Properties Of Zirconia Ceramics

Zirconia ceramics (ZrO2), with high melting point, high hardness, excellent wear resistance, as an insulator at normal temperature, and at high temperature has conductive properties. Pure ZrO2 is white, yellow or gray when containing impurities, and generally contains HfO2, which is not easy to separate. Zirconia is usually purified from zirconium ore.

Zirconia has three kind of crystals: low-temperature monoclinic crystal (m-ZrO2), medium-temperature tetragonal crystal (t-ZrO2), high-temperature cubic crystal (c-ZrO2), the above three crystals exist in different temperature ranges, and can be converted to each other.

Zirconia ceramics is a new type of high-tech ceramics, in addition to high strength, hardness, high temperature resistance, acid and alkali corrosion resistance and high chemical stability, at the same time with scratch resistance, no signal shielding, excellent heat dissipation performance, while machinability, good appearance effect, suitable for mass production.

1. High melting point

The melting point of zirconia is 2715℃, and the high melting point and chemical inertness make zirconia a good refractory material.

2. high hardness, good wear resistance

Zirconia ceramics have higher hardness and better wear resistance. From the specific data, the Mohs hardness of zirconia ceramics is about 8.5, which is very close to the Mohs hardness of sapphire 9.

3. the strength and toughness are relatively large

Zirconia ceramics have a high strength (up to 1500MPa).

4. low thermal conductivity, low expansion coefficient

The thermal conductivity of zirconia is the lowest in common ceramic materials (1.6-2.03W/ (m.k)), and the coefficient of thermal expansion is close to that of metal. Therefore, zirconia ceramics are suitable for structural ceramic materials.

5. good electrical performance

The dielectric constant of zirconia is 3 times that of sapphire, the signal is more sensitive, and it is more suitable for fingerprint recognition patches. Based on the perspective of shielding efficiency, zirconia ceramics, as a non-metallic material, have no shielding effect on electromagnetic signals, and will not affect the internal antenna layout, which can be easily integrated and adapt to the 5G era.