In this study, we investigated the synthesis of pack cemented coating on two metallic materials (304 & 316L) in order to form silicon compounds on their surface at lower temperatures (800,900 &950˚C) to avoid sintering of the pack and adhesion of material to the samples surface.In our investigation silicon was used as a master alloy and alumina (Al2O3) as a filler material. Also ammonium chloride was used as an activator with different weight percentage (5,7 &10%) ,in order to increase the efficiency of the coating layer formation process. Silicon zing of two alloys which are 304 & 316L by pack cementation process according to light optical microscope examination (LOM), the coating layer formation is a temperature and activator weight percentage dependent process, which means that it is a diffusion controlled reaction. Thus the thickness of sample silicon zed with pack content 10% activator at 950˚C is higher than the sample silicon zed with pack content 7% and 5% activator and these samples have higher thickness than samples coated at 900˚C and 800˚C at same conditions. The average coating thickness obtained by silicon zing process at 4hr by using different activator weight percentage for two selective alloys are:1-8.520 -129.390 am for 304 st.st alloy. 2-75.929 -192.592 μm for 316L st.st alloy.