OXIDATION RESISTANCE OF TWO TiB_2-BASED CERMETS

摘要

The oxidation kinetics of two TiB_2 cermets containing Fe-Ni-Al-ferritic and stainless steel binder phases has been determined in air at temperatures in the range of 700-l000deg.C for up to 70 h. Mass gain records as a function of time and temperature showed two kinetic ranges, a parabolic one up to 775deg.C and a linear one above 800deg.C. Activation energies were observed to be l53-l65 and ll0-ll8 kJ.mol~-l for the parabolic and linear ranges, respectively. The oxidation products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results are compared to those reported for similar materials.