Characterization of Structure of Thermally Sprayed Coating

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.

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

Modern Physics Letters B ◽

10.1142/s0217984908015474 ◽

2008 ◽

Vol 22 (11) ◽

pp. 839-844 ◽

Cited By ~ 1

Author(s):

YOSHIKO SHINHARA ◽

KOZO OHTANI ◽

TAROU TOKUDA ◽

FUMIHIRO SUZUMURA ◽

MITSUO KIDO

Keyword(s):

Cross Section ◽

Ceramic Coating ◽

Tensile Load ◽

Emission Method ◽

Static Tensile ◽

Sprayed Coating ◽

The Relationship ◽

Thermally Sprayed ◽

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.

Correction to: Ultrasonic Characterization of Thermally Sprayed Coatings

Journal of Thermal Spray Technology ◽

10.1007/s11666-019-00842-8 ◽

2019 ◽

Vol 28 (3) ◽

pp. 591-591

Author(s):

Safia Lemlikchi ◽

Jesper Martinsson ◽

Ahmed Hamrit ◽

Hakim Djelouah ◽

Mohammed Asmani ◽

...

Keyword(s):

Ultrasonic Characterization ◽

Thermally Sprayed ◽

Characterization of thermally sprayed coatings for high temperature wear protection applications

Thin Solid Films ◽

10.1016/0040-6090(80)90329-6 ◽

1980 ◽

Vol 73 (1) ◽

pp. 59-77 ◽

Cited By ~ 14

Author(s):

C.C. Li

Keyword(s):

High Temperature ◽

High Temperature Wear ◽

Wear Protection ◽

Thermally Sprayed ◽

Monte Carlo simulation of the lamellar structure of thermally sprayed coatings

Surface and Coatings Technology ◽

10.1016/0257-8972(87)90112-5 ◽

1987 ◽

Vol 32 (1-4) ◽

pp. 261-271 ◽

Cited By ~ 31

Author(s):

O. Knotek ◽

R. Elsing

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Lamellar Structure ◽

Thermally Sprayed ◽

Computational Parametric Analysis of the Mechanical Response of Structurally Varying Pacinian Corpuscles

Journal of Biomechanical Engineering ◽

10.1115/1.4036603 ◽

2017 ◽

Vol 139 (7) ◽

Cited By ~ 1

Author(s):

Julia C. Quindlen ◽

Burak Güçlü ◽

Eric A. Schepis ◽

Victor H. Barocas

Keyword(s):

Mechanical Response ◽

Structural Parameters ◽

Peak Frequency ◽

Lamellar Thickness ◽

Fluid Viscosity ◽

Band Pass Filter ◽

Peak Strain ◽

Pass Filter ◽

The Impact ◽

The Relationship

The Pacinian corpuscle (PC) is a cutaneous mechanoreceptor that senses low-amplitude, high-frequency vibrations. The PC contains a nerve fiber surrounded by alternating layers of solid lamellae and interlamellar fluid, and this structure is hypothesized to contribute to the PC's role as a band-pass filter for vibrations. In this study, we sought to evaluate the relationship between the PC's material and geometric parameters and its response to vibration. We used a spherical finite element mechanical model based on shell theory and lubrication theory to model the PC's outer core. Specifically, we analyzed the effect of the following structural properties on the PC's frequency sensitivity: lamellar modulus (E), lamellar thickness (h), fluid viscosity (μ), PC outer radius (Ro), and number of lamellae (N). The frequency of peak strain amplification (henceforth “peak frequency”) and frequency range over which strain amplification occurred (henceforth “bandwidth”) increased with lamellar modulus or lamellar thickness and decreased with an increase in fluid viscosity or radius. All five structural parameters were combined into expressions for the relationship between the parameters and peak frequency, ωpeak=1.605×10−6N3.475(Eh/μRo), or bandwidth, B=1.747×10−6N3.951(Eh/μRo). Although further work is needed to understand how mechanical variability contributes to functional variability in PCs and how factors such as PC eccentricity also affect PC behavior, this study provides two simple expressions that can be used to predict the impact of structural or material changes with aging or disease on the frequency response of the PC.

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

Thermal Spray 2000: Proceedings from the International Thermal Spray Conference ◽

10.31399/asm.cp.itsc2000p0443 ◽

2000 ◽

Author(s):

J. Wilden ◽

H. Frank

Keyword(s):

Solidification Process ◽

Laser Remelting ◽

Microstructure Formation ◽

Reaction Enthalpy ◽

Reaction Heat ◽

Metallurgical Bonding ◽

Sprayed Coating ◽

Thermally Sprayed ◽

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.

Local Approach to Thermally-Sprayed Coating/Substrate Adhesion through LASAT (Laser Shock Adhesion Test)

Materials Science Forum ◽

10.4028/www.scientific.net/msf.539-543.1067 ◽

2007 ◽

Vol 539-543 ◽

pp. 1067-1073

Author(s):

Sophie Barradas ◽

Michel Jeandin ◽

Régine Molins ◽

F. Borit ◽

L. Berthe ◽

...

Keyword(s):

Cold Spray ◽

Spray Coating ◽

Local Approach ◽

Small Areas ◽

Substrate Adhesion ◽

Cold Spray Coating ◽

Sprayed Coating ◽

Thermally Sprayed ◽

Sprayed Coatings ◽

Rapid Deformation

Three interface factors may influence thermally-sprayed coatings adhesion: interface morphology (as usual), thermal and chemical features. It was shown that these three aspects of adhesion mechanisms are shown to be dependent and very local. It is especially true for cold spray which is one of the most promising spray processes. As this spraying technique is based on rapid deformation, cold spray coating/substrate interfaces show local morphological, thermal and chemical features, in a way that none of them can be neglected. LASAT is particularly suitable for testing these coatings because it can be applied to small areas (~1 mm²). From this, it has the outstanding advantage to be sensitive to fine-scaled phenomena responsible for coating adhesion.

Characterization of Erosion Resistant Cr3C2-NiCr Plasma Sprayed Coatings

Thermal Spray 1996: Proceedings from the National Thermal Spray Conference ◽

10.31399/asm.cp.itsc1996p0123 ◽

1996 ◽

Author(s):

D.-Y. Kim ◽

M.-S. Han ◽

J.-G. Youn

Keyword(s):

Heat Treatment ◽

Erosion Resistance ◽

Process Variables ◽

Graphite Phase ◽

Plasma Sprayed Coatings ◽

Sprayed Coating ◽

Plasma Sprayed ◽

Abstract Properties of an erosion resistant Cr3C2 - NiCr coating have been studied as a function of both plasma spraying process variables and heat treatment. The as-sprayed Cr3C2 - NiCr coating revealed low hardness value of 380-470 Hv, which provided the coating with a poor erosion resistance. This is directly attributed to the decomposition of Cr3C2 constituent into Cr7C3 and graphite phases during the spraying. It was not the effective way to control the process variables such as arc current and stand-off distance for preventing the decomposition of Cr3C2 constituent. A proper heat treatment on the as-sprayed coating increases the hardness of the coating in a great extent up to 900Hv so that the erosion resistance of the coating is clearly improved. This was confirmed to be attributed to the recovery of Cr3C2 at the expense of graphite phase and the formation of Cr2O3 by the heat treatment. In addition, the formation of Cr2O3 phase plays an important role of increasing the erosion resistance of the coating by healing the microcracks of the as-sprayed coating. These are the microstructural features responsible for the high erosion resistance of the coating after a proper heat treatment.