Pushing of Interstitial Elements in the Transition Zone under the Growing Diffusion Layers

Abstract

The kinetics of diffusion of interstitial elements on the example of diffusion saturation with boron and silicon iron- carbon matrix (- iron) was considered . The layers of intermetallic Fe - B - Si are formed and grow in diffusion saturation , and carbon is pushed deep into the matrix. Linear , parabolic and logarithmic laws of motion of the interface boundary between the intermetallic layers and  steel  matrix was considered and solved the problem of the diffusion redistribution of carbon in the transition zone. Found that in all these cases is due to pushing of carbon  its concentration are increased at the interphase boundary . In case: a) the linear moving  of the interphase boundary carbon concentration at the interphase boundary is proportional to the thickness of protective coatings; b) the parabolic moving  of the interphase boundary carbon concentration at the boundary remains constant; c) the logarithmic moving  of the interphase boundary carbon concentration at the interphase boundary decreases with time.