Determination of the protective properties of electrodeposited organic epoxy coatings on aluminium and modified aluminium surfaces

2005 ◽  
Vol 47 (3) ◽  
pp. 823-834 ◽  
Author(s):  
Z.Ž. Lazarević ◽  
V.B. Mišković-Stanković ◽  
Z. Kačarević-Popović ◽  
D.M. Dražić
Keyword(s):  
Epoxy Coatings ◽  
Protective Properties

scholarly journals Electrochemical properties and thermal stability of epoxy coatings electrodeposited on aluminium and modified aluminium surfaces

2001 ◽  
Vol 66 (11-12) ◽  
pp. 871-880 ◽  
Author(s):  
Vesna Miskovic-Stankovic ◽  
Zorica Lazarevic ◽  
Zorica Kacarevic-Popovic
Keyword(s):  
Thermal Stability ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Charge Transfer Resistance ◽  
Epoxy Coatings ◽  
Transfer Resistance ◽  
Protective Properties ◽  
Chemically Modified ◽  
Thermal Stability Of

The corrosion behaviour of epoxy coatings electrodeposited on aluminium, as well as on electrochemically and chemically modified aluminium were investigated during exposure to 3 % NaCl. Electrochemical impedance spectroscopy (EIS) and thermogravimetric analysis (TGA) were used for the determination of the protective properties of epoxy coatings on aluminium, anodized aluminium, phosphatized and chromatized-phosphatized aluminium. The protective properties of epoxy coatings on anodized and chromatized-phosphatized aluminium are significantly improved with respect to the same epoxy coatings on aluminium and phosphatized aluminium: higher values of the pore resitance and charge-transfer resistance, lower values of the coating capacitance, double-layer capacitance and relative permittivity (from EIS) smaller amount of absorbed water inside the coating (From TGA). On the other hand, the lower values of the ipdt temperature indicate a lower thermal stability of the epoxy coatings on anodized and chromatized-phosphatized aluminium.

scholarly journals Determination of distribution of heat-conducting material concentration in protective layer of thermal protection system panel

2019 ◽  
Vol 23 (Suppl. 4) ◽  
pp. 1025-1034
Author(s):  
Lukasz Brodzik ◽  
Andrzej Frackowiak
Keyword(s):  
Thermal Protection ◽  
Protective Layer ◽  
Heat Conducting ◽  
Conducting Material ◽  
Protective Properties ◽  
Conductive Material ◽  
Time Extension ◽  
Heating Up ◽  
Dope Concentration

Paper presents the problem of heating the damaged insulation of an orbiter. Changes of the insulation?s thermal properties, made by adding conductive material of high value of specific heat in a form of a dope to the protective layer, were examined. An iterative algorithm determining a variable of dope concentration in the material was developed. Insulating material LI900 was used for calculations. Determination of distribution of conductive material concentration was made for materials which, after verification, demonstrated the most beneficial effect on protective properties of the modified insulation layer. Change of properties was to enable time extension of the LI900 insulation tile heating up to the maximal temperature and, additionally, to lowering this temperature.

scholarly journals Protective properties of epoxy coatings electrodeposited on steel electrochemically modified by Zn-Fe alloys

2004 ◽  
Vol 58 (10) ◽  
pp. 450-456
Author(s):  
Jelena Bajat ◽  
Vesna Miskovic-Stankovic ◽  
Zorica Kacarevic-Popovic
Keyword(s):  
Prolonged Exposure ◽  
Passive Layer ◽  
Epoxy Coating ◽  
Constant Voltage ◽  
Epoxy Coatings ◽  
Corrosion Stability ◽  
Protective Properties ◽  
Water Oxygen ◽  
Current Densities ◽  
Fe Alloys

Epoxy coatings were electrodeposited on steel and steel modified by Zn-Fe alloys using the constant voltage method. Zn-Fe alloys were electrodeposited on steel at different current densities. The effect of the Zn-Fe alloy on the corrosion behavior of the epoxy coating was interpreted in terms of the electrochemical and transport properties. It was shown that the best properties, i.e. the largest values of the pore resistance and the smallest values of the coating capacitance, a longer period of almost constant Rp and Cp values, and the smallest diffusion coefficient of water through the epoxy coating, as well as the smallest amount of water absorbed inside the epoxy coating, were found for epoxy coatings on steel modified by a Zn-Fe alloy deposited at 4 A dm-2. During prolonged exposure to 3% NaCl, this Zn-Fe alloy significantly improves the corrosion stability of the epoxy coating: almost unchanged values of Rp and Rct were observed, due to the formation of a pseudo-passive layer of corrosion products, which is a good barrier to the transport of water, oxygen and electrolyte ions.

Optimization of the heat flow by solving inverse problem in the protective layer of the TPS panel

2019 ◽  
Vol 30 (6) ◽  
pp. 2989-3003 ◽  
Author(s):  
Łukasz Brodzik ◽  
Andrzej Frąckowiak
Keyword(s):  
Protective Layer ◽  
Inverse Heat Conduction ◽  
Insulation Layer ◽  
Protective Properties ◽  
Content Type ◽  
Conductive Material ◽  
Time Extension ◽  
Inverse Heat Conduction Problems ◽  
Heating Up

Purpose This paper aims to present the problem of heating the damaged insulation of an orbiter. Design/methodology/approach Changes of the insulation’s thermal properties, made by adding conductive material of high value of specific heat in a form of a dope to the protective layer, were examined. An iterative algorithm determining a variable of dope concentration in the material was developed. Findings Determination of distribution of conductive material concentration was made for materials which, after verification, demonstrated the most beneficial effect on protective properties of the modified insulation layer. The problem of determining the distribution of metal filings concentration in the insulation layer of the coating belongs to inverse heat conduction problems. Originality/value Change of properties was to enable time extension of the LI900 insulation tile heating up to the maximal temperature and, additionally, to lowering this temperature.

Determination of the Influence of Carbonation of Concrete and Corrosion of Steel on Reinforced Concrete Condition

2015 ◽  
Vol 1124 ◽  
pp. 225-230 ◽  
Author(s):  
Kristýna Timcakova ◽  
Daniela Štefková ◽  
Zdeněk Chobola
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Poor Quality ◽  
Protective Properties ◽  
Impact Echo ◽  
Concrete Condition ◽  
Almost All ◽  
Corrosion Of Steel ◽  
Impact Echo Method

Almost all reinforced concrete structures which are exposed to weather effects are threatened by corrosion. The corrosion of steel elements in structures has an influence on lifetime these constructions and adversely affects their properties. However, the steel in concrete structures is protected against corrosion due to the properties of concrete such as high pH or impermeability, but if the concrete is of poor quality and his protective properties are insufficient the corrosion can occur. A problem causes the action of carbon dioxide which has the effect of lowering the pH below the critical value and thereby accelerating the corrosion.Non-destructive methods such as Impact-echo method offer the possibility of easy and quickly detection of initial damage of structure and thus can prevent the occurrence of permanent damage to the whole construction.This article describes the development of corrosion which is caused by carbonation of the concrete and supported by action of chlorides by using Impact-echo method. The paper presents results obtained on the reinforced concrete samples with one steel rod passing through the center. After carbonation concrete the samples were exposed accelerated controlled degradation in aqueous NaCl solution for 4 months.

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