Study on Diffusion Coefficient and Activation Energy of Boriding by Molten Salt Pulse Electrodeposition

Boronized layer on the surface of silicon steel was produced by pulse electrodeposition in NaCl ∶ KCl ∶ NaF ∶Na2B4O7=2 ∶ 2 ∶ 1 ∶ 0.04(mole ratio). The diffusion parameters including diffusion activation energy and diffusion constant were obtained by measuring the thickness of boronized layer of sillicon steel in different depositon temperatures and deposition times. The diffusion coefficient of boron in silicon steel under a certain temperature during molten salt pulse electrodeposition can be calculated according to the diffusion activation energy, the diffusion constant and formula. And the accuracy of the diffusion coefficient was verified. Comparing with conventional boriding, the diffusion activation energy of boron during pulse electrodeposition is the same order of magnitude, but the diffusion constant of boron during pulse electrodeposition becomes larger, so the diffusion coeffcient of boron increases efficiently during pulse electrodeposition.