering
Languages : en
Pages : 653
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Book Description
A collection of Papers Presented at the 28th International Conference and Exposition on Advanced Ceramics and Composites held in conjunction with the 8th International Symposium on Ceramics in Energy Storage and Power Conversion Systems.
Author: Mrityunjay Singh
Publisher: John Wiley & Sons
ISBN: 0470295147
Category : Technology & Engineering
Languages : en
Pages : 746
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Book Description
This volume is part of the Ceramic Engineering and Science Proceeding (CESP) series. This series contains a collection of papers dealing with issues in both traditional ceramics (i.e., glass, whitewares, refractories, and porcelain enamel) and advanced ceramics. Topics covered in the area of advanced ceramic include bioceramics, nanomaterials, composites, solid oxide fuel cells, mechanical properties and structural design, advanced ceramic coatings, ceramic armor, porous ceramics, and more.
Author: Hua-Tay Lin
Publisher: John Wiley & Sons
ISBN: 0470295198
Category : Technology & Engineering
Languages : en
Pages : 872
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Book Description
This volume is part of the Ceramic Engineering and Science Proceeding (CESP) series. This series contains a collection of papers dealing with issues in both traditional ceramics (i.e., glass, whitewares, refractories, and porcelain enamel) and advanced ceramics. Topics covered in the area of advanced ceramic include bioceramics, nanomaterials, composites, solid oxide fuel cells, mechanical properties and structural design, advanced ceramic coatings, ceramic armor, porous ceramics, and more.
Author: Michael C. Halbig
Publisher:
ISBN:
Category :
Languages : en
Pages : 14
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Book Description
A finite difference model has been developed and was used to study the oxidation kinetics of carbon fibers exposed by the presence of a through-thickness matrix crack in a ceramic matrix composite. Air was the environment of interest so that the model could be compared to experimental testing. The limiting steps of diffusion controlled and reaction controlled kinetics were investigated by changing the value of the simulated temperature which, in turn corresponds to a change in the diffusion coefficient and reaction rate constant. The reaction rates for the oxidation of carbon fibers were compared to theoretical values and oxidation trends predicted by the model were compared to experimental trends.
