Statistical Evaluation of Repeatability Analyses of SiAlON Production Process

SiAlON ceramics are potential for many applications due to good mechanical and high temperature properties. In spite of their excellent properties, the utilization of SiAlONs has remained limited until today due to the high cost of raw materials and processing. Traditionally, high quality pure ?-Si3N4 powder is used instead of ß-Si3N4 powder due to its higher sintering activity in SiAlON production. However, fine ?-Si3N4 powders are very high in cost and this is a key determinant parameter for large-scale applications. In order to widen commercial use of SiAlON ceramics, low cost manufacturing of SiAlONs with satisfactory mechanical properties is necessary. In this study, the repeatability of SiAlON ceramics produced from low cost ß-Si3N4 powder with gas pressure sintering method was investigated. The samples produced four sets of gas pressure sintering furnace by independently. Statistical analyses of Vickers hardness and indentation fracture toughness data was carried out by MİNİTAB program. The results coincided with the microstructural images. The results showed that the majority of microstructures are similar and in all cases, the samples showed statistically little variation in hardness and fracture toughness.