Aluminization of high purity iron by powder liquid coating Original Research Article

A new powder liquid coating method is proposed for the aluminization of Fe. Mixed powder slurries of Al + Ti or Al + Al2O3 are pasted onto Fe specimens, and the specimens are then dried and heated in a vacuum. Unlike hot dipping or powder pack cementation, this technique can be used to aluminize specimens selectively without the need for special equipment or halides. The amount of Al adhering to the substrate is determined by the Al–Ti reaction or coalescence of molten Al in Al2O3 powder during heat treatment. The Al concentration profile of the modified layer can be controlled by adjusting the powder mixing ratio or heat treatment conditions. The properties of the modified layer are analyzed using a new formulation, where the diffusion equation is treated numerically with consideration of the concentration dependence of the interdiffusion coefficient. The calculated profiles are stable and in good agreement with the experimental data.