A study on zoning coating method of absorbing materials for stealth aircraft

Lu, Shaoze; Huang, Jun; Song, Lei; Yi, Mingxu

doi:10.1016/j.ijleo.2019.163912

Cited by 13 publications

(7 citation statements)

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“…TBCs with thicker coatings have greater thermal insulation. Therefore, thick TBCs have various applications in engineering-for example, they are essential for radar absorption [55,62]. However, in our previous study [53], thick TBCs often have a greater crack-driving force and stress due to the thermal mismatch strain between coating and substrate at the tip of the crack.…”

Section: Discussionmentioning

confidence: 80%

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Tailoring Periodic Vertical Cracks in Thermal Barrier Coatings Enabling High Strain Tolerance

Mehboob

et al. 2021

Coatings

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Lifetime is a basic support for the thermal insulation function of thermal barrier coatings (TBCs). Therefore, extending the life span is essential to develop next-generation TBCs. For this objective, the columnar structure formed by vertical cracks appears to make sense. However, the underlying mechanism is still unclear. This work scrutinizes the influence of periodic vertical cracks on cracking behavior in order to tailor high strain tolerant TBCs. A finite element model was evolved to explore the crack behavior influenced by thermal mismatch strain between substrate and coating. The virtual crack closure technique (VCCT) was used to describe the propagation of crack under load. It is found clearly that the space between two vertical cracks (short for SVC) along the in-plane direction has a noteworthy influence on the strain tolerance of TBCs. Results indicate that the strain energy release rate (SERR) and stresses at the pre-crack tip increase continuously with the increase of the SVC, suggesting that the driving force for cracks is increasing. The crack is not propagated when the SVC is very small, whereas the crack grows continuously with the increase of the SVC. The growth of a crack can be prevented by reducing the SVC. A critical value for the SVC was found. When the SVC is less than the critical value, the SERR can be dramatically reduced. Thus, the SVC of periodic cracks can be tailored to obtain TBCs with high strain tolerance.

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Section: Discussionmentioning

confidence: 80%

“…TBCs with thicker coatings have greater thermal insulation. Therefo have various applications in engineering-for example, they are essentia sorption [55,62]. However, in our previous study [53], thick TBCs often Figure 9 represents the variation of crack length in the ceramic top-coat with the SVC.…”

Section: Tc Crack Growthmentioning

confidence: 96%

Tailoring Periodic Vertical Cracks in Thermal Barrier Coatings Enabling High Strain Tolerance

Mehboob

et al. 2021

Coatings

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“…For TBCs, a thicker coating means larger thermal insulation, and a thicker coating is necessary for radar absorbing. Therefore, thick coatings have wide applications in engineering [69,78]. However, based on our investigation, a larger thickness often refers to a larger SERR at crack tip.…”

Section: Strain Tolerant Design For Thick Coatingsmentioning

confidence: 80%

Strain-Induced Cracking Behavior of Coating/Substrate Systems and Strain Tolerant Design for Thick Coatings

Mehboob

et al. 2020

Coatings

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The life span for a coating attached to its substrate is basic support for their desired protective function. Therefore, it is necessary to find out the causes responsible for the failure of coatings during service. This paper developed a finite element model to investigate the cracking behavior of plasma-sprayed ceramic coatings induced by the mismatch strain of thermal expansion between coating and substrate. Crack propagation affected by coating thicknesses was realized by the virtual crack closure technique (VCCT). The residual stresses (σ22 and σ12) and the strain energy release rate (SERR) induced at the tip of pre-crack in ceramic coatings are calculated. Results show that the σ22 and σ12 at the tip of the pre-crack increases continuously with the thickening ceramic coatings. The SERRs at the tip of the pre-crack in top-coat (TC) were increased with the thickness of ceramic coatings, resulting in the propagation of cracks. The crack length increases with the thickening of ceramic coatings. The crack propagation and coalescence lead to coating spallation, which is one of the main failure modes for plasma sprayed ceramic coatings during service. Given that, strain tolerant design was developed by inserting vertical pores in coatings. It was found that the SERRs were decreased with the increase in the number of vertical pores, as well as their depth. Moreover, the coatings with vertical pores appear to be crack-resistant, in particular for the thicker coatings. This suggests that the strain tolerant design is helpful to extend the life span of thick coatings, which makes a fundamental contribution to the design and preparation of advanced protective coatings in future applications.

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“…With the rapid development of modern science and technology, the emergence of electronic equipment has brought convenience to everyday life but poses a threat to the environment. − Therefore, the realization of efficient electromagnetic wave-absorbing materials that can safely convert electromagnetic energy into heat energy or other forms of energy has become the focus of research in recent years and has broad application prospects in military equipment, medical instruments, and daily life. , Generally speaking, traditional single-absorbing materials, such as dielectric ceramics, ferrites, conductive polymers, and magnetic metals, have the shortcomings of a large thickness and a narrow absorption band. In order to improve these problems, researchers have combined magnetic loss-type, dielectric loss-type, and conductive loss-type materials to enhance the absorption performance of materials.…”

Section: Introductionmentioning

confidence: 99%

Sulfur-Doped MXene-Based Nanocomposites for Efficient Electromagnetic Wave Absorbers via Polarization and Magnetization

Zhang

Liu

Wang

et al. 2023

ACS Appl. Nano Mater.

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Ti 3 C 2 T x (MXene) materials with multilayered structures have been widely investigated as promising absorption materials. However, the electromagnetic wave absorption performance of a single Ti 3 C 2 T x MXene has always been limited by interface mismatches due to high reflectivity. In this work, sulfur-doped MXene-based nanocomposites were constructed by a mild doping and calcination method and performance was regulated by manipulating chemical composition, loading ratio, electromagnetic parameters, or impedance matching. Here, sulfur-doped MXene and titanium dioxide produced via hightemperature calcination (S-MXene (TiO 2 )) provided abundant defects and functional groups, resulting in dipole polarization relaxation. The introduction of Ag improved the electrical conductivity, and the CoNi alloy could enhance the magnetic loss and improve impedance matching. The electromagnetic wave absorption ability was enhanced thanks to the combined effects of suitable conductivity, dipole polarization, interface polarization, and magnetic loss. The S-MXene (TiO 2 )/Ag/CoNi nanocomposites exhibited a high reflection loss of −63.1 dB at a thickness of 2.1 mm and a wide effective absorption bandwidth of 5.2 GHz at a thickness of 2.0 mm. Moreover, by adjusting the mass ratio of nanocomposites' components, the minimum reflection loss value was up to −80.9 dB at only 1.5 mm. This mechanism of increasing material loss through doping is of great significance for improving the electromagnetic wave absorption of MXene-based nanocomposites.

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A study on zoning coating method of absorbing materials for stealth aircraft

Cited by 13 publications

References 0 publications

Tailoring Periodic Vertical Cracks in Thermal Barrier Coatings Enabling High Strain Tolerance

Tailoring Periodic Vertical Cracks in Thermal Barrier Coatings Enabling High Strain Tolerance

Strain-Induced Cracking Behavior of Coating/Substrate Systems and Strain Tolerant Design for Thick Coatings

Sulfur-Doped MXene-Based Nanocomposites for Efficient Electromagnetic Wave Absorbers via Polarization and Magnetization

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