Ionic interdiffusion as interaction mechanism between Al and Si3N4 |
| |
| Authors: | Esmaeil Adabifiroozjaei Pramod Koshy Fahimeh Emadi Sajjad S Mofarah Hongyang Ma Ebad Rastkerdar Sean Lim Richard F Webster David RG Mitchell Charles C Sorrell |
| |
| Affiliation: | 1. Research Center for Functional Materials (RCFM), National Institute for Materials Science (NIMS), Tsukuba, Japan;2. School of Materials Science and Engineering, University of New South Wales, Sydney, NSW, Australia;3. Department of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran;4. Faculty of Mechanical Engineering, Department of Materials Engineering, University of Tabriz, Tabriz, Iran;5. Electron Microscope Unit, University of New South Wales, Sydney, NSW, Australia;6. Electron Microscopy Centre, AIIM, University of Wollongong, Wollongong, NSW, Australia |
| |
| Abstract: | Al-Si3N4 couples were heat-treated at 850-1150°C for 250 hours. The thickness of the interacted area was measured by scanning electron microscopy (SEM) and scanning/transmission electron microscopy (TEM/STEM). The interaction rate increases exponentially with inverse temperature, with an activation energy of 194.23 kJ/mol and diffusion pre-coefficient of 5 × 10?9 m2/s, indicating that the interaction is diffusion-dependent. As the results showed, the interfacial area is comprised of Al alloy channels, Si precipitates, and AlN grains. Al-Si transfer through the solid solution (Si3-xAlxN4-y) at the interface of Al alloy and β-Si3N4 grains controls the kinetic of the interaction. When concentration of Al in solid solution exceeds a certain amount, it undergoes a topotactic phase transformation to form Al1-xSixN1+y (viz., AlN). Next, the Al1-xSixN1+y grains detach from the β-Si3N4 grains and subsequently new Al-Si3N4 interfaces are established. These interfaces repeat the interaction process, continuing until all the reactant is depleted. Thus, the interaction kinetics consist of a sequence of associated parabolic stages, precluding the observation of parabolic kinetics. |
| |
| Keywords: | Al-Si interdiffusion Al-Si3N4 interface kinetics topotactic transformation |
|
|
