Effect of Different Nucleation Temperatures on the Microstructural Development of α-SiAlON Ceramics

Abstract

α-SiAlON ceramics with elongated grains were previously observed in different studies. Sintering conditions are known to have a significant role on the microstructural development. By the nucleation treatment application during sintering, α-SiAlON with needle-like microstructure can be achieved also in a nitrogen rich composition and utilizing commercial α-Si 3 N 4 , whereas typical equiaxed grains are formed if the nucleation was not applied prior to growth in the same system. In this study, Ca-Ce containing multication systems for two different compositions are chosen to combine the facility of Ce for elongated grain formation with the convenient separation of maximum rates for nucleation and grain growth of Ca. The effects of different nucleation temperatures are examined to understand the microstructural development behaviour of α-SiAlON grains in this system.

Cost‐effective fabrication of α‐SiAlON ceramics with CeO2 addition for cutting tool applications

“…In addition, a small number of Ce‐α‐SiAlONs were also formed via the addition of 1‐wt.% Y‐α‐SiAlON seeds utilizing plasma‐activated sintering, as mentioned in Wang et al.’s work 24 . Furthermore, Kushan and Mandal's results revealed α‐SiAlON ceramics with needlelike grains could be obtained for Ca–Ce containing multi‐cation systems by controlling nucleation temperature, 25 and the fracture toughness of the material was enhanced because of crack deflection, bridging, and grain pullout mechanisms 26 …”

“…The samples were sintered eventually at 1820°C for 2 h under a nitrogen pressure of 5 MPa. In addition, a heat preservation was carried out at 1600°C for 1 h before heating up to the maximum temperature to control nucleation temperature and slow nucleation rate 25,30 …”

“…In addition, a heat preservation was carried out at 1600 • C for 1 h before heating up to the maximum temperature to control nucleation temperature and slow nucleation rate. 25,30…”

“…In addition, a small number of Ce-α-SiAlONs were also formed via the addition of 1-wt.% Y-α-SiAlON seeds utilizing plasma-activated sintering, as mentioned in Wang et al's work. 24 Furthermore, Kushan and Mandal's results revealed α-SiAlON ceramics with needlelike grains could be obtained for Ca-Ce containing multi-cation systems by controlling nucleation temperature, 25 and the fracture toughness of the material was enhanced because of crack deflection, bridging, and grain pullout mechanisms. 26 However, most former studies merely focused on the influence of CeO 2 on the phase assemblage and microstructure of SiAlON ceramics, to the best of our knowledge, without a detailed analysis and discussion on the mechanical behaviors.…”