scholarly journals Determination of Nonconductive Coating Thickness Using Electrical Contact Conductance and Surface Profile

Coatings ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 310 ◽  
Author(s):  
Kyungmok Kim ◽  
Jaewook Lee
Keyword(s):  
Coating Thickness ◽  
Electrical Contact ◽  
Surface Profile ◽  
Steel Specimen ◽  
Vertical Displacement ◽  
Relative Displacement ◽  
Optical Microscope ◽  
Electrical Contact Resistance ◽  
Contact Conductance

This paper describes a method to determine the thickness of a nonconductive coating by identifying the transition of material by a change in electrical properties. A slide-hold-slide test was conducted with a worn specimen including an electrodeposited coating layer. Relative displacement was imposed between a metallic stylus tip and a worn steel specimen. After an initial sliding, the tip was held for a certain time to measure electrical contact resistance. During the test, the vertical displacement of the stylus tip was also recorded to draw a surface profile of the worn specimen. Coating thickness on the specimen was determined with a surface profile at the transition of electrical contact conductance. Optical cross-section measurement of the specimen was applied to identify actual coating thickness. Measured results reveal that calculated coating thicknesses are in good agreement with measured values by an optical microscope. The proposed method allows determination of both nonconductive coating thickness and surface profile in a single measurement.

Three-Dimensional Electron-Beam Deflection and Missed Joint in Welding Dissimilar Metals

1997 ◽  
Vol 119 (4) ◽  
pp. 832-839 ◽  
Author(s):  
P. S. Wei ◽  
F. K. Chung
Keyword(s):  
Electron Beam ◽  
Electrical Contact ◽  
Three Dimensional ◽  
Electron Gun ◽  
Beam Deflection ◽  
Beam Power ◽  
Dissimilar Metals ◽  
Electrical Contact Resistance ◽  
Paraboloid Of Revolution

Three-dimensional deflection of the electron beam resulting in a missed joint due to thermoelectric magnetism generated while welding dissimilar metals is systematically investigated. The incident energy rate distribution is assumed to be Gaussian and the deep and narrow welding cavity induced is idealized as a paraboloid of revolution. With a three-dimensional analytical solution for the temperature and by solving Maxwell’s electromagnetic equations, thermoelectric currents, magnetic flux densities, and deflections of the beam are found. The predictions agree with available experimental data. The results find that missed joints can be reduced by increasing the dimensionless accelerating voltage-to-Seebeck e.m.f. parameter, Peclet number, and effective electrical contact resistance parameter, and decreasing dimensionless beam power, magnetic permeabilities, and electrical conductivity ratio between metals 1 and 2. Tilting workpieces and shifting the electron gun from the joint line are also feasible. A three-dimensional analysis is required for a successful determination of beam deflection.

scholarly journals Multiphysical characterization of FSW of aluminum electrical busbars with copper ends

2019 ◽  
Vol 64 (1) ◽  
pp. 59-71 ◽  
Author(s):  
Dagur Ólafsson ◽  
Pedro Vilaça ◽  
Jussi Vesanko
Keyword(s):  
Contact Resistance ◽  
Thermal Loading ◽  
Electrical Contact ◽  
Base Material ◽  
Compressive Force ◽  
Optical Microscope ◽  
Electrical Contact Resistance ◽  
Friction Stir ◽  
Force Relaxation ◽  
The One

Abstract This work investigates the benefits of having an aluminum (Al) busbar with welded copper (Cu) ends, and evaluates the force relaxation phenomena of a pre-loaded bolt joint on Cu versus Al, under cyclic thermal loading. The results show a force relaxation rate 50% lower in the Cu-bolted joint compared with the one in Al. The core of this research is the weldability analysis of Al-Cu butt joints made by friction stir welding (FSW). The materials are AA1050 H14/24 and Cu OF 04 with thickness of 6 mm. Temperature monitoring during the FSW cycle emphasize how heat generation depends mostly on local internal viscoplastic deformation. Tensile, bending, and microhardness tests were used to establish the mechanical properties. Optical microscope and scanning electron microscopy were used to characterize the microstructure. Joining mechanisms in the weld were investigated using energy-dispersive X-ray spectroscopy. The FSW resulted in 85% tensile strength efficiency compared to the Al base material, and 97% electrical conductivity efficiency compared to an ideal bimetallic component made of the same materials with no contact resistance. Electrical resistance of the FSW is 200 times lower than the electrical contact resistance between the Al-Cu materials while under high compressive force.

Determination of Contact Condition at Elevated Temperature

2009 ◽  
Author(s):  
L. St-Georges ◽  
L. I. Kiss ◽  
E. de Varennes
Keyword(s):  
Complex Structure ◽  
Electrical Contact ◽  
Experimental Tests ◽  
Relative Displacement ◽  
Contact Condition ◽  
Friction Mechanism ◽  
Model Complex ◽  
Special Apparatus ◽  
Contact Pressures

To model complex structure with numerous components and solids, the condition of contact between two solids must be adequately described. In this investigation, a special apparatus developed to analyze the condition of contact between two solids is presented. With this apparatus, experimental tests can be performed to determine the condition of friction (static and dynamic and the transition from one to the other) and the thermal and electrical contact resistances between two disk shaped rotating samples of different nature at various temperatures (from ambient up to 1000°C) and contact pressures. To determine the evolution of the friction mechanism as a function of the relative displacement between the solids, an inverse mathematical method has been developed and is presented. The results obtained with the apparatus proposed will provide a better understanding of the contact condition and could be easily incorporated in future mathematical models describing the behaviour of complex, multi layered structures.

New Apparatus for Characterizing Electrical Contact Resistance and Thermal Contact Conductance

2011 ◽  
pp. 1003-1008
Author(s):  
Nedeltcho Kandev ◽  
Hugues Fortin ◽  
Sylvain Chénard ◽  
Guillaume Gauvin ◽  
Marie-Hélène Martin ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Thermal Contact ◽  
Electrical Contact ◽  
Thermal Contact Conductance ◽  
Electrical Contact Resistance ◽  
Contact Conductance ◽  
New Apparatus

New Apparatus for Characterizing Electrical Contact Resistance and Thermal Contact Conductance

2011 ◽  
pp. 1003-1008 ◽  
Author(s):  
Nedeltcho Kandev ◽  
Hugues Fortin ◽  
Sylvain Chénard ◽  
Guillaume Gauvin ◽  
Marie-Hélène Martin ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Thermal Contact ◽  
Electrical Contact ◽  
Thermal Contact Conductance ◽  
Electrical Contact Resistance ◽  
Contact Conductance ◽  
New Apparatus
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