Title: Pack-boriding of AISI P20 steel: estimation of boron diffusion coefficients in the Fe₂B layers and tribological behaviour

Authors: M. Keddam; M. Elias-Espinosa; M. Ortiz-Domínguez; I. Simón-Marmolejo; J. Zuno-Silva

Addresses: Laboratoire de Technologie des Matériaux, Faculté de Génie Mécanique et Génie des Procédés, USTHB, B.P. No. 32, 16111 El-Alia, Bab-Ezzouar, Algiers, Algeria ' Instituto Tecnológico y de Estudios Superiores de Monterrey-ITESM, Campus Santa Fe, Av. Carlos Lazo No. 100, Del. Álvaro Obregón, CP. 01389, D. F., México ' Universidad Autónoma del Estado de Hidalgo, Escuela Superior de Ciudad Sahagún-Ingeniería Mecánica, Carretera Cd. Sahagún-O tumba s/n, Zona Industrial CP. 43990, Hidalgo, México ' Universidad Autónoma del Estado de Hidalgo, Escuela Superior de Ciudad Sahagún-Ingeniería Mecánica, Carretera Cd. Sahagún-O tumba s/n, Zona Industrial CP. 43990, Hidalgo, México ' Universidad Autónoma del Estado de Hidalgo, Escuela Superior de Ciudad Sahagún-Ingeniería Mecánica, Carretera Cd. Sahagún-O tumba s/n, Zona Industrial CP. 43990, Hidalgo, México

Abstract: In the present study, the AISI P20 steel was pack-borided in the temperature range of 1,123-1,223 K for treatments times between 2 and 8 h. A new kinetic model based on the integral method was used to estimate the boron diffusion coefficients in the Fe₂B layers. As a result, the activation energy for boron diffusion in the AISI P20 steel was estimated as 194.3 kJ mol⁻¹. This value of energy was compared with the literature results. Furthermore, to validate experimentally the present model, two additional boriding conditions were used. The morphology of cross-sections of borided samples was examined by scanning electron microscopy. The formation of a single boride layer was confirmed by x-ray diffraction analysis. The Daimler-Benz Rockwell-C indentation technique was used to evaluate the cohesion of boride layers on the surface of AISI P20 steel. Finally, the scratch and pin-on-disc tests for wear resistance were carried out by means of a LG Motion Ltd and a CSM tribometer respectively under dry sliding conditions.

Keywords: incubation time; diffusion model; activation energy; growth kinetics; cohesion; wear.

DOI: 10.1504/IJSURFSE.2017.088997

International Journal of Surface Science and Engineering, 2017 Vol.11 No.6, pp.563 - 585

Received: 08 Jun 2017
Accepted: 25 Aug 2017
Published online: 03 Jan 2018 *

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