Si₃N₄ (Silicon Nitride) has good oxidation resistance and hence potential in many applications where strong resistance to environment-accelerated oxidation is required.  Examples include biological implantation and high temperature environment.  The rate of oxidation at Si₃N₄ surface can be monitored by obtaining the depth profile of SiO₂ using Auger electron spectroscopy (AES) and ion sputtering.  By comparing the SiO₂ depth profiles of treated and untreated samples (a native SiO₂ layer always exists), the rate of oxidation can be determined.