A Simple Kinetic Model for the Growth of Fe2B Layers on AISI 1026 Steel During the Powder-pack Boriding

Abstract

This work focused on the determination of boron diffusion coefficient through the Fe

Modeling of the Growth Kinetics of Boride Layers in Powder-Pack Borided ASTM A36 Steel Based on Two Different Approaches

“…ese phases consist of orthorhombic and tetragonal lattices (bodycentred), respectively. One basic advantage of boride layers is that they can reach high hardness values (between 1800 and 2000 HV), kept at high temperatures [1][2][3][4]. Abrasion and adhesion wear are forms of wear by contact between a particle and solid material, being the characteristic result of almost all types of mechanical stress.…”

“…However, the most frequently used method in industry is the powder-pack boriding, which demands a low investment cost of equipment and an easy handling. From a kinetic point of view, several approaches [3,[5][6][7] were developed in the objective of optimizing the thicknesses of borided layers in order to meet the functional requirements during industrial use of borided steels. Some of these models that estimate the thickness of the monolayer (Fe 2 B) or a double layer (FeB-Fe 2 B) are based on the solution of Fick's second law without time dependent (∇ 2 C Fe 2 B (x) � 0 ⟶ steady state) [3, 6, 7, 16-18, 20-22, 24-26, 30] and some others on the solution of Fick's second law with time dependent (zC Fe 2 B(x, t)/zt � D Fe 2 B z 2 C Fe 2 B (x, t)/zx 2 ⟶ non-steady state) [5,24,27,28,31,33].…”

Kinetics of Formation of Fe2B Layers on AISI S1 Steel

“…where Q is the activation energy for boron diffusion (kJmol -1 ), D 0 represents a pre-exponential constant (m 2 s -1 ) and T is the absolute temperature in Kelvin. Simulated value (µm) 6 Simulated value (µm) 7 Simulated value (µm) 8 Simulated value (µm) Equation (18) 1173 K for 3. Table 4 provides the expressions of Fe 2 B layer thickness as a function of boriding parameters derived for four diffusion models with Equation (18) valid for the integral method.…”

“…From a kinetic point of view, several approaches have beeen developed to study the kinetics of formation of Fe 2 B layers on Armco iron and steels as substrates [3][4][5][6][7][8][9][10][11][12] .…”

“…They introduced the β(T) parameter that depends on the boriding temperature. Flores-Rentería et al 8 have modelled the kinetics of formation of Fe 2 B layers on AISI 1026 steel by using a kinetic model. In their model, they introduced a kinetic parameter called ε which is independent on the boriding temperature with a linear boron concentration profile in the Fe 2 B layer.…”