Fabrication of Cu-Al2O3 composite tubes through electroforming process and investigation on the effect of alumina particles on corrosion resistance of the tubes

In this research, Cu-Al2O3 composite tubes were fabricated by electroforming method using a rotating stainless steel rod as cathode and Cu-P alloy as anode. The microstructure, surface morphology, and the effect of alumina second phases on corrosion resistance of the fabricated tubes were investigated by the means of SEM images, X-ray diffraction, and corrosion tests, respectively. X-ray diffraction pattern proved the existence of alumina particles in the copper matrix of the fabricated tubes and also proved that no chemical reaction occurred between these two phases. SEM images indicated that the amount of alumina particles in the copper matrix is a function of its concentration in the electroforming bath, so that it would be maximum when 15 g alumina per liter was used, in the condition of the present study. The results of potentiodynamic polarization test carried out in 3.5 wt. % NaCl solution illustrated that corrosion potential and corrosion current density changed to positive and negative values, respectively, and corrosion rate decrease at all by increasing the amount of alumina particles in copper matrix of the tubes. Electrochemical impedance analysis also proved that corrosion resistance increase due to the presence of alumina in copper matrix.