Pack Siliconizing of Ti6Al4V Alloy

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°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°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 μm. Hardness of silicide layers, measured by Vickers indentation, is over 2100 HV.