Photothermal Radiometry of Thermal Spray Coatings: Thermophysical Properties and Disbonding Effects Characterization

2000 ◽  
Author(s):  
A. Mandelis ◽  
J.A. Garcia ◽  
B. Farahbarhsh
Keyword(s):  
Thermophysical Properties ◽  
Photothermal Radiometry ◽  
Experimental Results ◽  
In Situ Monitoring ◽  
Spray Coatings ◽  
Interfacial Defects ◽  
Steel Substrates ◽  
Sprayed Coatings ◽  
Thermal Sprayed Coatings

Abstract Laser infrared photothermal radiometry (PTR) can be used to determine the thermophysical properties (thermal diffusivity and conductivity) and interfacial defects (i.e. disbonding) of various thermal sprayed coatings on carbon steel substrates. PTR experimental results are compared with a one-dimensional photothermal model that can take into account roughness affects and interfacial defects by considering a roughness equivalent-layer and an equivalent-thermal resistance, respectively. The foregoing thermophysical parameters of the thermal sprayed coatings are obtained when a multi-parameter optimization algorithm is used to fit the PTR experimental results. The potential of the PTR technique for in-situ monitoring of the coating process and the characterization of the thermal sprayed coatings will be discussed in this paper.

Cavitation Resistant Thermal Spray Coatings on Diesel Engine Parts

2000 ◽  
Author(s):  
Y. Borisov ◽  
V. Bogush
Keyword(s):  
Nickel Alloys ◽  
Cavitation Erosion ◽  
Thermal Spraying ◽  
Spray Coatings ◽  
Steel Wires ◽  
Mechanical Mixtures ◽  
Cored Wires ◽  
Sprayed Coatings ◽  
Spraying Method ◽  
Thermal Sprayed Coatings

Abstract This work is devoted to the study of peculiarities of thermal sprayed coatings behavior under conditions of cavitation, as well as the elaboration of compositions of cavitation-resistant coatings and technology for their application with the aim of engine cylinders sleeves protection from cavitation-erosion destruction. The methods of arc metallization, flame and plasma spraying were used for coatings deposition. Powders of metal alloys and oxides, mechanical mixtures of nickel alloys with carbides, wires and flux-cored wires were applied as materials for thermal spraying. Method of magneto-striction vibration was used to determine the coatings cavitation resistance. A correlation between a bond strength of coatings and the character of their cavitation destruction was established. The best results were obtained in the case of using stainless steel wires and flux-cored wires using. Resistance of coated diesel engines sleeves was increased 1.6 times in comparison with sleeves without coatings. Semi-automatic line for arc metallization of diesel sleeves with a production of 600,000 sleeves per year was designed, build up and put into operation.

In-Process Damage Monitoring and Stress Analysis of Thermal Spray Coating

2007 ◽  
Vol 353-358 ◽  
pp. 2403-2406
Author(s):  
Koichi Taniguchi ◽  
Manabu Enoki ◽  
Koichi Tomita
Keyword(s):  
Thermal Spray ◽  
Laser Interferometer ◽  
Spray Coating ◽  
Thermal Spray Coating ◽  
In Situ Monitoring ◽  
Spray Coatings ◽  
Damage Monitoring ◽  
Process Damage ◽  
Ae Signals

AE method is a well-known technique for in-situ monitoring of damage behavior by attached piezoelectric transducer. However, this conventional detection of AE signals has certain limitations. In recent years, numerous efforts have addressed the substitution of laser-based techniques for ultrasonic nondestructive evaluation in place of conventional piezoelectric transducers. Especially, a laser interferometer can be used to measure a displacement or velocity at materials surface using Doppler-shift. However, there are few reports referring to the detection of AE signals in the practical materials and testing because of the difficulty of experiments. We developed the AE measurement system with laser interferometer to apply this technique to microcrack evaluation and reported the quantitative AE analysis in various materials. This paper demonstrates AE results from thermal spray coatings at elevated temperature.

