Dependence between the Boron Surface Concentration and the Growth Kinetics of Boride Layers in AISI 4140 Steels

Abstract:

Article Preview

The present work estimated the growth kinetics of Fe2B layers formed at the surface of AISI 4140 steels. The thermochemical treatment was applied in order to produce the Fe2B phase, considering temperatures of 1123, 1173, 1223 and 1273 K with five exposure times (2, 4, 5, 6, and 8 h), using a 4 mm thick layer of boron carbide paste over the material surface. The growth of boride layers was described by the mass balance equation between phases in thermodynamic equilibrium, assuming that the growth of boride layers obeys the parabolic growth equation and the boron concentration at the interfaces remains constant. Also, the boron diffusion coefficient at the Fe2B ( ) was established as a function of boriding temperature. Likewise, the parabolic growth constant (k), the instantaneous velocity (v) of the Fe2B/substrate interface and the weight-gain of borided steels were established as a function of the parameters and , which are related to the boride incubation time ( ) and boron surface concentration ( ), respectively.

Info:

Periodical:

Defect and Diffusion Forum (Volumes 297-301)

Edited by:

Andreas Öchsner, Graeme E. Murch, Ali Shokuhfar and João M.P.Q. Delgado

Pages:

294-299

DOI:

10.4028/www.scientific.net/DDF.297-301.294

Citation:

M. Ortíz-Domínguez et al., "Dependence between the Boron Surface Concentration and the Growth Kinetics of Boride Layers in AISI 4140 Steels", Defect and Diffusion Forum, Vols. 297-301, pp. 294-299, 2010

Online since:

April 2010

Export:

Price:

$35.00

In order to see related information, you need to Login.

In order to see related information, you need to Login.