A model for studying the kinetics of the formation of Fe2B boride layers at the surface of a gray cast iron

✍ Scribed by M. Keddam; R. Chegroune

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 639 KB
• Volume: 256
• Category: Article
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2010.03.048

✦ Synopsis

The present work estimates, using a kinetic model, the growth kinetics of Fe 2 B boride layers generated at the surface of a gray cast iron via the powder-pack boriding considering three different temperatures (1173, 1223 and 1273 K) and four treatment times (2, 4, 6 and 8 h). By the use of the mass balance equation at the (Fe 2 B/substrate) interface under certain assumptions and considering the effect of the boride incubation time, it was possible to estimate the corresponding parabolic growth constant in terms of two parameters ˛ C Fe 2 B up and ˇ(T) depending on the boron content in the Fe 2 B phase and on the process temperature, respectively. The mass gain at the material surface and the instantaneous velocity of the (Fe 2 B/substrate) interface were also estimated. A fairly good agreement was observed between the experimental parabolic growth constants taken from a reference work (Campos-Silva et al., Characterization of boride layers formed at the surface of gray cast irons, Kovove Mater. 47 (2009) 1-7.) and the simulated values of the parabolic growth constants. Furthermore, the boride layer thicknesses were predicted and experimentally verified for three process temperatures and four treatment times.