Microhardness characterization of structures obtained by iron–silicon solid-state reaction

Microhardness measurements of structures, obtained by a solid-state reaction of iron with silicon are undertaken. The experimental results support the finding that the indentation size effect (ISE) appears in the microhardness-depth profile whenever the indentor crosses an interface. When modelling the experimental microhardness-depth profiles of the multilayered structures, an analytical expression for the coefficient giving the contributions of the film and the substrate hardnesses to the composite one is offered. A value of 9.60 GPa is obtained for the microhardness of β-FeSi2 thin layer. On the base of the microhardness-depth profiles measurement conclusions about the solid-state reaction process are drawn.