Abstract: Interfacial geometric morphology, chemistry and microstructure have been studied by SEM,EDAX, HREM, and XPS. It is found that the oxide scale/metal interface consists of two layers.The first one is amorphous SiO2 growing inward metal matrix, and the second one under the firstlayer is TiO2 distributing in metal matrix. There is microstructural transition zone at Cr2O3/SiO2intedece, and an atomic mixed zone with 8 nm width at Si02/metal interface. The transitionzone which is saturated with Cr diffusing from oxide scale exists at the oxide scale/glass intedece.The reasons why sand-blasting process can improve bonding strength of the oxide scale and themetal are also discussed. The ideal interfaces are proposed finally.