Growth of thick and long Fe oxide whiskers from Fe plate covered with SiO2 layer

Abstract

The current study aims to fabricate thick and long Fe oxide whiskers using the process of stress-induced migration. Heating a polished Fe plate covered with a SiO2 layer at 750 °C causes Fe oxide whiskers to grow on the surface, whose diameter and length continue to increase along with increasing SiO2 layer thickness up to 53 nm and decrease for thicker layers. An optimal discharge resistance of the SiO2 layer was considered responsible for the formation of thick and long whiskers as it allows for a large accumulation of Fe below the SiO2 layer; discharge is observed at weak spots in cases where the driving force is the highest. Consequently, the Fe oxide whiskers of 0.57 μm diameter and 14.3 μm length were obtained after 2 h of heating.