Abstract

ELIAS-ESPINOSA, M. et al. Diffusional Growth Kinetics Analisys of Fe2B Layers Applied During the Coating Powder-Pack Boriding Process on an AISI 1026 Steel. Nova scientia [online]. 2015, vol.7, n.14, pp.74-101. ISSN 2007-0705.

In the present study, a mathematical model was proposed for analyzing the growth of Fe2B layers formed on AISI 1026 steel by the pack-boriding process. This model was based on solving the mass balance equations of the (Fe2B/Fe) interface to evaluate the boron diffusion coefficients through the Fe2B layers in the temperature range of 1123-1273 K. The boride incubation time for the Fe2B phase was included in the present model. The suggested model was validated experimentally at a temperature of 1253 K for a treatment time of 7 h. Furthermore, the generated boride layers were analyzed by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis. The Daimler-Benz Rockwell-C indentation technique was used to qualitatively evaluate the adherence of the layer on the substrate. For practical use, an iso-thickness diagram was also proposed as a function of treatment time and temperature. The boron activation energy for AISI 1026 steel was found to be equal to 178.4 kJ mol-1 on the basis of our experimental results.

Keywords : boriding; incubation time; diffusion model; growth kinetics; activation energy; adherence.

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