M. ELIAS-ESPINOSA, M. ORTIZ-DOMÍNGUEZ, MOURAD KEDDAM, M. A. FLORES-RENTERÍA, O. DAMIÁN-MEJÍA, J. ZUNO-SILVA, J. HERNÁNDEZ-ÁVILA, E. CARDOSO-LEGORRETA, A. ARENAS-FLORES, GROWTH KINETICS OF THE FE2B LAYERS AND ADHESION ON ARMCO IRON SUBSTRATE, JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE, 2952?Volume 23(8) August 2014 ISSN: 1059-9495 (PRINT) 1544-1024 (ONLINE) IMPACT FACTOR. 0.92, DOI: 10.1007/S11665-014-1052-2
In this work, a kinetic model was suggested to evaluate the boron diffusion coefficient in the Fe2B layers grown on the Armco iron substrate by the powder-pack boriding. This thermochemical treatment was carried out in the temperature range of 1123-1273 K for treatment times ranging from 2 to 8 h. The boron diffusion coefficient in the Fe2B layers was estimated by solving the mass balance equation at the (Fe2B/substrate) interface with an inclusion of boride incubation time. To validate the present model, the simulated value of Fe2B layer thickness was compared with the experimental value obtained at 1253 K for a treatment time of 5 h. The morphology of Fe2B layers was observed by SEM and optical microscopy. Metallographic studies showed that the boride layer has a saw-tooth morphology in all the samples. The layer thickness measurements were done with the help of MSQ PLUS software. The Fe2B phase was identified by x-ray diffraction method. Finally, the adherence of Fe2B layers on the Armco iron substrate was qualitatively evaluated by using the Daimler-Benz Rockwell-C indentation technique. In addition, the estimated value of boron activation energy was compared to the literature data.