The production of functionally graded SiAlON ceramics by tape casting method

SiAlON ceramics have continuously been an interest area in structuraladvanced ceramics, due to their high temperature mechanical and thermalproperties. In this thesis study, at two different cations (Y+3 ve Sm+3) addition,functionally graded α/β-SiAlON ceramics production and characterization wereaimed by using organic and water based tape casting process. The slurry rheologyand final properties of functionally graded SiAlONs were investigated. Therheological properties of organic and water based slurries were measured by usingviscosimeter with cylindrical cone. Organic slurries were observed to showpseudoplasticity with low thicksotropy and water based slurries showed a driftfrom pseudoplasticity by becoming nearer to Newtonian behavior at lower solidand polymer loadings. The produced functionally graded SiAlONs werecharacterized by using Archimedes density, micro hardness, x-ray diffraction andscanning electron microscopy (SEM). As a result of these analysis, hardness andphase distribution were found to be changed as functionally graded. These resultswere supported by x-ray diffraction and micro structural analysis.Keywords: SiAlON, Functionally Graded Materials (FGMs), Tape Casting,Pseudoplastic