Morphological description of coating cracks in SiC coated carbon-carbon composites

Yurgartis, S.W.; Bush, M.D.; Mast, Bram

doi:10.1016/0257-8972(94)90084-1

Cited by 16 publications

(4 citation statements)

References 9 publications

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“…After validating the model with the simulated craze cracks, we focus on specimens with natural craze cracks. The crack patterns in the specimens are characterized according to crack spacing, crack widths, and crack depths, with methods similar to those of Yurgartis et al (7). Corrections are applied for the thermal contraction of the cracks and oxidation of the crack walls is considered.…”

Section: Donald Currymentioning

confidence: 99%

Oxidation of Carbon/Carbon through Coating Cracks

Jacobson,

Roth,

Rauser

et al. 2008

Meet. Abstr.

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Reinforced carbon/carbon (RCC) is used to protect the wing leading edge and nose cap of the Space Shuttle Orbiter on re-entry. It is composed of a lay-up of carbon/carbon fabric protected by a SiC conversion coating. Due to the thermal expansion mismatch of the carbon/carbon and the SiC, the SiC cracks on cool-down from the processing temperature. The cracks act as pathways for oxidation of the carbon/carbon. A model for the diffusion controlled oxidation of carbon/carbon through machined slots and cracks is developed and compared to laboratory experiments. A symmetric cylindrical oxidation cavity develops under the slots, confirming diffusion control. Comparison of cross sectional dimensions as a function of oxidation time shows good agreement with the model. A second set of oxidation experiments was done with samples with only the natural craze cracks, using weight loss as an index of oxidation. The agreement of these rates with the model is quite reasonable.

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Section: Donald Currymentioning

confidence: 99%

Oxidation of Carbon/Carbon through Coating Cracks

Jacobson,

Roth,

Rauser

et al. 2008

Meet. Abstr.

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“…To improve the oxidation resistance of C /Cs, various heat resistant ceramic coatings have been studied [2,3], in particular, SiC and Si 3 N 4 . However, due to the extremely low coefficient of thermal expansion of C /C composites [4], thermal mismatch strain between the coating and C /C substrate often leads to coating cracks [3,5], and oxygen diffusion through these cracks results in substrate oxidation [2,3,[6][7][8][9]. Thus, the most important matter for the improvement of oxidation resistance of C /C composite is to suppress or at least to minimize the coating cracks.…”

Section: Introductionmentioning

confidence: 99%

Suppression of through-the-thickness cracks in SiC coating on C/C composites

Hatta¹,

Aoki²,

Hitomi³

et al. 2000

Composite Interfaces

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Two concepts are proposed to minimize coating cracks on the surface of C/ C composites. The first idea of a multi-layered coating is based on the phenomenon that there exists a critical coating thickness below which no coating cracks appear. This phenomenon is experimentally and theoretically confirmed for a SiC coating. Thus, by alternately laminating thin SiC and carbon layers, coatingcracking is expected to be suppressed for a thick and dense coating.The second concept is the use of a fiber-reinforced coating. By the fiber reinforcement, the toughness of a ceramic coating should be improved. In this paper, both concepts are shown to be promising to reduce through-the-thickness coating cracks. In addition, problems especially related to oxidation behavior are discussed in relation with the two-coating systems.

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“…His worked was tested and proved success in numerous applications. Yurgartis et al 6 worked on measuring possible descriptions of numerous crack coatings like types of cracks, their width, orientation, area of cell, and gaps amidst them. Ma et al 7 utilized the method of hardness indentation along with scratch tests on a fractured cross-sectional piece of specimen.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of uncoated, single layer, and multilayer-coated TiAlN/TiN tool inserts in dry orthogonal cutting of AISI/SAE 4140 alloy steel

Akbar

Arsalan

2023

Proceedings of the Institution of Mechanical Engineers, Part B:

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Significant temperature rise is stimulated during high-speed machining of metals, specifically in dry cutting conditions. This experimental investigation undertakes the effects of uncoated, single layer coatings (TiN and TiAlN), and multilayer coatings [TiAlN/TiN (9 + 5 µm), (9 + 3 µm), (9 + 1 µm), and (5 + 1 µm)] on cutting tool material during dry orthogonal cutting of AISI/SAE 4140 alloy steel. The study compares crucial parameters such as cutting and feed forces, chip-tool contact area, thickness of deformed chip, chip reduction coefficient, heat partition ratio, flank wear, and shear angle. The layer TiAlN used as the first layer from the Tungsten Carbide (WC) substrate owing to its better adhesion property, whereas TiN used as the second layer (top coating) owing to its better sliding behavior. In this research, cutting operations have carried out using Dean Smith and Grace Lathe machine. A Scanning Electron Microscope (SEM) also used along with a Kistler 9263 dynamometer to measure cutting forces. The cutting temperatures are measured with the help of an infrared, high-resolution thermal imaging camera, ThermaCAM model SC3000 by FLIR. Results have shown that layers act as a thermal barrier that block excessive heat generation in the cutting tool. Thus, this increasing the surface finish, tool life, and overall efficiency, while reducing the abrasive wear, tear, and parallel ridges due to rubbing friction. Furthermore, it has found that multilayer coating of (9 + 5 = 14 µm) shown good consistent results with less variance, specifically in the high-speed machining regions. Hence, the study evidently justifies the usage of coated tool inserts in high-speed dry cutting operations.

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Morphological description of coating cracks in SiC coated carbon-carbon composites

Cited by 16 publications

References 9 publications

Oxidation of Carbon/Carbon through Coating Cracks

Oxidation of Carbon/Carbon through Coating Cracks

Suppression of through-the-thickness cracks in SiC coating on C/C composites

Experimental investigation of uncoated, single layer, and multilayer-coated TiAlN/TiN tool inserts in dry orthogonal cutting of AISI/SAE 4140 alloy steel

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