DEVELOPMENT OF NI-BASED SUPERALLOY BY PACK CEMENTATION PROCESS.

Abstract

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 1120oC 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 Al1.1Ni0.9.