Comparison of the thermal stresses developed in diamond and advanced ceramic coating systems under thermal loading

Abstract:The accurate evaluation of the elastic modulus of ceramic coatings at high temperature (HT) is of high significance for industrial application, yet it is not easy to get the practical modulus at HT due to the difficulty of the deformation measurement and coating separation from the composite samples. This work presented a simple approach in which relative method was used twice to solve this problem indirectly. Given a single-face or double-face coated beam sample, the relative method was firstly used to determine the real mid-span deflection of the three-point bending piece at HT, and secondly to derive the analytical relation among the HT moduli of the coating, the coated and uncoated samples. Thus the HT modulus of the coatings on beam samples is determined uniquely via the measured HT moduli of the samples with and without coatings. For a ring sample (from tube with outer-side, inner-side, and double-side coating), the relative method was used firstly to determine the real compression deformation of a split ring sample at HT, secondly to derive the relationship among the slope of load-deformation curve of the coated ring, the HT modulus of the coating and substrate. Thus, the HT modulus of ceramic coatings can be evaluated by the substrate modulus and the load-deformation data of coated rings. Mathematic expressions of those calculations were derived for the beam and ring samples. CVD-SiC coatings on graphite substrate were selected as the testing samples, of which the measured modulus ranging from room temperature to 2100 ℃ demonstrated the validity and convenience of the relative method.

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“…1. Two displacements of the cross-beam, 1 f  and 2 f  , will be obtained for the test sample ( Fig. 1(a)) and the reference sample ( Fig.…”

Section: Determining Ht Elastic Modulus Of Coatings On Beam Samplesmentioning

confidence: 99%

“…Ceramic coatings have attracted considerable attention of material scientists and mechanical engineers due to their wide applications in aerospace, aviation, energy, petrochemical, and chemical industry fields to withstand high temperature (HT) [1][2][3]. The HT ceramic coatings are used for three main functions, viz.…”

Section: Introductionmentioning

confidence: 99%

Evaluating high temperature elastic modulus of ceramic coatings by relative method

et al. 2017

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“…As the deposition temperature can reach about 950°C before the cooling process in the diamond film deposition, deposition temperature at the edge of the diamond film was set as 950°C and a radial temperature gradient of 50°C from the edge to the centre was introduced during the simulation. An ANSYS thermal analysis was carried out to calculate the temperature distribution in the model and then the whole model was cooled to room temperature using a heat transfer coefficient of 30 W/(m 2 ·K) [7]. At the same time, a coupled structural-thermal analysis was performed to compute the thermal stress distribution.…”

Section: Experimental Procedures and Finite Element Modelmentioning

confidence: 99%

“…Recently, numerical methods e.g. finite element analysis, have been accepted as attractive tools to simulate the thermal stress in coating substrate systems [5][6][7][8][9]. It is generally acknowledged that the interlayer between the diamond film and the substrate is used to enhance the adhesion of the film to substrates, reduce the thermal mismatch between them, and prevent the film from cracking [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Deposition of crackless freestanding diamond films on Mo substrates with Zr interlayer

Liu

Chen

et al. 2010

Int J Miner Metall Mater

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The Mo substrate with Zr interlayer, namely composite substrate, was employed to solve the problem of crack formation in the freestanding diamond film deposition. Freestanding diamond films deposited on the composite substrates by the direct current arc plasma jet chemical vapor deposition (CVD) method were investigated with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy. In addition, the stress distribution during the large area freestanding diamond film deposition on the composite substrate was analyzed based on the finite element model ANSYS. The results reveal that Zr interlayer can be easily destroyed during the post-deposition cooling process, which is helpful for stress release and crack avoiding in diamond films.

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“…Compared with regular polymer, CNTs have lower expansion coefficient, which reduces the residual stress in laminated polymer composites. Previous studies have reported that the magnitude and distribution of thermal residual stress can be adjusted by selecting the appropriate material combination and controlling the compositional gradient [4,5]. In addition, CNTs have favorable strength and stiffness and is capable of changing material properties such as electrical and thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

Optimizing the manufacturing parameters of carbon nanotubes stiffened speaker diaphragm using Taguchi method

Lai

2016

Applied Acoustics

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Comparison of the thermal stresses developed in diamond and advanced ceramic coating systems under thermal loading

Cited by 21 publications

References 11 publications

Evaluating high temperature elastic modulus of ceramic coatings by relative method

Evaluating high temperature elastic modulus of ceramic coatings by relative method

Deposition of crackless freestanding diamond films on Mo substrates with Zr interlayer

Optimizing the manufacturing parameters of carbon nanotubes stiffened speaker diaphragm using Taguchi method

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