Crystallographic texture evolution during processing of hot dipped and diffusion annealed high silicon electrical steel
The texture of high Si and Al electrical steel produced by hot dipping and diffusion annealing can be significantly modified by the thermomechanical processing. The diffusion of Si and Al from the coating affects the final texture depending on the Si content of the substrate. In low Si substrates a phase transformation gamma-alpha is possible and two different textures are observed. Crystallographic texture is an important characteristic of electrical steel. For the production route described here, a modification of the thermomechanical processing has an important influence on texture development. Further investigation shows how far can be gone in order to reduce the magnetic losses through an advanced texture control.
Chemical and Physical Interactions of Si-Rich Steel Substrates during Hot Dipping Experiments in a Molten Al-(25 wt%)Si Alloy
The chemical and physical interaction between Fe-Si alloys in the range 0-3.8 Si wt% and a molten Al-(Si 25wt%) alloy at 800 °C has been studied for different reaction times (from 0.1 to 200s) by hot dipping tests. Several intermetallic phases have been identified, Fe2Al5, τ1-Al3Fe3Si2, τ2-Al12Fe6Si5, τ3- Al2FeSi and τ4- Al3FeSi2, which already were reported in the literature dealing with the interaction between iron and molten Al-Si alloys. In addition an ordered phase Fe3Si (D03) appears in contact with the Fe-Si substrate. Diffusion reaction and solidification phenomena appear to be involved in the developing of the coating. The growth kinetic has been studied and diffusion appears as the step controlling the intermetallic compounds growth. Special attention was paid to the effect of the microstructure of the dipped sheet on the interaction with the molten alloy. The higher deformed structures react faster; this effect can be explained by the faster diffusion through high diffusivity paths like grain boundaries and dislocations.
A study of the solid state reaction between silicon carbide and iron
Abstract The solid state reaction between SiC and Fe annealed in an Ar–20 vol.% H 2 atmosphere in the temperature range from 1073 to 1373 K for times from 0.5 to 40 h had been studied. The reaction products of Fe 3 Si, Fe(Si), and the graphitic carbon precipitates were generated. The reaction zone is composed of the band structure, i.e. the modulated carbon precipitation zone (M-CPZ)/the random carbon precipitation zone (R-CPZ)/the carbon precipitation free zone (C-PFZ) from the SiC terminal to the Fe terminal, when annealed at 1173 K and above. The formation of the M-CPZ is due to the discontinuous decomposition of SiC. The microhardness values across the reaction zone are the function of the carbon content/microstructure in the M-CPZ and the R-CPZ, and the function of the silicon concentration in the C-PFZ. The reaction follows the parabolic growth law indicating the diffusion-controlled reaction kinetics. The reaction rate constant, K=4.9×10 −4 exp (−(180×10 3 )/RT)  m 2  s −1 is calculated which is in the same order of magnitude as D Fe 3 Si Fe in the temperature range used. The apparent activation energy, 180 kJ mol −1 , is believed to be that of the diffusion of Fe in Fe 3 Si. It indicates that Fe diffusion in Fe 3 Si is the dominating diffusion species of the reaction.