Quanzhong Guo

Internal Oxidation of Binary A-B Alloys by Two Oxidants: Double Internal Oxidation of B in the Presence of an External AX(m) Scale

The kinetics of the simultaneous internal oxidation of the reactive component of binary A–B alloys by two oxidants X–Y (double internal oxidation) in the presence of an external scale of a compound of the noble component A have been investigated theoretically and numerically on the basis of the theory of oxidation of binary alloys by a single oxidant. The effects of the concentration of the reactive element B, of the diffusion coefficients of both oxidants and of the alloying element and of the rate of growth of the external scale on the kinetics of growth of the two internal oxidation zones have also been discussed.

Study of filiform corrosion inhibition by a compact plasma electrolytic oxidation film on a AZ31 Mg alloy

This work reports that the filiform corrosion of a AZ31B Mg alloy can be inhibited by compact plasma electrolytic oxidation (PEO) under a transient self-feedback control mode. Corrosion protection of the C-PEO film was investigated through an immersion test of 3.5 wt% NaCl solution and a simulative service environment test of NSST, respectively. The results revealed that compactness of the film significantly influenced the corrosion protection property of the C-PEO-coated Mg alloy, and the results are summarized as follows: (1) good compactness of the PEO film prevented the soluble ions from diffusing into the scratch; (2) the high insulation of the compact PEO film can slow down cathodic current; (3) the corrosion products could deposit on the scratch and block the active sites on the Mg alloy surface.