Accession Number : ADA189385

Title :   A Fundamental Understanding of the Effect of Alloying Elements on the Corrosion Resistance of Rapidly Solidified Mg Alloys.

Descriptive Note : Annual rept. no. 2, 1 Nov 86-31 Oct 87,

Corporate Author : JOHNS HOPKINS UNIV BALTIMORE MD

Personal Author(s) : Kruger, J ; Long, G G ; Tanaka, D K ; Joshi, A ; Makar, G L

PDF Url : ADA189385

Report Date : 16 Nov 1987

Pagination or Media Count : 74

Abstract : During the second year of this project progress was made in the following areas concerned with the effect of alloying elements on the corrosion resistance of RSP Mg alloys: (1) The development of the surface reflection x ray spectroscopic technique (ref1EXAFS) to carry out structural studies on the films on Mg alloys that control corrosion was completed and applied in measurements at the oxygen K-edge of surface films on high purity Mg and AZ61 Mg alloys. The existence of magnesium hydroxide on these surfaces was found. (2) Electrochemical studies of the effect of A1, An, Ce, Nd, Y, Mn, Li, and Ca in melt-spun Mg alloy ribbons on corrosion behavior were carried out. The corrosion rate decreased with increased percentage of A1 and small additions of Zn. It was found that rapid solidification improves the resistance of the alloy studied (AZ61) to localized C1- attack. (3) Surface analytical studies found that only Li and Ca in the RSP Mg alloys have a tendency to be enriched in the films on these alloys. Hydroxides and carbonates were also found in the surface films along with oxides. Keywords: Magnesium alloys, Rapidly solidified alloys, Corrosion, EXAFS, Electrochemistry, Localized corrosion, Passivity.

Descriptors :   *CORROSION RESISTANCE, *MAGNESIUM ALLOYS, *CORROSION RESISTANT ALLOYS, CARBONATES, ELECTROCHEMISTRY, HYDROXIDES, MAGNESIUM COMPOUNDS, OXIDES, RATES, SOLIDIFICATION, STRUCTURAL PROPERTIES, SYNTHESIS(CHEMISTRY), FABRICATION, ALUMINUM, ZINC, LITHIUM, CERIUM, CALCIUM, SURFACE PROPERTIES

Subject Categories : Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE