電析金属クロムの結晶方位と成長状態

抄録

The microstructure, uniformity and growth rate of metallic chromium films that were electroplated both continuously and intermittently in a solution of CrO₃ 50g/l, H₂SO₄ 0.5g/l, up to a thickness of about 100nm on steel and iron, were studied by means of transmission electron microscopy, electron diffraction and X-ray energy spectrometry. During continuous plating for periods shorter than 4 seconds, platelike chromium film grew epitaxially on iron substrate and the crystallographic relation between them was as follows. Fe (001)||Cr(001), Fe[110]||Cr[110] Fe(111)||Cr[110]||Cr[110] In continuous plating for periods longer than 4 seconds, and in intermittent plating, metallic chromium grew in various forms and in various crystallographic orientations. In continuous plating, platelike chromium grew in (111) grains for which the growth rate was constant. In (001) chromium grains, modified pyramidlike chromium formed on the platelike chromium. The mean growth rate up to a thickness of of 15nm was the same as for the (111) chromium grains after which a low growth rate stage was observed followed by a high growth rate stage. In intermittent plating, (001) chromium grains a large amount of granular chromiums grew on the initial deposited platelike chromium, and the mean growth rate increased as much as threefold after the current was interrupted. In (111) chromium grains only a small amount of granular chromiums formed, and the mean growth rate was almost the same as in continuous plating. The uniformity of the (111) chromium grains was better than that of the (001) grains in both continuous and intermittent plating.