Morphologies and Influential Factors of Forsterite Film in Grain-Oriented Silicon Steel

Glass Film Formation on GOES Surface during High-Temperature Annealing: The Mechanism with Amorphous Phase Formation

“…The surface layer of GOES has been determined to be in the (α + γ) double-phase region at the DA temperature. According to both calculated and experimental data [ 17 , 18 , 19 , 20 , 21 ], the main phases in the oxide surface layer are FeO, FeSiO 3 , Fe 2 SiO 4 , MnSiO 3 , Mn 2 SiO 4 , SiO 2 and combinations thereof.…”

“…HTA is carried out in bell-type furnaces in order to obtain a coarse-crystalline (110) [001] texture and refine the metal and create a surface glass film that mainly consists of Mg 2 SiO 4 [ 3 , 8 , 20 ]. Metal coils with an MgO coating are annealed at a heating rate of 10–25°/h first up to ~650 °C in an atmosphere of hydronitric mixture, then up to ~1150 °C in a dry hydrogen atmosphere.…”

“…The glass film is formed as a result of the interaction between MgO particles and the steel surface oxidized after DA: the layer formed during HTA is a brittle glass-like film. The studies [ 3 , 7 , 14 , 20 ] showed that the final IC was double-layer system, whereby the forsterite (Mg 2 SiO 4 ) layer had been formed first and then coated with aluminum orthophosphate. The thickness of IC is ~4 µm according to [ 7 ].…”