DEVELOPMENT OF NI-BASED SUPERALLOY BY PACK CEMENTATION PROCESS

The aim of this research was to improve the properties of Inconel 600 by diffusion coating process. In this study, Si and Al, and  Al, Si  and Y₂O₃ were simultaneously deposited by diffusion into Inconel 600 using pack cementation process at 1120^oC for the different time (2,4,6,8)hr. The pack powder mixture consists of 18Al–8Si–2NH₄Cl–72Al₂O₃(wt.%) for silicon modified aluminde diffusion coating  and replaced  1%  from Al₂O₃   by  Y₂O₃ for yttria doped  silicon modified aluminide diffusion coating. The results show  that the coatings microstructure had consists of two layers: outer layer and inter-diffusion zone. The coating thickness increase with increase the time of coating process up to 234µm  and 153µm at 8hr for two type of coatings. The micro-hardness value decrease from outer layer toward the core of the substrate .The high microhardness value is 823 Kg/mm² at 8hr for type I and 902 Kg/mm² at 8hr for type II of coatings. The X-ray results shows different inter-metallic compound formed after coatings are Ni₂Al₃, Fe₃Si , Ni₂Si, Ni₃Si₂,YNi₁₀Si₂ and Al_1.1Ni_0.9.