Effects of coating thickness and residual stresses on the bond strength of ASTM C633-79 thermal spray coating test specimens

1994 ◽  
Vol 3 (4) ◽  
pp. 371-378 ◽  
Author(s):  
D. J. Greving ◽  
J. R. Shadley ◽  
E. F. Rybicki ◽  
D. J. Greving ◽  
J. R. Shadley ◽  
...  
Author(s):  
L. Dekhtyar ◽  
A. Kleyman ◽  
S. Berman ◽  
V. Andreychuk

Abstract Future development of thermal spray processes and new composite materials raises an important problem concerning the transition from qualitative to quantitative methods of coatings evaluation. It is well known that thermal spray coating deposition in most cases is accompanied by the formation of temporal and residual stresses through the coating thickness. For proper evaluation of formed stressed state it is extremely important to know the real value of elastic characteristics in different layers of the coating. This problem has become more complicated taking into consideration the variety of materials, different spray parameters, number of coating layers and extreme service conditions. These values can be obtained only from experimentation. Elastic characteristics (EC) could be used in many calculations, such as durability, stiffness, fatigue, vibration and others. This paper describes new methods of experimental determination of elastic characteristics presumed as variable throughout the coating thickness. Influence of coating composition, particle size of initial powders, spray parameters, post-treatment and other factors on elastic modulusses were studied. Obtained experimental data for different materials supplement existing data and can be used for evaluation of residual stresses and other purposes.


2006 ◽  
Vol 20 (25n27) ◽  
pp. 3599-3604 ◽  
Author(s):  
HIROYUKI AKEBONO ◽  
JUN KOMOTORI ◽  
HIDETO SUZUKI

The Thermal spraying is one of the most popular surface coating techniques. To achieve the most efficient use of this technique in practice, it is very important to clarify the fatigue properties of steel coated with a thermal spray coating. In this study, to clarify the effects of coating thickness on the fatigue properties of the steel substrate, three types of sprayed specimens with different coating thickness (0.2, 0.5 and 1.0mm) were prepared and fatigue tests were carried out. Coating thickness strongly affected the fatigue properties; the thinner the coating thickness, the higher the fatigue strength. Fatigue crack propagation behaviors were observed. Accordingly the fatigue cracks propagated through many defects on the coated surface. The sizes and number of the coating defects were determined by coating thickness; the thicker the coating thickness, the larger the defect and number. Therefore, the sprayed specimens with thinner coatings indicated higher fatigue strength. Furthermore, estimations of the fatigue strength were performed by using Murakami's equation. The fatigue strengths of thermal spray coated specimens were estimated by three parameters; (i) maximum size of coating defects estimated by statistics of extreme value, (ii) hardness of the matrix and (iii) volume fraction of coating defects.


Particuology ◽  
2009 ◽  
Vol 7 (5) ◽  
pp. 368-372 ◽  
Author(s):  
Yangbao Qian ◽  
Linzhong Du ◽  
Weigang Zhang

2018 ◽  
Vol 284 ◽  
pp. 1151-1156
Author(s):  
Lenar N. Shafigullin ◽  
A.R. Ibragimov ◽  
A.I. Saifutdinov

C. C. Berndt advanced investigations of mechanical properties of thermal spray coatings under 4-point bending. He found that this investigation method is sensitive to the mechanical properties of thermal spray coatings.This paper contains the detailed investigation results for thermal spray coatings of zirconium dioxide under 4-point bending, i.e. tests of the specimens subjected to spraying at varying conditions and pre-test soaking with the various duration at 1100 °С.It was established how the mechanical properties of thermal spray coatings changed depending on the spraying mode and high temperature soaking. The test results show that the double heat treatment of coatings is more preferable than one-time heat treatment as it make the properties change linearly. It is more easily controllable during operation of the components with thermal spray coating.


BioResources ◽  
2016 ◽  
Vol 12 (1) ◽  
Author(s):  
Mojgan Nejad ◽  
Romina Shafaghi ◽  
Larry Pershin ◽  
Javad Mostaghimi ◽  
Paul Cooper

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