Abstract
In General, Mg-alloys show a low load for environment, but a high chemical activity of Mg often prevents the products of Mg-alloys from recycling. It is necessary as a first step to clarify the mechanisms of material degradation with age, in order to realize the reuse. The purpose of this research is to study corrosion mechanism and the rate of Mg-alloy (AZ91D; table. 1) in 0.9% NaCl aq.sol. with the help of optical microscope, μ-X-ray diffraction, scanning electron microscope, and profile meter. The acquired mechanisms are described as follows. (1) the corrosion of Mg (α phase) begins at just steeping. α phase becomes MgCl_2・4H_2O, etc. (2) the corrosion of Al_<12>Mg_<17> (β phase) gradually increases, and β phase becomes Mg-Al-O, etc. How to apply the acquired mechanisms to life cycle assessment will be discussed in the near future.
