Microstructural characterization of Ce-TZP/Al₂O₃ after degradation in water

Figures & data

Figure 1. Typical SEM micrographs of sintered (a) Ce-TZP/Al₂O₃ and (b) Y-TZP specimens.

Table 1. Microstructural characteristics of Ce-TZP/Al₂O₃ investigated in this study. Y-TZP specimens were also prepared for comparison.

	Ce-TZP/Al2O3	Y-TZP
Density/g/cm^3	5.51 ± 0.02	5.94 ± 0.03
Relative density/%	99.1 ± 0.4	98.2 ± 0.5
Size of ZrO2 grains/μm	1.1	0.6
Size of Al2O3 grains/μm	0.8	-

Figure 2. (a) Thin section taken from the surface region of Ce-TZP/Al₂O₃ specimen before hydrothermal treatment. (b) TEM micrograph of the area indicated with a square in (a). (c) Diffraction pattern of the ZrO₂ grain near surface (circled).

Figure 3. XRD diffraction patterns of (a) Ce-TZP/Al₂O₃ and (b) Y-TZP specimens before and after hydrothermal treatments for various times.

Figure 4. Amount of m-phase after hydrothermal treatment for various times.

Figure 5. Fracture surfaces of (a) Ce-TZP/Al₂O₃ specimen after hydrothermal treatment for 360 h, and (b) Y-TZP specimens after hydrothermal treatment for 24 h.

Figure 6. (a) Thin section taken from the surface region of Ce-TZP/Al₂O₃ specimen after hydrothermal treatment for 360 h. (b) TEM micrograph in the surface region as indicated with a square in (a). (c) TEM micrograph at higher magnification of the ZrO₂ grain indicated with a square in (b). (d) Diffraction pattern of the ZrO₂ grain shown in (c).

Figure 7. Weibull plots of (a) Ce-TZP/Al₂O₃ and (b) Y-TZP specimens before and after hydrothermal treatment.

Figure 8. Biaxial strength of Ce-TZP/Al₂O₃ and Y-TZP specimens as a function of m-phase content.

Figure 9. Loading-unloading-reloading curves of Ce-TZP/Al₂O₃ specimen (a) before and (b) after hydrothermal treatment. The time for hydrothermal treatment of the specimen in (b) was 120 h.

Figure 10. (a) Thin section taken from the surface region of Y-TZP specimen after hydrothermal treatment for 24 h. (b) TEM micrograph in the surface region as indicated with a square in (a).

Table 2. Hydrothermal resistance of the Ce-TZP/Al₂O₃ and Y-TZP prepared in this study; corresponding data can be found in the figures indicated in brackets.

	Ce-TZP/Al2O3	Y-TZP
Time of hydrothermal treatment/h	360	24
m-phase content/%	28 (Figure 3a, Figure 4)	60 (Figure 3b, Figure 4)
Remaining strength after degradation/%	88% (Figure 7a, Figure 8)	60% (Figure 7b, Figure 8)
Surface charging layer (SEM)/μm	~1 (Figure 5a)	5 (Figure 5b)
Surface transformation layer (TEM)/μm	>12 (Figure 6)	>3 (Figure 10)