THERMAL INSULATION CERAMIC COATINGS

1959 ◽  
Author(s):  
Alan V. Levy
Keyword(s):  
Thermal Insulation ◽  
Ceramic Coatings ◽  
Insulation Ceramic

scholarly journals Moisture Behavior of Thermal Insulation Coating Consisted of Vacuum-Hollow Nano-Ceramic Microspheres

2018 ◽  
Author(s):  
Dávid Bozsaky
Keyword(s):  
Thermal Insulation ◽  
Material Properties ◽  
Time Trend ◽  
Ceramic Coatings ◽  
Building Industry ◽  
Mathematical Connections ◽  
Thermal Insulating ◽  
Insulation Coating ◽  
Insulation Quality ◽  
Thermodynamic Processes

Nanotechnology-based thermal insulation materials have appeared in building industry in the last two decades. Among them thermal insulating coatings consisted of vacuum-hollow nano-ceramic microspheres are the subjects of most professional discussion. Most studies about these coatings focus only on examination of thermodynamic properties, because there is still no consensus in academic circles about thermodynamic processes inside nano-ceramic coatings. These professional discussions distract attention from other unknown but also important material properties, like behavior by contact with moisture. This paper summarizes the results of moisture behavior tests with nano-ceramic thermal insulation coatings which were conducted to determine the time trend of water absorption, as well as volume, mass and thermal insulation quality changes caused by increasing moisture content. Analyzing the results mathematical connections were found to describe the relation between water content, dimensional and thermal conductivity changes.

scholarly journals Porosity Characterization and Its Effect on Thermal Properties of APS-Sprayed Alumina Coatings

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 601
Author(s):  
Wolfgang Tillmann ◽  
Omar Khalil ◽  
Mohamed Abdulgader
Keyword(s):  
Pore Size ◽  
Thermal Insulation ◽  
Thermal Spraying ◽  
Total Porosity ◽  
Ceramic Coatings ◽  
Atmospheric Plasma ◽  
Powder Size ◽  
Feedstock Powder ◽  
Alumina Coatings ◽  
Plasma Sprayed

In the thermal spraying process, the porosity of ceramic coatings contributes directly to the efficiency of the thermal insulation. The size, shape, and distribution of the pores determine the level of both thermal and sintering resistance. In this work, three different atmospheric plasma sprayed (APS) alumina coatings were fabricated with the same spraying parameters using alumina powders with fine, medium, and coarse particle size. The microstructure of the obtained coatings was analyzed regarding the obtained total porosity, pore size, and pore shape. It was found that it is expedient to divide the pore size range into fine, medium, and large sizes. The shape was characterized with regard to the circularity aspect. In this way, all types of cracks can be considered as oblate pores and were included in the calculation of the total porosity. In the case of using fine feedstock powder, the densest coatings were produced among all coatings, and the fraction of fine pores and cracks are thereby substantially higher. However, the total porosity increases with increasing feedstock powder size. A connection was also made between thermal insulation and porosity fraction which includes fine pores and cracks.

scholarly journals Series of Experiments with Thermal Insulation Coatings Consisted of Vacuum-Hollow Nano-Ceramic Microspheres

2018 ◽  
Vol 11 (1) ◽  
pp. 17-33
Author(s):  
David Bozsaky
Keyword(s):  
Heat Transfer ◽  
Thermal Insulation ◽  
Convective Heat Transfer Coefficient ◽  
Ceramic Coatings ◽  
Complete Agreement ◽  
Transfer Resistance ◽  
Structured Materials ◽  
Thermal Insulating ◽  
Series Of Experiments

Because of the rigorous regulations in the 21st century it has become a serious task for designers to find more effective ways for thermal insulation. One of these options is the application of nanotechnology-based materials. Among nano-scale structured materials the most uncertainties are found about the thermal insulating quality of thermal insulation coatings consisted of vacuum-hollow nano-ceramic microspheres. Complete agreement had not been already found about the mechanism of their insulating effect. In order to explore and describe the thermodynamic process inside nano-ceramic coatings (NCC) 6 series of heat transfer resistance experiments were performed in 2014-2017. Several building structure configurations with 12 different orders of layers were tested with a standard heat flow meter. On basis of these results it could be concluded that in case of nano-structured materials convective heat transfer coefficient might be taken account in different way than in case of traditional macro-structured thermal insulation materials.

Electron microscopy studies of plasma-sprayed materials

1983 ◽  
Vol 41 ◽  
pp. 70-71
Author(s):  
K.R. Subramanian ◽  
A.H. King ◽  
H. Herman
Keyword(s):  
Plasma Spraying ◽  
Substrate Surface ◽  
Flame Temperature ◽  
Ceramic Coatings ◽  
Metallic Substrates ◽  
Hot Plasma ◽  
Almost All ◽  
Plasma Sprayed ◽  
Hostile Environments ◽  
Plasma Spraying Process

Plasma spraying is a technique which is used to apply coatings to metallic substrates for a variety of purposes, including hardfacing, corrosion resistance and thermal barrier applications. Almost all of the applications of this somewhat esoteric fabrication technique involve materials in hostile environments and the integrity of the coatings is of paramount importance: the effects of process variables on such properties as adhesive strength, cohesive strength and hardness of the substrate/coating system, however, are poorly understood.Briefly, the plasma spraying process involves forming a hot plasma jet with a maximum flame temperature of approximately 20,000K and a gas velocity of about 40m/s. Into this jet the coating material is injected, in powder form, so it is heated and projected at the substrate surface. Relatively thick metallic or ceramic coatings may be speedily built up using this technique.

Characterization of thermal barrier coatings formed by electon-beam physical vapor deposition (EB-PVD)

1989 ◽  
Vol 47 ◽  
pp. 426-427
Author(s):  
Ozer Unal
Keyword(s):  
Thermal Barrier Coatings ◽  
Physical Vapor Deposition ◽  
Ceramic Coating ◽  
High Vacuum ◽  
Ceramic Coatings ◽  
High Energy ◽  
Thermal Barrier ◽  
Protective Oxide ◽  
Barrier Coatings ◽  
Energy Beam

Interest in ceramics as thermal barrier coatings for hot components of turbine engines has increased rapidly over the last decade. The primary reason for this is the significant reduction in heat load and increased chemical inertness against corrosive species with the ceramic coating materials. Among other candidates, partially-stabilized zirconia is the focus of attention mainly because ot its low thermal conductivity and high thermal expansion coefficient.The coatings were made by Garrett Turbine Engine Company. Ni-base super-alloy was used as the substrate and later a bond-coating with high Al activity was formed over it. The ceramic coatings, with a thickness of about 50 μm, were formed by EB-PVD in a high-vacuum chamber by heating the target material (ZrO2-20 w/0 Y2O3) above its evaporation temperaturef >3500 °C) with a high-energy beam and condensing the resulting vapor onto a rotating heated substrate. A heat treatment in an oxidizing environment was performed later on to form a protective oxide layer to improve the adhesion between the ceramic coating and substrate. Bulk samples were studied by utilizing a Scintag diffractometer and a JEOL JXA-840 SEM; examinations of cross-sectional thin-films of the interface region were performed in a Philips CM 30 TEM operating at 300 kV and for chemical analysis a KEVEX X-ray spectrometer (EDS) was used.

Calculation of tension in the three-layer pipe with viscoelastic thermal insulation

2019 ◽  
Vol 5 (3) ◽  
pp. 69-78
Author(s):  
V. V. Mozharovsky ◽  
◽  
D. S. Kuzmenkov ◽  
E. A. Golubeva ◽  
◽  
...  
Keyword(s):  
Thermal Insulation
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