What are the advantages of zirconia ceramics over alumina ceramics?

Ceramic toughness: The toughness of zirconia ceramics is 4 times that of alumina ceramics. At the same time, when zirconia is dropped freely from a height of one meter, there will be some gaps, and the alumina will be broken.
Density: The density of zirconia ceramics is twice that of alumina ceramics. In contrast, zirconia has better compressive properties.
Friction coefficient: The friction coefficient of zirconia ceramics is only half of that of alumina ceramics, and the elastic modulus and hardness are mainly considered in the actual use process.
Density and surface finish: The density of zirconia ceramic structural parts is higher than that of alumina ceramics. After grinding, the surface finish is higher, up to Ra0.2 or more, mirror-like, extremely smooth, and has a smaller friction coefficient.
The lattice of zirconia ceramics is stable at high temperatures, and the lattice phase is damaged once it reaches normal temperatures. Therefore, 94.8% of zirconia reaches a stable state at room temperature, and a 5.2% stabilizer must be added. The powder is dry-pressed and sintered at 1560 ℃, the hardness and toughness will exceed 99% alumina ceramics, and its wear resistance and impact resistance will exceed 99% alumina ceramics. If no stabilizer is added, the ceramic is easy to crack, so zirconia balls are used as abrasive materials because they have great hardness and toughness.
What are the advantages of zirconia ceramics over alumina ceramics？