Determining Elastic Modulus of Ceramic Coatings at Elevated Temperature Using Impulse Excitation Technology

2016 ◽  
Vol 680 ◽  
pp. 13-16 ◽  
Author(s):  
Chen Guang Wei ◽  
Yi Wang Bao ◽  
Xue Qiang Cao ◽  
Zhao Liu ◽  
Yuan Tian
Keyword(s):  
Elastic Modulus ◽  
Elevated Temperature ◽  
Single Layer ◽  
Ceramic Coatings ◽  
Coated Sample ◽  
Multilayer Coatings ◽  
Relative Method ◽  
Impulse Excitation ◽  
Novel Method ◽  
Layer Coating

Although elastic modulus of ceramic coatings at elevated temperature is difficult to measure, it was evaluated in this work simply by impulse excitation tests based on the relative method that need only the measured moduli of coated sample and substrate. This novel method was demonstrated to be valid not only for the single layer coating but also for multilayer coatings.

Evaluating Thermal Expansion Coefficient of SiC Coatings by Relative Method

2017 ◽  
Vol 726 ◽  
pp. 110-114
Author(s):  
Rui Na Pan ◽  
Chen Guang Wei ◽  
Yi Wang Bao ◽  
De Tian Wan ◽  
Yan Ping Wang
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Ceramic Coatings ◽  
Test Method ◽  
Experimental Results ◽  
Simple Test ◽  
Relative Method ◽  
Novel Method ◽  
Sic Coatings

A simple test approach named relative method is developed for determining the thermal expansion coefficient of ceramic coatings. Although ceramic coatings are hardly separated from the substrates, it was evaluated in this work simply by need only the measured thermal expansion coefficient of coated samples and substrates. This novel method was demonstrated to be valid for rectangular beam samples of two types of coating configurations: sandwich coating and around coating. The feasibility of this test method was confirmed by experimental results of SiC coating.

scholarly journals Evaluating high temperature elastic modulus of ceramic coatings by relative method

2017 ◽  
Vol 6 (4) ◽  
pp. 288-303 ◽  
Author(s):  
Guanglin Nie ◽  
Yiwang Bao ◽  
Detian Wan ◽  
Yuan Tian
Keyword(s):  
Elastic Modulus ◽  
High Temperature ◽  
Ceramic Coatings ◽  
Relative Method

Architecture of Functionally Graded Ceramic Coatings Against Surface Thermal Fracture

1996 ◽  
Vol 118 (4) ◽  
pp. 522-528 ◽  
Author(s):  
B. D. Choules ◽  
K. Kokini
Keyword(s):  
Stress Relaxation ◽  
Thermal Fatigue ◽  
Thermal Protection ◽  
Fatigue Behavior ◽  
Multilayer Coating ◽  
Single Layer ◽  
Ceramic Coatings ◽  
Functionally Graded ◽  
Transient Temperature ◽  
Layer Coating

An analytical study was performed to study the effect of architecture on the initiation of surface cracking in multilayer ceramic coatings. Two modes of crack initiation were considered: 1) tension resulting from stress relaxation, and 2) cyclic thermal fatigue. Transient temperature distributions were determined using a finite difference technique, and stress distributions were calculated using a multilayer beam theory. The results showed that as more layers were added and as the ceramic coating became thinner, lower maximum surface stresses resulted during cooling after stress relaxation. Also, a thick eight layer coating had similar thermal fatigue behavior to a thin single layer coating. It was determined that a thick multilayer coating adds a significant amount of thermal protection when compared to a thin single layered coating.

