Er2O3 coating for tritium permeation barrier has been fabricated on steel substrates by a filtered arc deposition method at room temperature and 973 K. Thermal expansion of the oxide layer and the substrate induced peel-off of the coating. The non-crystalline layer is thought to play a role in forming a uniform surface coating. Five cycles of permeation measurements at 773-973 K resulted in no degradation of the coating. Different permeation behaviors are seen between degassing for 12 h at 873 K and at room temperature. Low hydrogen background following degassing at 873 K helps detect the transition to deuterium permeation. The permeation flux following different degassing conditions eventually approached comparable levels.