Microstructure of MmM5/Mg multi-layer hydrogen storage films prepared by magnetron sputtering

✍ Scribed by L.Z. Ouyang; H. Wang; M. Zhu; J. Zou; C.Y. Chung

• Book ID: 102889526
• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 722 KB
• Volume: 64
• Category: Article
• ISSN: 1059-910X
• DOI: 10.1002/jemt.20089

✦ Synopsis

Abstract

Multi‐layer hydrogen storage thin films with Mg and MmNi~3.5~(CoAlMn)~1.5~ (here Mm denotes La‐rich mischmetal) as alternative layers were prepared by direct current magnetron sputtering. Transmission electron microscopy investigation shows that the microstructure of the MmNi~3.5~(CoAlMn)~1.5~ and Mg layers are significantly different although their deposition conditions are the same. The MmNi~3.5~(CoAlMn)~1.5~ layer is composed of two regions: one is an amorphous region approximately 4 nm thick at the bottom of the layer and the other is a nanocrystalline region on top of the amorphous region. The Mg layer is also composed of two regions: one is a randomly orientated nanocrystalline region 50 nm thick at the bottom of the layer and the other is a columnar crystallite region on top of the nanocrystalline region. These Mg columnar crystallites have their [001] directions parallel to the growth direction and the average lateral size of these columnar crystallites is about 100 nm. A growth mechanism of the multi‐layer thin films is discussed based on the experiment results. Microsc. Res. Tech. 64:323–329, 2004. © 2004 Wiley‐Liss, Inc.