Boride Layer Growth Kinetics Of Aisi H13 Steel Borided With Nano-Sized Powders

Abstract

Growth kinetics of boride layers in AISI H13 steel was investigated using the pack bonding method at temperatures of 1073, 1173 and 1273 K (800 degrees C, 900 degrees C and 1000 degrees C) for periods of 2, 4 and 6 h with nano-sized boron (NB) and micron-sized Ekabor II powders as bonding agents. The total thickness of the boride layer (including both FeB and Fe2B) after boriding at 1273 K (1000 degrees C) for 6 h was 103.8 gm and 96.5 mu m for the NB and Ekabor II specimens, respectively. X-ray diffraction analysis of the boride layers on the surfaces borided with NB and Ekabor II revealed the presence of FeB and Fe2B phases with sawtooth morphology. The FeB/Fe2B volume ratio was higher in the specimens borided with NB. The thickness of the boride layer (FeB + Fe2B) increased with the increasing boriding temperature and time. The FeB layer in the NB specimen displayed a (002) preferred orientation.