For this preliminary work, Cu metal coatings were produced by electroplating under supercritical argon (sc-Ar) on copper sulphate bath with no additives. Coatings were also produced by supercritical carbon dioxide (sc-CO2) and traditional electroplating for comparison. Mechanical and electrical properties were analysed for all coatings. It was found that sc-CO2 electroplating had the highest grade of grain refinement; however, this meant relatively higher degree of internal stresses, while the sc-Ar electroplating displayed more moderate grain refinement, hence relatively lower internal stress. Advantages of the proposed the sc-Ar method are faster fabrication time compared to the traditional method and desirably lower internal stresses compared to the sc-CO2 method.
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