Nitridation study of reaction-bonded silicon nitride in situ by High temperature X-Ray difraction

摘要

The reaction-bonded silicon nitride (RBSN) nitri- ding process has been studied using a high tem- perature X-ray diffractometer (HT-XRD) under isothermal conditions in the temperature interval 1300-1400 deg.C. with HT-XRD, the nitridation reaction and phases formed could be monitored almost instantaneously at temperature. The experi- mentally observed kinetics of the nitriding reaction were found to be in fair agreement with a theoret- ical model which predicts that the nitriding reaction occurs predominantly by Knudsen diffusion of nitro- gen molecules through channels in a layer of growing Si_3N_4. However, no single rate layer is likely to describe the whole nitridation process.