| 초록 |
The effects of Ti on the high temperature oxidation of Ni-based superalloys were investigated by cyclic oxidation at $850^{ circ}C$ and $1000^{ circ}C$ . The oxide scale formed at $850^{ circ}C$ consists of $Cr_2O_3$ , $Al_2O_3$ , and $NiCr_2O_4$ layers, while a continuous $Al_2O_3$ layer was formed at $1000^{ circ}C$ . The oxidation rate of the alloy with higher Ti content was higher than the alloy with less Ti content at $850^{ circ}C$ , possibly due to the increase in the metal vacancy concentration in the $Cr_2O_3$ layer involved by incorporation of $Ti^{4+}$ . However, Ti improved the oxidation resistance of the superalloy at $1000^{ circ}C$ by reducing oxygen vacancy concentration in $Al_2O_3$ layer. |
