thermodynamic investigation of pack aluminizing process of pure titanium

in this research, aluminizing packs containing naf and nh4cl activators were used for aluminizing of pure titanium samples at 1100 ºc. the results showed that the layers of tial3, tial2, γ-tial, α2-ti3al, and α-solid solution are formed on titanium samples in both cases. however, the weight gain and the thickness of tial3 layer in treated samples with nh4cl activator are greater than those when naf activator is used. using a thermodynamic model showed that the partial pressures of aluminum-containing gases when nh4cl is used are much greater and accordingly, the experimental results were justified.