Pack Siliconizing of Ti6Al4V Alloy

Abstract

In this study, it was aimed to produce titanium silicide layer on Ti6Al4V by a simple, cheap and efficient method of pack siliconizing. Siliconizing was performed in a pack containing a mixture composed of SiO2 powder as siliconizing source, pure Al powder as a reducer for siliconizing, NH4Cl as an activator and Al2O3 powder as filler, at 1000 degrees C for 8, 10 and 12 hours in open atmospheric furnace. Optical microscope and SEM-EDS studies indicate that the morphology of silicide layers has smooth, dense and layered nature. The presence of phases, confirmed by XRD analyses, reveals that the silicide layers formed at 1000 degrees C are composed of TiSi2, Ti3Si5, TiN, TiO2 and SiO2 compounds. Silicide layer thickness was increased with increasing process time and ranged from 7.5 to 9.0 mu m. Hardness of silicide layers, measured by Vickers indentation, is over 2100 HV.