Measurement of the High Temperature Elastic Modulus of Alumina Ceramics by Different Testing Methods

2018 ◽  
Vol 768 ◽  
pp. 24-30
Author(s):  
Guang Lin Nie ◽  
Yi Wang Bao ◽  
De Tian Wan ◽  
Yuan Tian
Keyword(s):  
Elastic Modulus ◽  
High Temperature ◽  
Dynamic Method ◽  
Vibration Signal ◽  
Bending Test ◽  
Relative Method ◽  
Alumina Ceramics ◽  
Static Tests ◽  
Four Point Bending ◽  
Impulse Excitation

Alumina ceramics are widely used in the demanding high temperature applications in which the high temperature elastic moduli (EHT) is a key property for their reliability and safety. In this paper, the elastic modulus of alumina was determined by dynamic method (impulse excitation technique) and static tests (three-point bending test and four-point bending test). For the static tests, the relative method was applied to determine the accurate deflection measurement in the heating furnace. The measured results revealed that the modulus of alumina slowly decreased from RT to 1000 °C and rapidly decreased with the increasing temperatures from 1000 °C to 1300°C. The EHT evaluated by dynamic method were higher than that tested by static tests with the reason of that impulse excitation technique only applied small forces onto a sample such that defects activity is negligible. Also the resonant frequencies couldn’t be measured easily at high temperature, because the vibration signal emitted by the sample was weak. The static approaches combined with relative method were beyond the limit to high temperatures, and they can be also used to evaluate the ultra-high temperature modulus.

Evaluating Absolute Hardness of Ceramic Coatings Using Relative Method

2010 ◽  
Vol 434-435 ◽  
pp. 530-533
Author(s):  
Kun Ming Li ◽  
Yi Wang Bao ◽  
De Tian Wan ◽  
Yan Qiu ◽  
Li Tian ◽  
...  
Keyword(s):  
Steel Substrate ◽  
Ceramic Coatings ◽  
Coated Sample ◽  
Relative Method ◽  
New Model ◽  
Indentation Tests ◽  
The Mean ◽  
Composite Hardness ◽  
Substrate Hardness ◽  
The Relationship

Micro-hardness measurements of thin coatings have to face the problem of the influence of the substrate. Based on relative method and the relationship between the composite hardness (the hardness of the coated sample) and the substrate hardness, a new model is proposed to evaluate the absolute hardness of ceramic coatings. Indentation tests with various load levels were carried out with specimens of (Ti,Al)xN1-x/SiyN1-y composite coating on SKH51 steel substrate. The results were analyzed by the new model and compared with those calculated by J-H (Jönsson and Hogmark) and L-C (Lesage and Chicot) models. The mean coating hardness obtained from this model shows similar results with the J-H model but a little higher than that from L-C model.

scholarly journals Homogeneous 2D and 3D alignment of cardiomyocyte in dilated cardiomyopathy revealed by intravital heart imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kiyoshi Masuyama ◽  
Tomoaki Higo ◽  
Jong-Kook Lee ◽  
Ryohei Matsuura ◽  
Ian Jones ◽  
...  
Keyword(s):  
Heart Failure ◽  
Dilated Cardiomyopathy ◽  
Cardiac Dysfunction ◽  
Three Dimensional ◽  
Single Layer ◽  
Specific Pattern ◽  
Two Dimensional ◽  
Heart Imaging ◽  
Novel Method ◽  
2D And 3D

AbstractIn contrast to hypertrophic cardiomyopathy, there has been reported no specific pattern of cardiomyocyte array in dilated cardiomyopathy (DCM), partially because lack of alignment assessment in a three-dimensional (3D) manner. Here we have established a novel method to evaluate cardiomyocyte alignment in 3D using intravital heart imaging and demonstrated homogeneous alignment in DCM mice. Whilst cardiomyocytes of control mice changed their alignment by every layer in 3D and position twistedly even in a single layer, termed myocyte twist, cardiomyocytes of DCM mice aligned homogeneously both in two-dimensional (2D) and in 3D and lost myocyte twist. Manipulation of cultured cardiomyocyte toward homogeneously aligned increased their contractility, suggesting that homogeneous alignment in DCM mice is due to a sort of alignment remodelling as a way to compensate cardiac dysfunction. Our findings provide the first intravital evidence of cardiomyocyte alignment and will bring new insights into understanding the mechanism of heart failure.

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