DETECTION AND EVALUATION OF DELAMINATION USING ACOUSTIC EMISSION METHOD IN THERMALLY SPRAYED COATING UNDER TENSILE STRESS

2008 ◽  
Vol 22 (11) ◽  
pp. 839-844 ◽  
Author(s):  
YOSHIKO SHINHARA ◽  
KOZO OHTANI ◽  
TAROU TOKUDA ◽  
FUMIHIRO SUZUMURA ◽  
MITSUO KIDO
Keyword(s):  
Cross Section ◽  
Ceramic Coating ◽  
Tensile Load ◽  
Emission Method ◽  
Thermally Sprayed Coatings ◽  
Static Tensile ◽  
Sprayed Coating ◽  
The Relationship ◽  
Thermally Sprayed ◽  
Sprayed Coatings

AE was measured under a static tensile load for the thermally sprayed ceramic coating in order to investigate the relationship between the detected m-value and the destruction (delamination) of the sprayed coating. This was an effective method to detect and evaluate the delamination of a sprayed coating based on the m-value, because changes of the m-value were closely related in thermally sprayed coatings. Stress level of the delamination analyzed by AE method was almost the same as that predicted by the ESPI method. The generation of delamination was confirmed by cross-section observation of the coating using both stress levels. Therefore, the ESPI method seems to be an effective way to define and evaluate the delamination of sprayed coating determine.

Characterization of Structure of Thermally Sprayed Coating

1998 ◽  
Author(s):  
C.J. Li ◽  
Y. He ◽  
A. Ohmori
Keyword(s):  
Lamellar Structure ◽  
Structural Parameters ◽  
Lamellar Thickness ◽  
Pore Networks ◽  
Bonding Ratio ◽  
Sprayed Coating ◽  
The Relationship ◽  
Thermally Sprayed ◽  
Sprayed Coatings

Abstract The structure of a thermally sprayed coating is generally of lamellar structure. There is generally porosity in the coating. The examination shows that the relationship between properties and porosity for conventionally processed porous materials is difficult to be applied to thermally sprayed coating because of complex pore networks. The lamellar structure of the coating and the bonding at the interfaces between lamellae often determine the properties of coating. It is generally difficult to evaluate quantitatively the structure of a thermally sprayed coating because of complicated pore networks in the coating. With the filling of the material different from the composition of the coating into the pores the structure of the coating including nonbonded interface area and also generally referred pores can be visualized. According to the distribution of filler in the coating the structure of a coating can be quantitatively evaluated using structural parameters such as lamellar thickness, lamellar bonding ratio, the width of interface gap and so on. The structural parameters necessary to describe the lamellar structure of thermal sprayed coatings and a method based on the pore filling and analysis of the distribution of filled materials are proposed.

Influence of Reaction Enthalpy on the Microstructure of Laser-Alloyed Coatings

2000 ◽  
Author(s):  
J. Wilden ◽  
H. Frank
Keyword(s):  
Solidification Process ◽  
Laser Remelting ◽  
Microstructure Formation ◽  
Reaction Enthalpy ◽  
Reaction Heat ◽  
Metallurgical Bonding ◽  
Thermally Sprayed Coatings ◽  
Sprayed Coating ◽  
Thermally Sprayed ◽  
Sprayed Coatings

Abstract Some applications of thermally sprayed coatings need a metallurgical bonding of substrate and coating. This can be reached by laser remelting of a thermally sprayed coating, which causes, on the other hand, a certain dilution of the substrate elements into the coating. This article discusses the influence of reaction enthalpies on the microstructure formation in the alloying systems Ni-Al and Ti-Al. Experimental work and simulation were done to examine the time constants of solidification influenced by laser dwell time and reaction enthalpy. It was observed that, for short dwell times, the reaction heat dominates the solidification process and the microstructure formation.

Influence of Pressure in the Nozzle Combustion Chamber on the Porosity and Hardness of WC - Co Coatings Created by HVOF Technology

2015 ◽  
Vol 818 ◽  
pp. 74-77
Author(s):  
Jaromír Moravec ◽  
Václav Kaška
Keyword(s):  
Combustion Chamber ◽  
Metal Powders ◽  
Ferrous Metals ◽  
Functional Surfaces ◽  
Thermally Sprayed Coatings ◽  
The Individual ◽  
Sprayed Coating ◽  
Thermally Sprayed ◽  
Non Destructive ◽  
Sprayed Coatings

Thermally sprayed coatings, together with the deposition, belong among the most important technology both in the section of renovation and creation of functional surfaces. With the help of this technology it is possible to considerably improve the working life of the individual functional parts or to improve the range of their service parameters. Thermally sprayed coatings offer great variability both in light of backup materials (steels, non-ferrous metals, plastics), and in light of functional surfaces (metal powders, carbidic mixtures or ceramics). This paper describes individual types of powders with a view to properties and application possibilities of powders on the basis of W carbides with utilization of HVOF technology including a description of such method. Moreover the paper describes destructive and non-destructive tests for thermally created coatings. The experimental part is focused on the influence of pressure in the HVOF nozzle combustion chamber on the porosity and hardness of thermally sprayed coating for W carbide powders with different percentages of Co.

Thermal Spraying of High Performance Thermoplastics

1998 ◽  
Author(s):  
E. Lugscheider ◽  
C. Herbst ◽  
A. Fischer
Keyword(s):  
High Performance ◽  
Elevated Temperatures ◽  
Thermal Spraying ◽  
Paper Coatings ◽  
Thermally Sprayed Coatings ◽  
Ft Ir ◽  
Ir Analysis ◽  
Thermally Sprayed ◽  
Sprayed Coatings ◽  
Wipe Tests

Abstract Thermally sprayed coatings of high performance thermoplastics are of interest espacially for the chemical industry for anti-corrosion applications at elevated temperatures. In this paper coatings of polyetherether-keton (PEEK) and polyphenylen-sulphide (PPS) have been produced by simple flamespraying. They have been investigated by optical metallography, FT-IR analysis and DSC-analysis. Among the coating properties also the "in-flight" particles have been studied by wipe-tests and FT-IR analysis in order to assess possible decomposition effects during spraying.

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