Characterization of Layers Produced by Boriding and Boriding-PVD on AISI D2 Tool Steel

Abstract

Boride layers with high hardness and wear resistance were produced on AISI D2 tool steel by thermo-reactive treatment using borax with the addition of 10 wt. % aluminum. Subsequently, PVD treatments were performed on the borided layer. The samples were characterized using optical microscopy, scanning electron microscopy, X-ray diffraction, micro-hardness testing, and free-ball micro-abrasive wear test. The boriding treatment time was 4 h, followed by cooling in oil or air. The average thickness of the borided layers was 120 μm with a hardness ranging from 1400 to 1700 HV. The micro-abrasive wear tests were performed using an abrasive solution of silicon carbide. All layers produced exhibited a wear resistance much higher than that of the substrate. Samples with duplex PVD plus boriding treatments yielded the best wear performance, followed by the borided steel samples, and finally, the untreated quenched and tempered samples.