Mechanical properties and kinetics of boride layers on AISI D2 steel produced by plasma paste boriding

Abstract

In the present study, the AISI D2 steel has been treated by the plasma paste boriding process using a gas mixture of 70% H2-30% Ar with 70% of borax and 30% SiC. The boriding treatment has been carried out at 700, 750 and 800 °C for an exposure time of 3 to 7 h. The plasma paste borided samples have been investigated by various techniques such as scanning electron microscopy, optical microscopy, XRD analysis, micro-hardness Vickers and the rockwell-C adhesion tests. The fracture toughness has also been measured on the plasma paste borided samples under different values of indentation load. From a kinetic point of view, the boride layers have obeyed the parabolic growth law. The value of boron activation energy for AISI D2 steel has been estimated as 130 kJ mol–1 using our experimental results. In addition, this obtained activation energy has been compared to the literature data.