硝酸イオンを含む非懸濁めっき浴からの Ni -Al (OH) 3 複合薄膜の電析 麻野 亨 a ,林 秀考 a,* ,寺西 貴志 a ,岸本 昭 a ,石井 一也 b a 岡山大学 大学院自然科学研究科 (〒 700-8530 岡山県岡山市北区津島中 3-1-1) b 新日鐵住金㈱ 鉄鋼研究所 (〒 660-0891 兵庫県尼崎市扶桑町 1-8) This study investigated electrodeposition of Ni-Al (OH) 3 composite films from a Watts type bath containing Al 3+ and NO 3 -. Because of NO 3 reduction during nickel electrodeposition, the solution pH near the cathode increases. Then hydrolysis of Al 3+ proceeds. Scanning electron microscopy (SEM) was used to characterize

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... he composite surface. The aluminum hydroxide produced by the hydrolysis of Al 3+ was estimated using energy dispersive X-ray spectrometry (EDX) . Surface roughness of the deposits was measured using a three-dimensional surface profiler. Also, results obtained using X-ray diffractometry (XRD) and electron backscatter diffractometry (EBSD) revealed that the preferred crystallographic orientation of nickel changed from the [100] direction to [110] because of the aluminum hydroxide particles. By increasing the Al 3+ concentration to 5.0×10 3 mol dm 3 , the deposit surface became smooth and the crystal size was found to decrease. Moreover the Vickers hardness increased in comparison to that obtained from an Al 3+ free bath. These phenomena are regarded as strengthening effects related to grain size reduction.