Analysis of semitransparent layered materials by modulated photothermal radiometry: application to the bonding and thickness control of enamel coatings

1986 ◽  
Vol 64 (9) ◽  
pp. 1297-1302 ◽  
Author(s):  
Michel Egee ◽  
Robert Dartois ◽  
Jean Marx ◽  
Christian Bissieux
Keyword(s):  
Theoretical Model ◽  
Thermal Resistance ◽  
Coating Thickness ◽  
Thermophysical Properties ◽  
Layered Materials ◽  
Photothermal Radiometry ◽  
Experimental Results ◽  
Adhesion Properties ◽  
Thickness Control

To use modulated photothermal radiometry to control the thermophysical properties of enamel coatings, we first analytically resolve a theoretical model with two finite semitransparent layers and thermal-resistance interface; then we experimentally study several samples with various adhesion properties. The comparison of the experimental results with the calculations allows one, under the present conditions, to point out the possibilities and limits of the method, mainly for the control of coating thickness and delaminations.

In situ measurement of residual stresses and elastic moduli in thermal sprayed coatings

2003 ◽  
Vol 51 (3) ◽  
pp. 873-885 ◽  
Author(s):  
J. Matejicek ◽  
S. Sampath ◽  
D. Gilmore ◽  
R. Neiser
Keyword(s):  
Residual Stresses ◽  
Elastic Moduli ◽  
In Situ Measurement ◽  
Sprayed Coatings ◽  
Thermal Sprayed Coatings

scholarly journals Towards Reliable Thermal Spray Coatings: An Integrated Approach

2000 ◽  
Author(s):  
Sanjay Sampath
Keyword(s):  
Rapid Heating ◽  
Processing Condition ◽  
Thermal Spraying ◽  
Integrated Approach ◽  
Spray Coatings ◽  
Powder Particles ◽  
Plasma Sprayed ◽  
Individual Droplet ◽  
Sprayed Coatings ◽  
Thermal Sprayed Coatings

Abstract Thermal sprayed coatings are used extensively in engineering components for a variety of protective coating applications. Thermal spraying is a highly dynamic process resulting from rapid heating /accelerating of powder particles in a flame, followed by impact and rapid solidification of the droplets (splats). A splat resulting from the flattening of an individual droplet is the basic building block (unit cell) of the thermal sprayed microstructure. Phase and microstructure of the splats (intrinsic) and the integration of the splats (extrinsic) are both affected by processing condition and the properties of a plasma sprayed deposit are directly related to this complex anisotropic microstructure. These affect both performance and reliability of sprayed surfaces.

Slurry Erosion Behavior of Thermal Spray Coatings

2015 ◽  
pp. 268-293
Author(s):  
Harpreet Singh Grewal ◽  
Harpreet Singh
Keyword(s):  
Surface Modification ◽  
Thermal Spray ◽  
Thermal Spray Coatings ◽  
Slurry Erosion ◽  
Erosion Behavior ◽  
Spray Coatings ◽  
Hydro Power Plants ◽  
Surface Modification Techniques ◽  
Sprayed Coatings ◽  
Thermal Sprayed Coatings

Slurry erosion is a degrading phenomenon usually observed in machineries dealing with particle-laden fluid such as hydro power plants, ship propellers, pump impellers, valves, and connecting pipes. The low erosion resistance of commonly employed structural materials prompts the use of different surface modification techniques. Among several types of surface modification techniques, thermal spraying has achieved a significant recognition worldwide due to its versatile nature. In this chapter, slurry erosion behavior of thermal sprayed coatings has been discussed with special emphasis on the contribution of different coating related parameter. It has been observed that microstructure play an important role in determining the slurry erosion performance of thermal spray coatings. Different microstructural features such as splat boundaries, pores, un-melted particles, and cracks are detrimental for the thermal spray coatings exposed to erosive environment. A parameter useful for identification of primary erosion mechanism for thermal sprayed coatings is also discussed.

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