Thermal spraying. Measurement of the electrical conductivity of thermal sprayed non-iron metal coatings by means of eddy current method

2016 ◽  
2012 ◽  
Vol 548 ◽  
pp. 377-381
Author(s):  
Shakoor Abdul ◽  
Zheng Gan Zhou

Eddy current method can be used for non-destructive assessment of residual stress. In order to relate electrical conductivity change to the residual stresses in the welded joints, piezoresistivity of 5A06 has been investigated using samples heat treated at 2500C and 4000C. These samples represent weld zones with different thermal exposure. A directional eddy current probe with a Hall Effect sensor was used to evaluate stress coefficient of electrical conductivity due to applied uniaxial tensile load on the samples. The electromagnetic forward model was solved using FEM package and linear conductivity inversion was formulated to express probe output in terms of electrical conductivity. The piezoresistivity coefficients of samples, calculated from the derivative of stress-conductivity relation, were compared. The results indicate that coefficients vary inversely with annealing temperature.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3642
Author(s):  
Samira Gruber ◽  
Lukas Stepien ◽  
Elena López ◽  
Frank Brueckner ◽  
Christoph Leyens

So far, copper has been difficult to process via laser powder bed fusion due to low absorption with the frequently used laser systems in the infrared wavelength range. However, green laser systems have emerged recently and offer new opportunities in processing highly reflective materials like pure copper through higher absorptivity. In this study, pure copper powders from two suppliers were tested using the same machine parameter sets to investigate the influence of the powder properties on the material properties such as density, microstructure, and electrical conductivity. Samples of different wall thicknesses were investigated with the eddy-current method to analyze the influence of the sample thickness and surface quality on the measured electrical conductivity. The mechanical properties in three building directions were investigated and the geometrical accuracy of selected geometrical features was analyzed using a benchmark geometry. It could be shown that the generated parts have a relative density of above 99.95% and an electrical conductivity as high as 100% International Annealed Copper Standard (IACS) for both powders could be achieved. Furthermore, the negative influence of a rough surface on the measured eddy-current method was confirmed.


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