Characterization and Boronizing Kinetics of EN-GJL-250 Lamellar Gray Cast Iron

Abstract

Received: 18 August 2019 Accepted: 5 November 2019 The aim of the present study is to generate the boride coatings at the surface of the lamellar gray cast iron (EN-GJL-250). This material was hardened by pack-boriding in the powders mixture of 50% B4C, 49.5% Al2O3 and 0.5% AlF3 at 800, 900 and 1000°C for 4, 6 and 8 h. The produced borided layers were characterized by Scanning electron microscopy (SEM) and XRD analysis. The boriding kinetics of EN-GJL-250 lamellar gray cast iron was also investigated. Based on the experimental data, the value of activation energy for boron diffusion was calculated as 163.86 kJ mol-1 for the EN-GJL250 cast iron by using the integral diffusion model. The regression model based on the design of experiments (DOE) was also employed in order to predict the total boride layer thickness as a function of boriding parameters (the treatment time and the boriding temperature). The experimental values of total boride layer thickness were in agreement with the results from the regression model.