Metallic coatings for enhancement of thermal contact conductance

10.2514/3.544 ◽  
1994 ◽  
Vol 8 (2) ◽  
pp. 341-348 ◽  
Author(s):  
M. A. Lambert ◽  
L. S. Fletcher
Keyword(s):  
Thermal Contact ◽  
Thermal Contact Conductance ◽  
Metallic Coatings ◽  
Contact Conductance

Effect of Metallic Coatings on the Thermal Contact Conductance of Turned Surfaces

1990 ◽  
Vol 112 (4) ◽  
pp. 864-871 ◽  
Author(s):  
T. K. Kang ◽  
G. P. Peterson ◽  
L. S. Fletcher
Keyword(s):  
Experimental Data ◽  
Thermal Contact ◽  
Coating Material ◽  
Thermal Contact Conductance ◽  
Enhancement Effect ◽  
Metallic Coatings ◽  
Coating Materials ◽  
Contact Conductance ◽  
Significant Parameter ◽  
Contact Pressures

An experimental investigation was conducted to determine the degree to which the thermal contact conductance at the interface of contacting Aluminum 6061 T6 surfaces could be enhanced through the use of vapor-deposited metallic coatings. Three different coating materials (lead, tin, and indium) were evaluated using four different thicknesses for each coating material. The results verified the existence of an optimum coating thickness, shown to be in the range of 2.0 to 3.0 μm for indium, 1.5 to 2.5 μm for lead, and 0.2 to 0.5 μm for tin. The enhancement factors for thermal contact conductance were found to be on the order of 700, 400, and 50 percent, respectively. Based upon the experimental data, the hardness of the coating materials appears to be the most significant parameter in ranking the substrate and coating material combinations; however, additional experimental data are needed to substantiate this hypothesis. Finally, it was apparent that the thermal contact conductance enhancement effect was greatest at low contact pressures and decreased significantly with increases in the contact pressure.

Thermal Contact Resistance Modeling of Non-Flat, Roughened Surfaces With Non-Metallic Coatings

2000 ◽  
Vol 123 (1) ◽  
pp. 11-23 ◽  
Author(s):  
E. E. Marotta ◽  
L. S. Fletcher ◽  
Thomas A. Dietz
Keyword(s):  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Thermal Contact Conductance ◽  
Metallic Coatings ◽  
Thermomechanical Model ◽  
Contact Conductance ◽  
Flat Surfaces ◽  
Resistance Modeling ◽  
Aluminum Substrates

Essentially all models for prediction of thermal contact conductance or thermal contact resistance have assumed optically flat surfaces for simplification. A few thermal constriction models have been developed which incorporate uncoated, optically non-flat surfaces based on the bulk mechanical properties of the material. Investigations have also been conducted which incorporate the thermophysical properties of metallic coatings and their effective surface microhardness to predict the overall thermal contact conductance. However, these studies and subsequent models have also assumed optically flat surfaces; thus, the application of these models to optically non-flat, coated surface conditions is not feasible without modifications. The present investigation develops a thermomechanical model that combines both microscopic and macroscopic thermal resistances for non-flat, roughened, surfaces with non-metallic coatings. The thermomechanical model developed as a result of this study predicts the thermal contact resistance of several non-metallic coatings deposited on metallic aluminum substrates quite well.

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