What are the special properties of zirconia ceramics? What are the main applications? What are the advantages compared with metal materials?

Properties of zirconia ceramics: pure ZrO2 _ 2 is white, yellow or gray when it contains impurities, and generally contains HfO2 _ 2, which is difficult to separate. The proven zirconium resources in the world are about190,000 tons, and zirconia is usually prepared by purifying zirconium ore. There are three crystal forms of pure ZrO2*** at atmospheric pressure: monoclinic zirconia (m-ZrO2), tetragonal zirconia (t-ZrO2) and cubic zirconia (c-ZrO2), which exist in different temperature ranges and can be transformed into each other:

Temperature density

Monoclinal zirconia

Tetragonal zirconia1200-2370℃ 6.10g/cc

Cubic zirconia (c-ZrO2) >: 6.27g/cm3 at 2370℃

The above three crystalline states have different physical and chemical properties. In practical application, different types of zirconia ceramics are usually made by adding different types of stabilizers, such as partially stabilized zirconia (PSZ). When the stabilizers are CaO, MgO and Y2O3, they are expressed as Ca-PSZ, Mg-PSZ, Y-PSZ, etc. Tetragonal zirconia composed of metastable t- ZrO2 is called tetragonal zirconia polycrystal (TZP). When Y2O3 and CeO2 are added as stabilizers, they are expressed as Y-TZP, Ce-TZP, etc.

Application of zirconia ceramics;

Among structural ceramics, zirconia ceramics are widely used in the field of structural ceramics because of its high toughness, high bending strength, high wear resistance, excellent thermal insulation performance and thermal expansion coefficient close to that of steel. It mainly includes: Y-TZP grinding balls, dispersed grinding media, nozzles, ball valve seats, zirconia molds, miniature fan shafts, optical fiber pins, optical fiber sleeves, wire drawing molds and cutting tools, wear-resistant tools, clothing buttons, watch cases and watchbands, bracelets and pendants, ball bearings, light golf clubs and other normal-temperature wear-resistant parts.

In terms of functional ceramics, its excellent high temperature resistance is used as induction heating pipes, refractories and heating elements. Zirconia ceramics have sensitive electrical properties and are mainly used in oxygen sensors, solid oxide fuel cells, SOFC and high temperature heaters. Zirconia has a high refractive index (n-2 1 22). Add some coloring elements (V2O5, MoO3, Fe2O3, etc. ) to ultrafine zirconia powder, which can be made into colorful translucent polycrystalline ZrO2 material, shining like a natural gem, and can be made into various decorations. In addition, zirconia is also widely used in thermal barrier coatings, catalyst carriers, medical care, refractories, textiles and other fields.

Advantages: Compared with metal, zirconia ceramics have high hardness, wear resistance, corrosion resistance and high temperature resistance, and the high temperature performance is incomparable to metal. As for the use, it mainly depends on the demand.

Zirconia ceramics will replace traditional metals and become the new favorite of major industries, which is determined by its high performance. According to the forecast of the national department, the future market scale of zirconia is trillions, with broad prospects. At present, a large number of industries have adopted zirconia as the first material.