ＰＶＤ法により作製したＭｇ薄膜の結晶配向性とモルフォロジーおよびその耐食特性

Abstract

Magnesium thin films were prepared on cold-rolled steel substrates by vacuum evaporation and ion plating. The influence of argon gas pressure and substrate bias voltage on the crystal orientation and molphology of the films was characterized by X-ray diffraction and scanning electron micrography, respectively. The crystal orientation of magnesium thin films deposited at a high gas pressure of 7.3Pa exhibited (002) preferred orientation, regardless of the substrate bias voltage. With an increase in argon gas pressure, film morphology changed from columnar to granular, and surface crystal grain-size and film thickness decreased. The morphology and crystal orientation offilms depended not only on gas pressure but also on bias voltage, an increase in bias voltage having a similar effect to a decrease in gas pressure. The observed phenomena can be explained by the gas adsorption inhibition effect and the ion sputtering effect. The effect of the crystal orientation and morphology of the magnesium thin films on corrosion behavior was estimated by measuring anodic polarization curves in deaerated 3%NaCl solution. Mgnesium thin films that exhibited (002) preferred orientation and granular structure showed good corrosion resistance. It was confirmed that the corrosion resistance of magnesium thin film can be improved by controlling crystal orientation and morphology.