This study focused on improving the phase stability and mechanical properties of yttria-stabilized zirconia (YSZ), commonly utilized in gas turbine engine thermal barrier coatings, by incorporating Gd2O3, Er2O3, and TiO2. The addition of 3-valent rare earth elements to YSZ can reduce thermal conductivity and enhance phase stability while adding the 4-valent element TiO2 can improve phase stability and mechanical properties. Sintered specimens were prepared with hot-press equipment. Phase analysis was conducted with X-ray diffraction (XRD), and mechanical properties were assessed with Vickers hardness equipment. The research results revealed that, except for Z10YGE10T, most compositions predominantly exhibited the t-phase. Increasing the content of 3-valent rare earth oxides resulted in a decrease in the monoclinic phase and an increase in the tetragonal phase. In addition, the t(400) angle decreased while the t(004) angle increased. The addition of 10 mol% of 3-valent rare-earth oxides discarded the t-phase and led to the complete development of the c-phase. Adding 10 mol% TiO2 increased hardness than YSZ.

1. Introduction
2. Experimental
3. Results and Discussion
    3.2 Calculate porosity of microstructure
    3.3 Vickers hardness
4. Conclusion
Acknowledgement

• 최용석(한국세라믹기술원 이천분원 엔지니어링 소재센터, 고려대학교 신소재공학과) | Yong Seok Choi
• 이계원(한국세라믹기술원 이천분원 엔지니어링 소재센터, 고려대학교 신소재공학과) | Gye Won Lee (Korea Institute of Ceramic Engineering and Technology, Engineering Materials Center, Icheon 17303, Republic of Korea, Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea)
• 남산(고려대학교 신소재공학과) | Sahn Nahm (Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea)
• 오윤석(한국세라믹기술원 이천분원 엔지니어링 소재센터) | Yoon suk Oh (Korea Institute of Ceramic Engineering and Technology, Engineering Materials Center, Icheon 17303, Republic of Korea) Corresponding Author