SiAlON ceramics have complicated chemistry and should be considered a group of alloys with diverse characteristics. It is generated when silicon nitride (Si3N4) aluminium oxide (Al2O3) and aluminium nitride (AlN) react together. If sintering aids such as Dysprosium oxide are added to the initial composition fully dense polycrystalline bodies can be produced through pressureless sintering.Inter-granular phase composition and structure may be modified by dopants and sintering conditions which significantly impact the characteristics of SiAlON ceramics. The focus of this study was concentrated on the nature of densification and nature of the phases that appeared in SiAlON. It was found that the volume and density of all the specimens considerably reduced and enhanced respectively owing to sintering at elevated temperatures. The XRD results showed various phases as per their relative intensities which indicates densification will alter different properties especially mechanical and thermal properties.