Micrographs showing magnesium hydroxide around the DyH2 particles in Mg–20 wt% Dy alloy. (a) Secondary electron image by scanning electron microscopy. The specimen was prepared using method (i). (b) Bright-field image by TEM. During grinding and thinning the specimen was in contact with water. EDX results for point 1: 25.6 at.% Mg, 70.1 at.% Dy and 4.3 at.% O; and for point 2: 48.3 at.% Mg, 1.3 at.% Dy and 50.4 at.% O.