Abstract:Fe-Ni-Cr alloy foil was pulse electrodeposited from the trivalent chromium bath. Orthogonal design was used to optimize the processing parameters. The effects of the electrodeposition parameters such as complexing agent and temperature on the composition of alloy foil were investigated systematically. The Fe-Ni-Cr alloy foil was characterized by SEM, EDS and XRD. The optimal process conditions are followed as that: 50 g·L-1 CrCl3·6H2O, with 16 A·dm-2 current density, the period with 100 ms, the duty cycle with 0.3, at 60 ℃ temperature in the solution of pH 1~1.5 with 45 minutes electroplating. The 20-30 μm thick Fe-Ni-Cr alloy foil with a smooth and uniform appearance was obtained, which contains (62~67)wt% Fe, (30~33)wt%Ni and (3~5)wt% Cr. The results indicate the alloy foil is piled up compactly with sphericity and its grain size less than 100 nm; and the main phases are the α-Fe or γ-Fe solid solution with Cr. When Cr content exceeds 4wt%, the main phase would be γ-Fe. The alloy foil also exhibits better electrical, mechanical performance and corrosion resistance with 68.66×10-6 Ω·cm resistivity, 5819 MPa micro-hardness and 1.685×10-6A·cm-2 corrosion current density in 3.5%NaCl solution respectively. Furthermore, the mechanism of co-deposition Fe-Ni-Cr was studied by means of polarization curve and cyclic voltammetry. The results demonstrate that the complexing agent changes the deposited potential of Fe, Ni, Cr, respectively and makes the co-deposition possible